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Home My WebLink AboutItem K August 14. 2000 STAFF REPORT • � r1 . To: Mayor and Members of the City Council Attention: Dan Dorsey,Acting City Manager From: Lee Whittenberg,Director of Development Services Subject: CITY RESPONSE LETTER RE: DRAFT SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH, CALIFORNIA RECOMMENDATION Authorize the Mayor to sign the draft response letter, with any additional comments determined appropriate, and instruct staff to forward to the Environmental Quality Control Board a copy of the signed letter. Receive and File Staff Report. DISCUSSION The Environmental Quality Control Board and the City Council has previously received a Staff Report and provided a comment letter to the Navy regarding "Draft Site Evaluation Work Plan, Installation Restoration Program Sites 4, 5, and 6—Weapons Support Facility, California" in April and May, 1998. A copy of the approved comment letter is provided as Attachment 3 to the July 26, 2000 EQCB Staff Report for the information of the City Council. The report now before the City Council is the "Draft Removal Site Evaluation Report", which presents the findings, conclusions, and recommendations of the field investigations conducted in accordance with the"Draft Site Evaluation Work Plan",and will enable the Department of the Navy to support one of the following decisions for soil and/or groundwater at each of the subject sites: o No further action; o Removal action; or AGENDA ITEM C:VNy Documents\NAVWPSTADDraft RSE,IR Sites 4,5,and 6.City Council Report.doc\LW\07-27-00 City Response Letter re:Draft Removal Site Evaluation Report, IR Sites 4, 5, and 6, Naval Weapons Station, Seal Beach City Council Staff Report August 14, 2000 o Further evaluation. The Department of the Navy (DON)has circulated the above referenced document and is requesting comments by August 22, 2000. This meeting is the last regular meeting of the City Council prior to the comment deadline date. Overview of Proposed Project: Staff has prepared a "Draft Comment Letter" for consideration by the EQCB on July 26, 2000, provided as Attachment 1 to the EQCB Staff Report of July 26, 2000. The EQCB considered and acted on this matter on July 26, 2000, and the matter has been forwarded to the City Council for consideration this evening. The draft comment letter is provided as Attachment A. The comment letter incorporates minor revisions recommended by the EQCB, with those revisions being indicated by double-strikethrough for and by bold and italics for language to be added. Due to the extensive nature of the document (over 6,800 pages), staff provided portions of the subject document without the Appendices, A through S, for the information of the EQCB. Staff provided the Executive Summary, Table of Contents, Acronyms/Abbreviations, Section 7 — Findings, Conclusions, and Recommendations, and Section 8, References (See Attachment 2 of EQCB Staff Report, dated July 26, 2000). The complete report, including all Appendices, which comprise the majority of the document, is available for review at the Department of Development Services, City Hall, 211 Eighth Street. Please refer to Attachment B, EQCB Staff Report, dated July 26, 2000 for a summary of the following: o Overview of Draft Removal Site Evaluation (RSE) Report: o Organization of Draft Removal Site Evaluation (RSE) Report: o Description of IR Sites 4, 5, and 6, Overview of Contamination, and Recommended Actions: o Document Availability: o Investigation Response to Previous City Concerns: RECOMMENDATION Authorize the Mayor to sign the draft response letter, with any additional comments determined appropriate, and instruct staff to forward to the Environmental Quality Control Board a copy of the signed letter. Receive and File Staff Report. Draft RSE,IR Sites 4,5,and 6.City Council Report 2 City Response Letter re:Draft Removal Site Evaluation Report, IR Sites 4, 5, and 6, Naval Weapons Station, Seal Beach City Council Staff Report August 14, 2000 NOTED AND APPROVED d , � / � � > Whittenberg,Director Dan D• sey Development Services Departmen Acting City Manager ATTACHMENTS: (2) Attachment A: Draft Comment Letter to Weapons Support Facility, Seal Beach re: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6—Naval Weapons Station, Seal Beach" Attachment B: Environmental Quality Control Board Staff Report re: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 — Naval Weapons Station, Seal Beach", dated July 26, 2000, with Attachments: Attachment 1: Draft Comment Letter to Weapons Support Facility, Seal Beach re: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 — Naval Weapons Station, Seal Beach" Attachment 2: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 — Naval Weapons Station, Seal Beach", prepared for Naval Facilities Engineering Command, Southwest Division, by Bechtel National. Inc., dated June 2000 (Executive Summary, Table of Contents, Acronyms/Abbreviations, Section 7 — Findings, Conclusions, and Recommendations, and Section 8, References, not including remainder of document, Tables and Figures,and Appendices A through S) Attachment 3: City of Seal Beach comment letter to Weapons Support Facility re: "Draft Site Evaluation Work Plan, Installation Restoration Sites 4, 5, and 6 — Weapons Support Facility", letter dated April 27, 1998 Draft RSE,IR Sites 4,5,and 6.City Council Report 3 City Response Letter re:Draft Removal Site Evaluation Report, IR Sites 4, 5, and 6, Naval Weapons Station, Seal Beach City Council Staff Report August 14, 2000 ATTACHMENT A DRAFT COMMENT LETTER TO WEAPONS SUPPORT FACILITY, SEAL BEACH RE: "DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH" Draft RSE,IR Sites 4,5,and 6.City Council Report 4 r s ar.. .44C 'CITY HALL • 211 fIGHT“MEET-. ,;,,"$ ALBEACH,CALIFORNIA 9074046379' (562)431-2527 a August 14,2000 Department of Navy Naval Weapons Station, Seal Beach Attn: Pei-Fen Tamashiro, Installation Restoration Coordinator 800 Seal Beach Boulevard Seal Beach,CA 90740-5000 Dear Ms.Tamashiro: SUBJECT: CITY OF SEAL BEACH COMMENTS RE: DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6-NAVAL WEAPONS STATION, SEAL BEACH The City of Seal Beach has reviewed the above referenced document and is in general agreement with the proposed remediation determinations for Installation Restoration Program Sites 4, 5, and 6. The City previously provided comments on the "Work Plan" for these removal site evaluation investigations in April 1998. The determination of the Navy is that all AOPCs are recommended for "no further action", and those determinations seem to be well supported by the extensive technical evaluations conducted for each AOPC. The overall structure of the document is well organized, with the Executive Summary being particularly helpful to the general reader. The Executive Summary Tables ES-1 through ES- 5 are invaluable in allowing the general reader to: obtain a broad overview of the estimated human-health and ecological risks at each site; and to quickly obtain an overview of the conclusions for each AOPC by medium (soil, sediment, or groundwater), fate and transport, human-health risk assessment, ecological risk assessment, and recommended action at each site. In regards to IR Site 4, the City supports the determinations of"no further action" for each AOPC. However,for AOPC 2A and AOPC 2R, a potential adverse health impact from lead exposure is indicated for a future residential scenario. The City of Seal Beach recognizes that a future residential scenario at these locations, adjacent to Edinger Avenue, is very C:\My Documents\NAVWPSTA\Draft RSE,IR Sites 4,5,and 6.CC Comment L.etter.doc\LW\08-14-00 City of Seal Beach Comment Letter re: 'Draft Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6-Naval Weapons Station, Seal Beach, California- August alifornia"August 14, 2000 speculative. However, the City would request preparation of a file document regarding these two locations of potential lead health impacts if any future residential development is ever contemplated or proposed for these AOPCs. In regards to IR Site 5, the City supports the further evaluation of unexploded ordnance (UXO) at this site, and the removal of any additional UXO located on the site. In addition, our staff has reviewed the UXO Survey Report and Radiation Survey Report, Appendices C and D respectively, and these documents fully address the concerns and reflect the work plan methodologies set forth in the approved "Work Plan" for these investigations. The City has a concern regarding ammonia groundwater levels. On page ES-17, it is indicated that the level of ammonia in groundwater could remain above the screening level for 50 years. The City would request implementation of a groundwater monitoring program to monitor the level of ammonia in order to detect if the level increases over time. In regards to IR Site 6, the City has a concern regarding ammonia groundwater levels. On page ES-23, it is indicated that the level of ammonia in groundwater could remain above the screening level for 50 years. The City would request implementation of a groundwater monitoring program to monitor the level of ammonia in order to detect if the level increases over time. Lastly, the City appreciates the response of the Navy to our concerns regarding the "Work Plan" regarding these IR Sites. Although all of our requests and concerns were not resolved in the manner requested by the City, the Navy clearly set forth why those requests could not be accommodated, and the efforts of clearly communicating those reasons to the City are sincerely appreciated. Thank you for allowing us to comment on the draft "Removal Site Evaluation Report" for IR Sites 4, 5, and 6. If you have any questions or require further information, please contact Mr. Lee Whittenberg, Director of Development Services Department, (562) 431-2527, extension 313, at your earliest convenience. He will be able to respond to any additional questions which you may have regarding this matter. Sincerely, /al° IV 4 41",42"--, Patricia E. Campbell .41,81111.1. ' - III Mayor, City of Seal Beach C ,irm.n, Environmen a •ua Ity Control Board cc: City Council Environmental Quality Control Board Acting City Manager Director of Development Services Draft RS E,IR Sites 4.5,and 6.CC Comment Letter 2 City Response Letter re:Draft Removal Site Evaluation Report, IR Sites 4, 5, and 6, Naval Weapons Station, Seal Beach City Council Staff Report August 14, 2000 ATTACHMENT B ENVIRONMENTAL QUALITY CONTROL BOARD STAFF REPORT RE: "DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 — NAVAL WEAPONS STATION, SEAL BEACH", DATED JULY 26, 2000, WITH ATTACHMENTS: Attachment 1: Draft Comment Letter to Weapons Support Facility, Seal Beach re: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 — Naval Weapons Station, Seal Beach" Attachment 2: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 — Naval Weapons Station, Seal Beach", prepared for Naval Facilities Engineering Command, Southwest Division, by Bechtel National. Inc., dated June 2000 (Executive Summary, Table of Contents, Acronyms/Abbreviations, Section 7 — Findings, Conclusions, and Recommendations, and Section 8, References, not including remainder of document, Tables and Figures, and Appendices A through S) Attachment 3: City of Seal Beach comment letter to Weapons Support Facility re: "Draft Site Evaluation Work Plan, Installation Restoration Sites 4, 5, and 6 — Weapons Support Facility", letter dated April 27, 1998 Draft RSE,IR Sites 4,5,and 6.City Council Report 8 July 26, 2000 STAFF REPORT To: Chairman and Members of the Environmental Quality Control Board From: Lee Whittenberg, Director of Development Services Subject: CITY RESPONSE LETTER RE: DRAFT SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH, CALIFORNIA RECOMMENDATION Authorize the Chairman to sign the draft response letter, with any additional comments determined appropriate. Instruct staff to forward to the City Council for consideration and approval of final Comment Letter. Receive and File Staff Report. DISCUSSION The Environmental Quality Control Board and the City Council has previously received a Staff Report and provided a comment letter to the Navy regarding "Draft Site Evaluation Work Plan, Installation Restoration Program Sites 4, 5, and 6 - Weapons Support Facility, California" in April and May, 1998. A copy of the approved comment letter is provided as Attachment 3 for the information of the Board. The report now before the EQCB is the "Draft Removal Site Evaluation Report", which presents the findings, conclusions, and recommendations and will enable the Department of the Navy to support one of the following decisions for soil and/or groundwater at each of the subject sites: ❑ No further action; ❑ Removal action; or ❑ Further evaluation. The Department of the Navy (DON) has circulated the above referenced document and is requesting comments by August 22, 2000. This meeting is the last regular meeting of the Board prior to the comment deadline date. C:My Documents\NAVWPSTA\Draft RSE,IR Sites 4,5,and 6.EQCB.doc\LW\07-13-00 Draft Removal Site Evol;intion (RSE)Report - IR Sires 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 Overview of Proposed Project: DON is requesting comments on the subject document by August 22, 2000. Staff has prepared a "Draft Comment Letter" for consideration by the EQCB, provided as Attachment 1. Assuming EQCB Consideration and action of this matter on July 26, 2000, the matter will then be forwarded to the City Council for consideration on August 14, 2000. Due to the extensive nature of the document (over 6,800 pages), staff is providing portions of the subject document without the Appendices, A through S, for the information of the EQCB. Staff is providing the Executive Summary, Table of Contents, Acronyms/Abbreviations, Section 7 - Findings, Conclusions, and Recommendations, and Section 8, References (See Attachment 2). The complete report, including all Appendices, which comprise the majority of the document, is available for review at the Department of Development Services, City Hall, 211 Eighth Street. Overview of Draft Removal Site Evaluation (RSE) Report: The objective of the subject report is to supplement data obtained during previous site investigations at Site 4 (Perimeter Road), Site 5 (Clean Fill Disposal Area), and Site 6 (Explosives Burning Ground), and present findings, conclusions, and recommendations. The RSE investigations accomplished the following: o defined the nature and extent of chemicals of potential concern (COPCs) in soil and groundwater; o further refined existing geological and hydrogeological site models; o evaluated the fate and transport of COPCs from soil to groundwater and within groundwater; and o evaluated soil and groundwater to assess the potential threat to human health and the environment through risk assessments. Based on the approved RSE Work Plan, screening criteria were compiled for soil and groundwater. The sampling design for the IR sites included statistical and judgmental soil sample collection and analysis at planned and step-out sampling locations. Field screening was conducted for munitions-related compounds in soil at IR Sites 5 and 6. Soil gas screening was conducted at IR Site 5 for volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs). Based on field screening results, soil samples were sent to a stationary laboratory for confirmation analysis. Soil and groundwater samples from these three sites were analyzed in a stationary laboratory for site-specific chemicals of potential concern (COPCs). Draft RSE,IR Sites 4,S,and 6.EQCB 2 Draft Removal Sue Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 COPCs at IR Site 4 include: metals including hexavalent chromium, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dioxins/furans. COPCs at IR Site 5 include: metals including hexavalent chromium, VOCs, SVOCs, PCBs, and nitroaromatics/nitramines. In addition, UXO is reportedly present at IR Site 5. COPCs at IR Site 6 include: metals including hexavalent chromium, VOCs, SVOCs, PAHs, PCBs, nitroaromatics/nitramines, and ammonia. Estimated human-health risk values for the sites for the scenarios defined in the RSE Work Plan are summarized in Tables ES-1 and ES-2. Conclusions and recommendations for the subject sites are summarized in Tables ES-3 through ES-5, respectively.' Organization of Draft Removal Site Evaluation (RSE) Report: The document consists of the RSE Report, which is organized into 7 sections, and supplemental information that are included as Appendices A through S. The sections of the RSE Report and their contents are summarized below: 0 "Draft Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 - Naval Weapons Station, Seal Beach, California" (Volume I; 309 pages) ❑ Executive Summary ❑ Acronyms/Abbreviations ❑ Section 1, Introduction - provides the purpose, regulatory status, operable unit designation, report preparation and report organization. ❑ Section 2, Site Background - describes the background of the project in terms of the facility location and history as it relates to the subject sites, and a summary of previous investigations. o Section 3, Physical Characteristics of the Study Area - presents the environmental setting of the project in the context of both the regional and local geology and hydrogeology, as well as the hydrology, ecology, surrounding population, and climate. O Section 4, Investigation and Evaluation Methods - addresses the RSE objectives for each site and discusses the data quality objectives process, the field data collection and sampling activities, work plan modifications, and data reduction and evaluation methods. o Section 5, Investigation Results - provides the results of the geochemical evaluation of metals in soil, and for each of the sites discusses field investigation activities, geological and hydrogeological findings, the nature and extent of contamination, 1 "Draft Removal Site Evaluation (RSE) Report - Installation Restoration Sites 4, 5, and 6, Naval Weapons Station, Seal Beach, California", prepared for Southwest Division, Naval Facilities Engineering Command by Bechtel National, Inc., dated June 2000, pages ES-1 and ES-2. Draft RSE,IR Sites 4,S,and 6.EQCB 3 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 contaminant fate and transport, and presents a refined conceptual model and summary of the nature and extent of contamination. O Section 6, Human and Ecological Risk Assessment - presents the human-health risk assessment, including discussion on chemicals of potential concern, exposure assessment, exposure assumptions, toxicity assessment, risk characterization, results, and uncertainty analysis. The ecological screening risk assessment includes problem formulation, exposure assessment, biological effects assessment, characterization of ecological hazards, and uncertainty analysis. o Section 7, Findings, Conclusions and Recommendations - presents a summary of findings for each site, including soil and groundwater as appropriate, and area of potential concern within each site, and conclusions and recommendations. ❑ Section 8, References -lists the reference documents utilized in the preparation of this report. 0 "Draft Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 - Naval Weapons Station, Seal Beach, California", Tables and Figures (Volume II; 361 pages) The appendices to the RSE Work Plan include: o A Field Investigation Methods and Procedures (Volume III; 39 pages) ❑ B Geophysical Survey Report (Volume III; 32 pages) ❑ C UXO Survey Report (Volume III; 44 pages) ❑ D Radiation Survey Report (Volume III; 26 pages) ❑ E Health and Safety Close-out Report (Volume III; 14 pages) ❑ F Trench Logs, Geologic Borehole Logs, and Well Construction Details (Volume III; 292 pages) ❑ G Cone Penetrometer Test Data (Volume III; 25 pages) o H Geotechnical Laboratory Results (Volume III; 52 pages) ❑ I Tidal Influence Survey (Volume III; 15 pages) o J Laboratory Analytical Data (Volume IV; 1,118 pages) ❑ K Field Measurements (Volume V; 3 pages) o L Calculation of Total 2,3,7,8-TCDD-Equivalent Concentration (Volume V; 53 pages) ❑ M Geochemical Assessment for Select Metals in Soil (Volume V; 64 pages) ❑ N Surveyor's Report (Volume V; 472 pages) ❑ 0 Data Validation Reports (Volume VI; 1,185 pages), (Volume VII; 1,152 pages) ❑ P Transport Modeling (Volume VIII; 70 pages) ❑ Q Human-Health Streamlined Risk Assessment, Parts 1 through 4 (Volume VIII; 530 pages), Parts 5 through 7 (Volume IX; 879 pages) Draft RSE,IR Sites 4,5,and 6.EQCB 4 Draft Removal Site Evaluation (RSE) Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ❑ R Screening Ecological Risk Assessment (Volume IX; 174 pages) ❑ S Aerial Photograph Review (Volume IX; 33 pages)2 Description of IR Sites 4, 5, and 6, Overview of Contamination, and Recommended Actions: Site 4: Perimeter Road - consists of the road that extends around the Weapons Support Facility for a length of approximately 12 miles. From the mid-1960s to 1973, about one to three times per year, the perimeter road was sprayed with unknown quantities of waste oil for dust control. Weeds on the unpaved roads and nearby fields were cropped and disked for fire control, and oil was then sprayed over the area and disked into the soils for dust control. The waste oil used was generated by the facility and included Bunker C fuel oil. From 1972 through 1973, an estimated 40,000 gallons of waste oil, generated by off-facility crude oil operations, petroleum refineries, and from oil spills, were sprayed by a contractor in two or three applications on the roadway. Off-site contracting of waste oil spraying was discontinued when lead content in oils of 40 parts per million and trace amounts of other metals were found. Since early 1974, the perimeter roads have been sprayed with a quality-controlled penetrating oil consisting of 70 percent water and 30 percent emulsified agent. Overview of Contamination: Below is a summary of the various problems investigated at IR Site 4: ❑ Perimeter road of station was sprayed with waste oil for dust control. ❑ Initial Site Inspection soil sampling indicated the presence of metals, semivolatile organic compounds (SVOCs), pesticides, dioxins, and furans. ❑ Additional soil sampling by AccuTek Inc., in 1995 indicated presence of total recoverable petroleum hydrocarbons (TRPH), lead, SVOC, dioxins, and furans in soil. ❑ Remedial Investigation (RI) soil sampling indicated the presence of elevated lead concentrations adjacent to the perimeter road (Site 7 lead "hot spot"). ❑ Based on the previous analytical results, 12 areas of potential concern (AOPC) were identified for evaluation. ❑ Heavy metals, polynuclear aromatic hydrocarbons (PAH), and polychlorinated biphenyls (PCBs) in soil are not identified. o Lateral and vertical extent of COPCs is not defined. Recommended Actions: O All areas of potential concern (AOPCs) are recommended for "no further action", based on the findings and conclusions for soil and groundwater at each site.' 2 Op.Cit, Table of Contents, pages xxi and xxii. Draft RSE,IR Sites 4,S,and 6.EQCB 5 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 Site 5: Clean Fill Disposal Area - is a 4.1-acre area located in the southwest quadrant of the facility, near the southeast corner of Kitts Highway and Bolsa Avenue. Approximately 3.3 acres of this site are covered with disposal fill materials. IR Site 5 is located within the boundaries of the National Wildlife Refuge. In 1944, during initial construction of the facility, construction debris and clean fill were disposed of in an area approximately 400 feet northwest of Building 235. During an Initial Assessment Study (IAS) site visit, the site was observed to be approximately 3 feet above the adjacent salt marsh and was covered with vegetation. Unexploded ordnance (UXO) was reportedly found at this site, and trucks had been observed in the past off-loading ordnance related materials such as shell casings mixed with construction debris. Overview of Contamination: Below is a summary of the various problems investigated at IR Site 5: ❑ Soil sampling conducted mostly around perimeter of site; entire site not sampled due to reported presence of unexploded ordnance (UXO). ❑ Site Inspection (SI) sampling indicated the presence of low concentrations in soil of VOCs, SVOCs, and pesticides; no PCBs. ❑ SI sampling indicated the presence of metals concentrations in soil in excess of Stationwide Background concentrations for chromium, copper, lead, mercury, nickel, and zinc, with lead greater than U.S. EPA Region IX Preliminary Remediation Goal (PRG). Antimony, arsenic, barium, and thallium concentrations in excess of maximum concentration limits (MCLS) reportedly detected in groundwater. ❑ Focused Site Inspection (FSI) soil sampling indicated the presence of mercury concentrations below Stationwide Background, and lead concentrations in excess of Stationwide Background in 4 samples. ❑ Chemicals of potential concern (COPCs) for soil not identified due to limited sampling conducted around the perimeter of the site. ❑ Lateral and vertical extent of COPCs are not defined. ❑ Potential sources of metals detected in groundwater have not been identified in soil. ❑ Extent of potential UXO is not defined. ❑ Potential presence of radioactive material not known. Recommended Actions: ❑ All areas of potential concern (AOPCs) are recommended for "no further action", based on the findings and conclusions for soil and groundwater at each site.` aOp. Cit., pages ES-4 through ES-14 Op. Cit., pages ES-16 through ES-17 Draft RSE,IR Sites 4,5,and 6.EQCB 6 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ❑ Based on the results of the UXO survey, it is recommended that the potential for UXO presence at the site be further evaluated and any UXO identified by this evaluation be removed from the site.' Site 6: Explosives Burning Ground - is located approximately 500 feet northwest of the Station Landfill (IR Site 7), near the south-central portion of the facility. Site 6 is also located within the boundaries of the National Wildlife Refuge. This investigation report indicates the site is triangular in shape and covers an area of approximately 16.8 acres. From 1944 to 1971, this area was used for open burning of waste ordinance and materials used during fire training exercises. Damaged or leaking munitions or ordnance handled by most ordnance operations at the station were reportedly taken by railcar to the burning ground for disposal. The enactment of air quality regulations, along with complaints from citizens living in the area, resulted in a self-imposed ban on open burning in 1970. From 1945 to the early 1950s, waste Explosive-D, Explosive-D sludge, waste black powder, fog oil, and miscellaneous pyrotechnics were sent to the burning ground. From 1945 to 1970, waste smokeless powder was transported to the burning ground for disposal. Most of the wastes were contained in five-gallon powder cans and transported to a point approximately 800 feet southwest of the Marshalling Yard. Ordnance wastes would then be trucked to the edge of a "20-foot" trench with unknown depth. Wastes would then be placed in the trench in the following order: ❑ Fog oil (a petroleum derivative), including the metal smoke pot; ❑ Damaged or excess pyrotechnics, including metal parts, or other ordnance contaminated material, and; ❑ Explosive-D, black powder, and smokeless powder emptied from five-gallon powder cans. The trench would then be ignited by a trail of ordnance powder. The duration of the burn was reportedly less than five minutes. When the trench became full with metal debris, it was covered with soil and a new trench was dug for future burns. The total number of trenches used for open burning is unknown. In the late 1960s, a 50-pound explosive waste limitation was implemented. Ordnance wastes were then placed into unlined shallow pads, instead of trenches, and burned. Between 1969 and 1970, the station imposed a ban on open burning, where open burning would be allowed only for emergency disposal. From 1968 through 1972, approximately 120 55-gallon drums of waste Otto Fuel and contaminated Agitene and solids were disposed of at Site 6; the method of burning is 5 Op. Cit., page ES-16 Draft RSE,IR Sites 4,5,and 6.EQCB 7 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 unknown. From 1969 to 1971, damaged smoke signals, pyralin patches, pyralin wads, and illuminating signals were burned at Site 6. In December 1970, underwater demolition charges were burned at Site 6. In June 1971, a truckload of Air Force fire (Napalm) bombs were burned at the site. Overview of Contamination: Below is a summary of the various problems investigated at IR Site 6: ❑ Burning of ordnance with the addition of fog oil in trenches at the site. The trenches reportedly contain metal debris. ❑ Initial SI sampling indicated the presence of ammonia, PAH, and TPH in soil; no explosives were reportedly detected. Only ammonia was detected in groundwater. ❑ Operable Unit (OU) 4 SI sampling indicated presence of low concentrations of TPH in soil and groundwater. Benzo(a)pyrene reported above PRG in one soil sample. Elevated levels of nitrite/nitrate N in groundwater. ❑ COPCs for soil not well defined due to complex chemical nature of ordnance burned. ❑ Extent of COPCs in soil not defined. ❑ Location of trenches not known; trench locations inferred from aerial photo review. Recommended Actions: ❑ All areas of potential concern (AOPCs) are recommended for "no further action", based on the findings and conclusions for soil and groundwater at each site.6 Document Availability: The subject document is available for review at the Mary Wilson Library, 707 Electric Avenue, and at the Department of Development Services, Seal Beach City Hall, 211 Eighth Street. Investigation Response to Previous City Concerns: AS indicated previously, the City has commented on the "Work Plan" for these investigations in 1998 (Please refer to Attachment 3). In November 1998, the "Final Work Plan" and responses to our comments was received and provided to the City Council and EQCB. Staff has reviewed the concerns of the City at that time, the responses from the Navy, and attempted to thoroughly review the current document to ensure that those concerns have been adequately addressed in the 6 Op. Cit., pages ES-19 through ES-23 Draft RSE,ER Sites 4,5,and 6.EQCB 8 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report Jut) 26, 2000 investigations conducted regarding these sites. At the time of review of the "Work Plan", the following major concerns were expressed by the City: (1) IR Site 5, page 4-45, indicates human-health risk assessments will be based on two exposure scenarios: tour guide and habitat restoration/maintenance supervisor. The City is concerned that a residential exposure scenario is not proposed for this location. Although it may seem a remote possibility that this site would ever become available for a use other than that a discussed within the draft RSE Work Plan, this possibility should not be precluded. if it unreasonable to undertake that level of analysis at this time, due to the speculative nature of the future use of the site, that determination should be clearly stated within the document. In addition, any future documents relating to this site should clearly and explicitly discuss this determination, and indicate if the site is eventually released for a non-natural resource protection use, the Navy will restore the site to the appropriate residential standards. Navy Response: After discussions with the U.S. Fish and Wildlife Service, it was determined the two proposed scenarios for evaluation were appropriate. The human-health risk analysis evaluates potential impacts upon tour guides and habitat restoration/maintenance supervisors. The subject area is part of the upland ecosystem for the National Wildlife Refuge. (2) IR Site 5, page 4-53, indicates "Because of the potential for the Site 5 fill to be transported to the salt water marsh, sediment along the edge of Site 5 may be sampled." (Emphasis added). The City strongly requests this language be changed to "shall be sampled". In addition, the City requests that the Navy consider sampling along the edge of Site 5, adjacent to the National Wildlife Refuge shoreline at each of the proposed sampling grids which contain a shoreline area, as indicated on Figure 4-12, page 4-47. This would result in the taking of an additional 11 sediment samples. Navy Response: Sediment along the edge of Site 5 will be sampled as part of the delineation of the extent of COPCs in soil; however, sediment sample collection depends on detecting COPC concentrations in soil exceeding the screening criteria. (3) IR Site 6, page 4-59 at the bottom of the page, indicates "Risk estimates will be based on COPCs identified in soil at the site and two exposure scenarios: tour guide and habitat restoration/maintenance supervisor." However, page 4-57, Screening Criteria, indicates "Screening criteria used for delineation of the extent of organic compounds in soil will be residential PRGs or an apparent trend." Draft RSE,IR Sites 4,S,and 6.EQCB 9 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 The City is confused in the apparent discrepancy between these two statements, and would request that residential PRGs be used throughout the analysis at IR Site 6, for the same reasons discussed above regarding 1R Site 5. Navy Response: The language was revised to state: "the extent of organic COPCs will be delineated to non-detect or until a concentration trend has been established." (4) IR Site 6, page 4-66, "Metals, VOCs, SVOCs, and PCBs in Soil", first sentence, first line, references IR Site 5. Please correct. Navy Response: The reference to Site 5 is correct, and additional clarifying language was provided. (5) IR Site 6, Appendix Al, "Draft Field Sampling Plan", page A1-24, indicates that an archaeological survey was conducted by Archaeological Resource Management Corporation (ARMC) in 1980, and the survey reports do not indicate the presence of an archaeological site at IR Site 6. City staff has reviewed the referenced report and is concerned that the ARMC report indicates: "In sum, most of the area of the property could not be walked over in the standard procedure of equally spaced, parallel transects. The procedure used instead, simply stated, was to walk over all areas that it was possible to walk over. At the time of the survey this consisted of portions of the east half and the south end of the property (see figure). While there was very little standing water in these areas during the survey, most of the area was to soft to walk across. The west half of the property was underwater." Given the uncertainty as to which portions of the survey area of 160 acres were actually observed as part of the walkover survey, and additional discussion within the ARMC report regarding the observance of shell deposits, although located among areas of considerable man-caused disturbance, the City is concerned that additional precautions should be taken regarding potential cultural resources at IR Site 6. The City requests implementation of a discovery procedure and worker instructional presentation regarding potential cultural resources at IR Site 6, similar to those programs established for the Background Study Sampling Areas. Those requested procedures and presentations are set forth in "Archaeological Resource Protection Plan for the Background Study Sampling Area at Naval Weapons Station, Seal Beach, Orange County, California ", prepared by Chambers Group, Inc, and dated August 1995. Draft RSE,IR Sites 4,5,and 6.EQCB 10 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 Navy Response: Navy concurred with and implemented this request. In reviewing the subject documents, staff has several points to request clarification on, and those issues are discussed in the draft comment letter. Please refer to Attachment 1 to review the draft comment letter. RECOMMENDATION: Authorize the Chairman to sign the draft response letter, with any additional comments determined appropriate. Instruct staff to forward to the City Council for consideration and approval of final Comment Letter. Receive and File Staff Report. ( Whittenberg, irector Department of Development Services ATTACHMENTS: (3) Attachment 1: Draft Comment Letter to Weapons Support Facility, Seal Beach re: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 -Naval Weapons Station, Seal Beach" Attachment 2: "Draft Removal Site Evaluation Report, Installation Restoration Program Sites 4, 5, and 6 - Naval Weapons Station, Seal Beach", prepared for Naval Facilities Engineering Command, Southwest Division, by Bechtel National. Inc., dated June 2000 (Executive Summary, Table of Contents, Acronyms/Abbreviations, Section 7 - Findings, Conclusions, and Recommendations, and Section 8, References, not including remainder of document, Tables and Figures, and Appendices A through S) Attachment 3: City of Seal Beach comment letter to Weapons Support Facility re: "Draft Site Evaluation Work Plan, Installation Restoration Sites 4, 5, and 6 - Weapons Support Facility", letter dated April 27, 1998 Draft RSE,IR Sites 4,5,and 6.EQCB 11 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ATTACHMENT 1 DRAFT COMMENT LETTER TO WEAPONS SUPPORT FACILITY, SEAL BEACH RE: "DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH" Draft RSE,IR Sites 4,S,and 6.EQCB 12 Draft Removal Site Evaluation (RSE)Report - IR Sires 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 August 14, 2000 Department of Navy Naval Weapons Station, Seal Beach Atm: Pei-Fen Tamashiro, Installation Restoration Coordinator 800 Seal Beach Boulevard Seal Beach, CA 90740-5000 Dear Ms. Tamashiro: R O SUBJECT: CITY OF SEAL BEACH COMMENTS RE: DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH The City of Seal Beach has reviewed the above referenced document and is in general agreement with the proposed remediation determinations for Installation Restoration Program Sites 4, 5, and 6. The City previously provided comments on the "Work Plan" for these removal site evaluation investigations in April 1998. The determination of the Navy is that all AOPCs are recommended for "no further action", and those determinations seem to be well supported by the extensive technical evaluations conducted for each AOPC. The overall structure of the document is well organized, with the Executive Summary being particularly helpful to the general reader. The Executive Summary Tables ES-1 through ES-5 are invaluable in allowing the general reader to: obtain a broad overview of the estimated human- health and ecological risks at each site; and to quickly obtain an overview of the conclusions for Draft RSE,IR Sites 4,S,and 6.EQCB 13 Draft Removal Site Evo/'irnion (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 each AOPC by medium (soil, sediment, or groundwater), fate and transport, human-health risk assessment, ecological risk assessment, and recommended action at each site. In regards to IR Site 4, the City supports the determinations of "no further action" for each AOPC. However, for AOPC 2A and AOPC 2R, a potential adverse health impact from lead exposure is indicated for a future residential scenario. The City of Seal Beach recognizes that a future residential scenario at these locations, adjacent to Edinger Avenue, is very speculative. However, the City would request preparation of a file document regarding these two locations of potential lead health impacts if any future residential development is ever contemplated or proposed for these AOPCs. 0130:1 In regards to IR Site 5, the City supports the on of unexploded ordnance (UXO) at this site, and the removal of any additional UXO located on the site. In addition, our staff has reviewed the UXO Survey Report and Radiation Survey Report, Appendices C and D respectively, and these documents fully address the concerns and reflect the work plan methodologies set forth in the approval "Work Plan" for these investigations. The City has a concern regarding ammonia groundwater levels. On page ES-17, it is indicated that the level of ammonia in groundwater could remain above the screening level for 50 years. The City would request implementation of a groundwater monitoring program to monitor of level of ammonia to ensure the level does not significantly increase over time. In regards to IR Site 6, the City has a concern regarding ammonia groundwater levels. On page ES-23, it is indicated that the level of ammonia in groundwater could remain above the screening level for 50 years. The City would request implementation of a groundwater monitoring program to monitor of level of ammonia to ensure the level does not significantly increase over time. Lastly, the City appreciates the response of the Navy to our concerns regarding the "Work Plan" regarding these IR Sites. Although all of our requests and concerns were not resolved in the manner requested by the City, the Navy clearly set forth why those requests could not be accommodated, and that effort of clearly communicating those reasons to the City are sincerely appreciated. Thank you for allowing us to comment on the draft "Removal Site Evaluation Report" for IR Sites 4, 5, and 6. If you have any questions or require further information, please contact Mr. Lee Whittenberg, Director of Development Services Department, (562) 431-2527, extension 313, at your earliest convenience. He will be able to respond to any additional questions which you may have regarding this matter. Draft RSE,IR Sites 4,5,and 6.EQCB 14 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 Sincerely, R III Pattivi Campbell Joseph E. Porter, Mayor, City of Seal Beach Chairman, Environmental Quality Control Board cc: City Council Environmental Quality Control Board Acting City Manager Director of Development Services Draft RSE,IR Sites 4,5,and 6.EQCB 15 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ATTACHMENT 2 "DRAFT REMOVAL SITE EVALUATION REPORT, INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 - NAVAL WEAPONS STATION, SEAL BEACH", PREPARED FOR NAVAL FACILITIES ENGINEERING COMMAND, SOUTHWEST DIVISION, BY BECHTEL NATIONAL. INC., DATED JUNE 2000 (EXECUTIVE SUMMARY, TABLE OF CONTENTS, ACRONYMS/ABBREVIATIONS, SECTION 7 - FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS, AND SECTION 8, REFERENCES, NOT INCLUDING REMAINDER OF DOCUMENT, TABLES AND FIGURES, AND APPENDICES A THROUGH S) Complete Report, including Appendices A through S, available at Department of Development Services for review Draft RSE,IR Sites 4,5,and 6.EQCB 16 Southwest Division Naval Facilities Engineering Command Contracts Department 1220 Pacific Highway San Diego, California 92132-5190 Contract No. N68711-92-D-4670 COMPREHENSIVE LONG-TERM ENVIRONMENTAL ACTION NAVY CLEAN II DRAFT REMOVAL SITE EVALUATION REPORT INSTALLATION RESTORATION PROGRAM SITES 4, 5, AND 6 NAVAL WEAPONS STATION, SEAL BEACH SEAL BEACH, CALIFORNIA Volume I of IX CTO-0151/0197 June 2000 Prepared by: BECHTEL NATIONAL, INC. 1230 Columbia Street, Suite 400 San Diego, California 92101-8502 • Signature: � Date:/ ,C1Z Vet) teven W. Draper, CEG No. 1601, RG No. 5119 Signature: _ t l Date: 4/07O Robe A. ape, --. -r CLEAN II C70-0151/0197 Date: 06/22/00 EXECUTIVE SUMMARY This Removal Site Evaluation (RSE) Report has been prepared by Bechtel National, Inc. (BNI), under the Comprehensive Long-Term Environmental Action Navy (CLEAN) 1I contract. The report presents the findings, conclusions, and recommendations of the RSE investigations performed at Department of the Navy Installation Restoration Program (IRP) Sites 4, 5, and 6 at Naval Weapons Station (WPNSTA), Seal Beach, California (Figure ES-1). The objective of the RSE investigations was to supplement data obtained during previous site investigations at the Perimeter Road (IRP Site 4), the Clean Fill Disposal Area (IRP Site 5), and the Explosives Burning Ground (IRP Site 6). The RSE investigations for IRP Sites 4, 5, and 6 accomplished the following: • defined the nature and extent of chemicals of potential concern (COPCs) in soil and groundwater, • further refined existing geological and hydrogeological site models, • evaluated the fate and transport of COPCs from soil to groundwater and within groundwater, and • evaluated soil and groundwater to assess the potential threat to human health and the environment through risk assessments. The information in this RSE Report will enable the Department of the Navy to support one of the following decisions for soil andIor groundwater at each of IRP Sites 4, 5, and 6: 1) no further action; 2) removal action; or 3) further evaluation. The RSE was conducted in accordance with the RSE Work Plan (BNI 1998), which was approved by the regulatory agencies. The RSE objectives for IRP Sites 4, 5, and 6 have been satisfied as a result of the various investigations and assessments conducted. The RSE was performed for each of the areas of potential concern (AOPCs) at the sites. The sites/AOPCs and corresponding soil and groundwater sampling locations are shown on Figures ES-2 through ES-6. Based on the RSE Work Plan (BNI 1998), screening criteria were compiled for soil and groundwater. These criteria included stationwide and statewide statistical background values, preliminary remediation goals (PRGs), and groundwater-quality criteria. Soil and groundwater chemical data from each sample collected at IRP Sites 4, 5, and 6 were then compared to these screening criteria. Analytical results exceeding the screening criteria are presented in discussions of the nature and extent of COPCs and presented on figures. This approach was taken to highlight the relative significance of chemical concentrations and the areas of elevated concentrations at each site/AOPC and each medium. The use of PRG values, for example, as a comparison tool, is for illustration purposes on figures only, not as an indication of the risk posed by these chemical compounds. The overall risk at a given site/AOPC is assessed and discussed separately. Conclusions and recommendations made for IRP Sites 4, 5, and 6 soil and groundwater consist of risk-based decisions, in accordance with the RSE Work Plan (BNI 1998). The human-health risk assessment (HHRA) consisted of a streamlined risk evaluation for baseline risk assessments Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-1 6/192000 8 18 AM tmltsaos0010wornaikvtavylbtcto151vse cr8h1presectonuexl*mtcsufT*o_ooc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) associated with RSE. The decision rule for the risk decision is based on the exposure setting that produces the highest level of estimated risk for the site/AOPC. Estimated human-health risk values for the sites/AOPCs for the scenarios defined in the RSE Work Plan (BNI 1998) are summarized in Tables ES-1 and ES-2. The screening ecological risk assessment (ERA) involved comparing the exposure estimates calculated using measured COPC concentrations in soil and groundwater to toxicological benchmarks. Site descriptions and histories for IRP Sites 4, 5, and 6 are presented in the following sections. RSE investigation results, conclusions, and recommendations by AOPC and medium for IRP Sites 4, 5, and 6 are also presented in the following sections. A summary of findings for soil and groundwater used in formulating conclusions and developing recommendations are discussed for each site/AOPC. Conclusions and recommendations for IRP Sites 4, 5, and 6 are summarized by AOPC/medium in Tables ES-3 through ES-5, respectively. IRP SITE 4 - PERIMETER ROAD • IRP Site 4 consists of the road that extends around WPNSTA, Seal Beach for a length of approximately 12 miles. The southwesternmost portion of the road segment along Edinger Avenue is located adjacent to the National Wildlife Refuge (NWR) (Figure ES-1). From the mid-1960s to 1973, about one to three times per year, the perimeter roads of the facility were sprayed with unknown quantities of waste oil for dust control. From 1972 through 1973, the waste oils were sprayed by a contractor and were generated by off- - facility crude oil operations, petroleum refineries, and oil spills. Off-site contracting of waste oil spraying was discontinued when elevated lead content and trace amounts of other metals were found in the oils (Kearney 1989). Since early 1974, the perimeter roads have been sprayed with quality-controlled penetrating oil consisting of 70 percent water and 30 percent emulsified agent (NEESA 1985). As part of the RSE investigations, soil samples were collected and analyzed to characterize and delineate the lateral and vertical extent of COPCs and characterize the physical and geological properties of AOPCs 1A and 2A (accumulation areas) and 1R through IOR (road). Eight planned soil borings were hand-augered at each AOPC; soil samples were generally collected at depths of 0 to 1 foot below ground surface (bgs) and 2.0 to 2.5 feet bgs. Step-out soil samples were also collected, as necessary, to define the lateral and vertical extent of COPCs. Soil sampling locations are shown on Figure ES-2 through ES-4. Soil samples were analyzed for target analyte list (TAL) metals, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/PCDFs). Three groundwater samples were collected from each of AOPCs 1A and 2A and analyzed for the COPCs. Groundwater sampling locations are shown on Figure ES-4. In general, soils at IRP Site 4 consist of varying amounts of road fill overlying native sediments (Recent deposits). page ES-2 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6119,2000E 16 M.4 tm 1u1tlOt0010u1orwikuu rylb,CtotStvse tlr/n1prese bonu/xtvex* ur tl OOC CLEAN II CTO-0151/0197 Date. 06/22/00 EXECUTIVE SUMMARY (continued) AOPC 1A— SOIL AND GROUNDWATER Two PAHs, benzo(a)pyrene and benzo(b)fluoranthene, were reported at elevated concentrations in soil. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-equivalent concentrations were reported above the residential PRG value in 14 of the 44 soil samples collected at this AOPC. PCBs (Aroclor 1254 and/or Aroclor 1260) were reported at elevated concentrations at four sampling locations. Thirteen metals were reported in soils above the statistical background (including antimony, barium, chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, silver, vanadium, and zinc), and eight metals (antimony, barium, chromium, cobalt, manganese, nickel, silver, and zinc) were reported above the geochemical background determined as part of this RSE. Most of the elevated concentrations of COPCs were found at sampling locations adjacent to the road at 0 to 1 foot bgs. Groundwater samples collected from AOPC lA had reported total dissolved solids (TDS) concentrations similar to that of seawater. PAHs and PCBs were not reported above detection limits in groundwater samples collected from AOPC 1A. The only PCDD/PCDF reported above detection limits was 1,2,3,4,6,7,8,9-octachlorodibenzo-p- dioxin. Six metals (antimony, barium, cadmium, manganese, selenium, and vanadium) and hexavalent chromium were reported at concentrations above detection limits. Antimony and hexavalent chromium were the only metals reported at concentrations above statistical background. None of the antimony concentrations were in excess of the California Ocean Plan (COP) water quality objectives (WQO) (SWRCB 1997). Hexavalent chromium was reported at a concentration exceeding the COP WQO 6-month median concentration but below the United State Environmental Protection Agency (U.S. EPA) ambient water quality criteria (AWQC) for saltwater concentration (as summarized in RWQCB, Central Valley Region 1998). A fate and transport evaluation was conducted to ascertain whether COPCs in soil at IRP Site 4 AOPC 1 A represent a potential future threat to groundwater. Results indicate that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of a fate and transport evaluation conducted for groundwater COPCs indicate that hexavalent chromium might continue to affect groundwater above the groundwater screening criteria at the AOPC. However, the simulation indicates that groundwater at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC, is not affected. AOPC 1 A is a salt marsh habitat within the NWR; therefore, the potential risk to human health is not a concern and was not evaluated. Results of the ERA indicate that several soil COPCs showed hazard quotient (HQ) values greater than 1. However, after comparing these values to background conditions and to the range of toxicity reference values (TRVs), they did not appear ecologically significant. Results of the ERA also indicate that the potential effects of groundwater chemicals of potential ecological concern (COPECs) on general marine life are low, based on Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-3 6/19.'2000 8 18 AM Im wbos0010‘nonvalkylavyttncto1511rse tlrinvesecoonueKlleuecsum•a tloc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) comparing measured groundwater COPEC concentrations to water-quality criteria. Two compounds exceed the water-quality criteria: antimony (HQ of 7.0) and hexavalent chromium (HQ of 4.8). However, it is unlikely that marine life would be adversely affected at these levels. Based on the findings and conclusions for soil and groundwater at AOPC 1A, soil and groundwater are recommended for no further action. AOPC 2A— SOIL AND GROUNDWATER One PAH, benzo(a)pyrene, was reported at an elevated concentration in soil. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 16 of the 34 samples. PCBs (Aroclor 1254 and/or Aroclor 1260) were reported at elevated concentrations at four sampling locations. Metals reported at concentrations above statistical background consisted of antimony, arsenic, barium, chromium, copper, lead, mercury, and zinc. Of these metals, antimony, arsenic, barium, copper, and zinc were not reported at concentrations above the geochemical background. Arsenic (one sample) and lead (12 samples) were reported at elevated concentrations. Most of the elevated concentrations of COPCs were found at sampling locations adjacent to the road at 0 to 1 foot bgs. Groundwater collected from AOPC 2A has reported TDS concentrations similar to seawater. PAHs and PCBs were not reported above detection limits in the groundwater samples collected from AOPC 2A. PCDDs/PCDFs were reported at concentrations above detection limits in all three groundwater samples. Eight metals (antimony, arsenic, barium, cadmium, manganese, selenium, vanadium, and zinc) and hexavalent chromium were reported at concentrations above detection limits. Antimony (three results out of three), arsenic (one result out of three), and hexavalent chromium (one result out of three) were the only metals reported at concentrations above statistical background. None of the antimony concentrations were in excess of COP WQO. Arsenic was reported at a concentration exceeding the COP WQO 6-month median concentration but equal to the U.S. EPA AWQC for saltwater concentration. Hexavalent chromium was reported at a concentration exceeding the COP WQO 6-month median concentration but below the U.S. EPA AWQC for saltwater concentration. A fate and transport evaluation conducted for soil COPCs indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of a fate and transport evaluation conducted for groundwater COPCs indicated that total 2,3,7,8-TCDD-equivalent could continue to affect groundwater at the AOPC above the groundwater screening criteria for 50 years. However, the simulation indicates that groundwater at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC, is not affected. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 3.7 x 10-5, which is within the National Oil and Hazardous Substances Pollution Contingency Plan's (NCP's) generally acceptable risk page ES-4 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/19/2000 8 18 AM U, 1lstlos0010vwrwatkWvyiolcto151 Yse presedronusavececsu'C OOC CLEAN II CTO-015110197 Date 06'22/00 • EXECUTIVE SUMMARY (continued) range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs/PCDFs. The incidental soil ingestion pathway was the main contributor to residential risk. The hazard index (HI) associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The estimated concentrations of lead in the blood of the resident child (15.8 to 35.7 micrograms per deciliter [µg/dL] at 50th to 99th percentiles, respectively) and the adult (10 to 13.1 µgidL at 95th to 99th percentiles, respectively) exceed the lead concentration of concern of 10 µg/dL, indicating the potential adverse health effects from exposure to lead at AOPC 2A. However, the residential scenario assumed for the AOPC is highly improbable. AOPC 2A is a combination of salt marsh habitat and grassland habitat. The ERA indicates that for lead the low-HQ value exceeded 1 for the robin (HQ of 230). However, the high-HQ value did not exceed 1 for robin exposure to lead, indicating that the lead concentrations may not be ecologically significant. The ERA also indicates that the total 2,3,7,8-TCDD-equivalent showed HQ values only slightly exceeding unity for several different indicator species; therefore, total 2,3,7,8-TCDD-equivalent is considered to be of minor ecological significance. Results of the ERA indicate that the potential effects to general marine life are low, based on comparing measured groundwater COPEC concentrations to water-quality criteria. Three compounds slightly exceeded the water-quality criteria: antimony (HQ of 5.3), arsenic (HQ of 4.5), and hexavalent chromium (HQ of 1.2). However, it is unlikely that marine life would be adversely affected at these levels. Based on the findings and conclusions for soil and groundwater at AOPC 2A, soil and groundwater are recommended for no further action. The total cancer risk for soil is within the NCP's generally acceptable risk range of 10-6 to 10-4 under the residential scenario; the HI is less than 1; and blood lead concentrations exceed 10 µg/dL, but are based on the highly improbable residential scenario assumption. The ERA has quantified the soil as having HQ values slightly greater than 1 for several indicator species for PCDDs/PCDFs, but their ecological significance is minor. The ERA indicates a low potential for COPECs to affect marine life. Therefore, AOPC 2A soil and groundwater are recommended for no further action. AOPC 1R — SOIL One PAH, dibenz(a,h)anthracene, was reported at an elevated concentration in soil. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-5 6/19,2000 B 18 AM tm t\soos0010vwrwaikvavyloncto151vse Orsnky.esecuonmex1.xecsum-0 aoc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) in 7 of the 21 samples. Three PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.1 milligrams per kilogram (mg/kg). Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, copper, lead, mercury, selenium, vanadium, zinc, and hexavalent chromium. Of these metals, antimony, chromium, copper, vanadium, and zinc were not reported at concentrations above the geochemical background. Elevated lead concentrations were reported in six samples at 0 to 1 foot bgs and one sample at 2 to 2.5 feet bgs. A fate and transport evaluation conducted for soil COPCs indicated that anthracene and fluorene could affect groundwater at the AOPC above the groundwater screening criteria and that fluorene could affect groundwater at a hypothetical point of discharge into the marine environment, located 30 feet from the AOPC. However, the low ratio of predicted fluorene concentrations to groundwater screening criteria suggests a low potential threat to groundwater. As part of the HHRA, risk to the United States Fish and Wildlife Service (U.S. FWS) staff member, who represents the group participating in the clapper rail predator study, the clapper rail recovery study, and the raptor monitoring study, was calculated. The U.S. FWS staff member was assumed to be exposed to soil at AOPC 1R, the portion of the road within the NWR. The total and incremental cancer risks for the U.S. FWS staff member, derived by use of California Environmental Protection Agency (Cal-EPA) toxicity criteria, were estimated at 3.2 x 10'7 and 2.7 x l0-7, respectively. The excess lifetime cancer risk to the U.S. FWS staff member was estimated to be below the NCP's point of departure of 10-6, and risks below this level can be interpreted as unconditionally acceptable. Similarly, the total and incremental cancer risks for the Navy security guard patrolling the road (AOPC IR through 10R) were estimated at 9.2 x 10-6 and 3.5 x 10-6, respectively. The excess lifetime cancer risk to the Navy security guard patrolling the road was quantified to be within the NCP's generally acceptable risk range (l06 to 104). Cancer risk is principally associated with arsenic. Inhalation of particulate matter generated by the vehicle was the dominant risk pathway. Although the risk to the Navy security guard patrolling the road is also applicable to the rest of the perimeter road (AOPCs 2R through 10R), it will not be repeated under the risk conclusions for AOPCs 2R through IOR at IRP Site 4, but should be considered in risk evaluations for these AOPCs. Results of the HHRA indicate that the HI value for the U.S. FWS staff member exposed to soil at AOPC IR and the Navy security guard patrolling the road are less than 1.0, indicating that systemic toxicity is unlikely. The risk for exposure to lead in soil is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Exposure to lead was assessed under the industrial scenario. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both scenarios. Although the HI and the risk for exposure to lead with respect to the Navy ) security guard patrolling the road are also applicable to the rest of the perimeter road page ES-6 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 679/2000 B 16 AM ttn\1Wos0010vnorwsikwvylbnno151 vse orefliprese tIo nuerrsec '^-c3.Oa CLEAN H CTO-015110197 Date 0622100 EXECUTIVE SUMMARY (continued) (AOPCs 2R through 1OR), they will not be repeated under the risk conclusions for AOPCs 2R through IOR at IRP Site 4, but should be considered in risk evaluations for these AOPCs. Based on the findings and conclusions for soil at AOPC 1R, soil is recommended for no further action. The total cancer risk for soil is below or within the NCP's target risk range and the HI is less than 1. AOPC 2R — SOIL Two PAHs, benzo(a)pyrene and benzo(b)fluoranthene, were reported at elevated concentrations in soil. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 7 of the 18 samples, all of which were in 0- to 1-foot- bgs samples. Two PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.1 mg/kg. Lead was the only metal with concentrations reported above statistical background (9 of 18 samples). Four samples had elevated lead concentrations reported, all at 0 to 1 foot bgs. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.8 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The estimated concentrations of lead in the blood of the resident child (10.6 to 13.4 pg/dL at 95th to 99th percentiles, respectively) slightly exceed the lead concentration of concern of 10 µg/dL, indicating the potential adverse health effects from exposure to lead at AOPC 2R. However, the residential scenario assumed for the AOPC is highly improbable. Based on the findings and conclusions for soil at AOPC 2R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range; the HI is less than 1; and blood lead concentrations slightly exceed 10 pg/dL, but are based on the highly improbable residential scenario assumption. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-7 619,2000 6 16 AM tm\\141o40010 norwaikwsvyiDncto151vse Oraltoresect,onoext%e:ecsum-0 Ooc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) AOPC 3R — SOIL Phenanthrene was the only PAH reported at concentrations above detection limits in soil. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 16 samples. Two PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.07 mg/kg. Antimony and lead were reported at concentrations above statistical backgrounds for these metals. Of these metals, antimony was not reported at concentrations above the geochemical background. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.6 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 104. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 3R is considered negligible based on the results of the •• Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Based on the findings and conclusions for soil at AOPC 3R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. AOPC 4R — SOIL Four PAHs were reported at concentrations above detection limits in the soil samples. The PAH with the highest frequency of detection was phenanthrene. Total 2,3,7,8- TCDD-equivalent concentrations were reported above the residential PRG value in 6 of the 17 samples. Two PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.06 mg/kg. Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, copper, lead, thallium, and hexavalent chromium. Of these metals, antimony, chromium, copper, and thallium were not reported at concentrations above the geochemical background. An elevated lead concentration was reported in one sample. page ES-8 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA /162000 a le AM tm Asoos00lOworwiikvwvytbC1o1511rse ctrevresecnorwe,me■ecsuR*o ooc CLEAN II CTO-015110197 Date 06/22/00 EXECUTIVE SUMMARY (continued) A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 9.8 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.091, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 4R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg'dL. Based on the findings and conclusions for soil at AOPC 4R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. AOPC 5R — SOIL Nine PAHs were reported at concentrations above detection limits in the soil samples. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 16 samples. Aroclor 1260 was the only PCB reported above detection limits in one sample. Metals reported at concentrations above statistical background consisted of antimony, cobalt, lead, mercury, thallium, and hexavalent chromium. Of these metals, antimony and thallium were not reported at concentrations above the geochemical background. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 1.9 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with Aroclor 1260. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.21, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-9 6/19.2000 8 18 AM Im tiOos0o10vwrweikV avyl0/cto151Vse OratnpreseclonUexne■ecsum-O.Ooc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 5R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 p.g/dL. Based on the findings and conclusions for soil at AOPC 5R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. AOPC 6R — SOIL One PAH, benzo(a)pyrene, was reported at an elevated concentration in one soil sample. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 6 of the 19 samples. Two PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.06 mg/kg. Antimony, arsenic, cobalt, and lead were reported at concentrations above statistical backgrounds. Of these metals, antimony was not reported at concentrations above the geochemical background. Arsenic was reported at elevated concentrations in three samples. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult • . residential receptor was estimated at 4.3 x 10-5, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be 2.2 x 10-5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.52, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 6R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 4g/dL. Based on the findings and conclusions for soil at AOPC 6R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. page ES-10 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/10.'2000 B 1B AM tm1lsdOS0010V10rwilkVYvylD\Ct01SIvs*oraftrecto,ltxllfxSGSum-C.000 CLEAN II CTO-0151/0197 Date 06'22.'00 EXECUTIVE SUMMARY (continued) AOPC 7R — SOIL Four PAHs were reported at concentrations above detection limits in the soil samples. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 18 samples. Aroclor 1260 was the only PCB reported above detection limits in one sample. Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver, thallium, and hexavalent chromium. Of these metals, antimony, chromium, silver, and thallium were not reported at concentrations above the geochemical background. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.1 x 10-5, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be 2.0 x 10-5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.96, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 7R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 .tg/dL. Based on the findings and conclusions for soil at AOPC 7R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range, and the HI is less than 1. AOPC 8R — SOIL Two PAHs, benz(a)anthracene and benzo(a)pyrene, were reported at elevated concentrations in the soil samples. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 5 of the 26 samples. Two PCBs were reported at concentrations above detection limits, with maximum Aroclor 1254 concentrations of 0.05 mg/kg. Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver, and thallium. Of these metals, antimony, chromium, silver, and thallium were not reported at concentrations above the geochemical background. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-1 1 6'19.2000 8 18 AM tm\zOof00101norwalkV4vylbcto151 V7e Ore1Creyect,on\aect,eaecsum-0 COC CLEAN II CTO-0151/0197 Date.06/72/00 EXECUTIVE SUMMARY (continued) A fate and transport evaluation, conducted for soil COPCs, indicated that none of the • COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.7 x 10-5, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with benzo(a)pyrene. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.24, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 8R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 101..1g/dL. Based on the findings and conclusions for soil at AOPC 8R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. AOPC 9R — SOIL One PAH, benzo(a)pyrene, was reported at an elevated concentration in the soil samples. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 12 of the 22 samples, 10 of which were in 0- to 1-foot-bgs samples. Three PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.09 mg/kg. Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver, thallium, and hexavalent chromium. Of these metals, antimony, chromium, silver, and thallium were not reported at concentrations above the geochemical background. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 1.3 x 10-5, which is within the NCP's generally acceptable risk range of Ie to I0-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with benzo(a)pyrene. The incidental soil ingestion pathway was the main contributor to residential risk. page ES-12 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/19/2000 8 16 AM tm\tsoos001 OMorwa* \navylo\c1o151 vse ora eesectwnutctic:ecs m6 ooc CLEAN II CTO-0151/0197 Date 06/22100 EXECUTIVE SUMMARY (continued) The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.39, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 9R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Based on the findings and conclusions for soil at AOPC 9R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. AOPC 1 OR — SOIL Seven PA.Hs were reported at concentrations above detection limits in the soil samples. Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 7 of the 18 samples, all of which were in 0- to 1-foot-bgs samples. Two PCBs were reported at concentrations above detection limits, with a maximum Aroclor 1254 concentration of 0.04 mg/kg. Metals reported at concentrations above statistical background consisted of antimony, barium, cadmium, chromium, cobalt, copper, lead, mercury, zinc, and hexavalent chromium. Of these metals, antimony, barium, chromium, copper, and zinc were not reported at concentrations above the geochemical background. Cadmium was the only metal reported at elevated concentrations. A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. Results of the HHRA indicate that the total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 3.5 x 10.5, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be 1.4 x 10-5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.81, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC IOR is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-13 6/1 912000 8 18 AM In,Ntdot00101norwalkV avylb\c1O151 Vse dnfi,presecuonVext execturr.d Ooc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) Based on the findings and conclusions for soil at AOPC 10R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. IRP SITE 5 - CLEAN FILL DISPOSAL AREA IRP Site 5 is an approximately 4.1-acre area situated in the southwest quadrant of the facility, near the southeast corner of Kitts Highway and Bolsa Avenue. Approximately 3.3 acres of this site are covered with disposal fill materials. IRP Site 5 is located within the boundaries of the NWR (Figure ES-5). In 1944, during the initial construction of WPNSTA, Seal Beach, construction debris and clean fill were disposed in this area. During the initial assessment study site visit, the site was observed to be approximately 3 feet above the adjacent salt marsh and was covered with vegetation (NEESA 1985). Unexploded ordnance (UXO) was reportedly found at this site, and trucks had been observed in the past off-loading ordnance related material such as shell casings mixed with construction debris. Soil, sediment, and groundwater samples were collected and analyzed to characterize and delineate the lateral and vertical extent of COPCs. Sampling locations are shown on Figure ES-5. Discussion of the RSE investigation for IRP Site 5 soils, sediments, and groundwater is presented below. SOIL Because of the potential presence of UXO at IRP Site 5, a UXO survey and exploratory pit excavations were conducted. The UXO survey indicated the presence of scattered live UXO, ordnance explosive wastes, and scrap metals on the ground surface as well as at depth within the disposal fill area. The UXO survey concluded that additional uninvestigated magnetic anomalies exist at IRP Site 5 and that UXO may still be present. A radiation walkover survey was also conducted at the site. Results of a radiological survey performed at IRP Site 5 indicated that exposure rates within the disposal area were well within the background range (areas surrounding the disposal fill area). A statistical comparison of the data indicated that the background population was the same as the IRP Site 5 population. Soil samples were collected from hand-auger borings within the disposal fill area at depth intervals of 0.5 to 1.0 and 4.5 to 5.0 feet bgs and from three exploratory pits excavated within the disposal fill. The soil samples were analyzed for nitrate, ammonia, volatile organic compounds (VOCs), explosives, semivolatile organic compounds (SVOCs), PAHs, PCBs, TAL metals, and hexavalent chromium. Samples collected from the soil borings and exploratory pits indicate that the fill materials encountered in the disposal fill area (or IRP Site 5 boundary) consist predominantly of various shades of brown and gray silt, sand, and sand-silt mixtures with lesser amounts of clay, construction debris, scrap metal, page ES-14 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6119(2000 8 18 AM tm\\sdOtOC 101qnglk W vyl b\Ct01 51 vitt ctraft V esect,cruernexecSum-o COC CLEAN II CTO-0151/0197 Date 06,22/00 EXECUTIVE SUMMARY (continued) ordnance explosive wastes, UXO, and other miscellaneous debris. Underlying the fill materials are Recent deposits. Eleven VOCs were reported at concentrations above detection limits in the soil samples. Three samples had SVOC (other than PAHs) concentrations reported above detection limits. PAHs reported at elevated concentrations consist of benzo(a)pyrene, benzo(b)fluoranthene, and dibenz(a,h)anthracene, mostly in surface samples (0.5 to 1 foot bgs). Nitroaromatics/nitramines were not reported at concentrations above detection limits in any of the soil samples. Aroclor 1254 and Aroclor 1260 were reported at concentrations above detection limits. Eight metals (antimony, arsenic, cadmium, chromium, cobalt, copper, lead, and zinc) and hexavalent chromium were reported above statistical background in soil. Of these metals, arsenic and chromium were not reported at concentrations above the geochemical background. A fate and transport evaluation to ascertain whether COPCs in soil at IRP Site 5 represent a potential future threat to groundwater was conducted for soil COPCs. Results indicated that anthracene, fluorene, phenanthrene, copper, and ammonia could affect groundwater at the site above the groundwater screening criteria but that none of the COPCs would affect groundwater at a hypothetical point of discharge into the marine environment, located 250 feet from the site. Results of the HHRA indicate that the total and incremental excess lifetime cancer risks, derived by Cal-EPA carcinogenic toxicity criteria, for the U.S. FWS habitat restoration maintenance supervisor and U.S. FWS tour guide exposed to soils and volatile compounds originating from the groundwater were estimated within the NCP's target risk range for health protectiveness (10-6 to 10-4) at 3.7 x 10-6 and 8.2 x 10-6, respectively. The majority of the risk is associated with benzo(a)pyrene in soil. At IRP Site 5, benzo(a)pyrene was characterized with an 84 percent detection frequency and a lognormal distribution. The HI associated with exposure to an U.S. FWS habitat restoration/maintenance supervisor and U.S. tour guide exposed to soil at the site is less than 1.0, indicating that systemic toxicity is unlikely. The risk for exposure to lead by the U.S. FWS habitat restoration/maintenance supervisor was estimated based on exposures to an industrial worker. Under the industrial scenario, the risk for exposure to lead in soil at IRP Site 5 is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Results of the ERA indicate that the potential for ecological risk at this site appears quite low (HQ less than 1) based on comparisons to toxicity references values and stationwide background values. Based on the results and conclusions of the radiation survey, the HHRA, and the ERA, no further action is recommended for the soils of IRP Site 5. However, based on the results Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-15 6/1&2000 8 18 AM tm Nsoos0010vwrwaikvuvytc/cto151vse oraft4aresect.onuext*xec$urno.0oc CLEAN II CTO-0151/0197 Date.06/22/00 EXECUTIVE SUMMARY (continued) of the UXO survey, it is recommended that the potential for UXO presence at the site be further evaluated and any UXO identified by this evaluation be removed from the site. SEDIMENT Sediment samples were collected from the salt marsh area, around the perimeter of the disposal fill area. Sediment samples were generally collected at a depth interval of 0.5 to 1.0 foot bgs. Sediment samples were analyzed for PAHs, PCBs, and TAL metals. Sediment samples consisted predominantly of various shades of brown and gray to black clay and silt, with lesser amounts of silty sand and sand. PAHs and PCBs were reported at concentrations above detection limits in the sediment samples. Nine metals (arsenic, cadmium, cobalt, copper, lead, nickel, selenium, vanadium, and zinc) and hexavalent chromium were reported above statistical background in sediment samples collected around the perimeter of IRP Site 5. Of these metals, arsenic, copper, and zinc were not reported at concentrations above the geochemical background. A fate and transport evaluation, conducted for sediment COPCs, indicated that ammonia may affect groundwater at the site above the groundwater screening criteria but would not affect groundwater at a hypothetical point of discharge into the marine environment, located 250 feet from the site. ) The area surrounding IRP Site 5 is a salt marsh. As a result, the potential risk to human health is not a concern; therefore, only potential risks to ecological receptors were evaluated. Sediment samples evaluated at IRP Site 5 were actually collected from the salt marsh area just beyond the site boundary. The findings of the ERA indicate that none of the COPECs likely represent a potential ecological risk to estuarine sediment invertebrates in the salt marsh habitat. Based on the results and conclusions of the fate and transport evaluations and the ERA, no further action is recommended for the sediments adjacent to IRP Site 5. GROUNDWATER Groundwater is present at a depth of approximately 5 feet bgs beneath IRP Site 5. Results of a tidal survey conducted in the vicinity of the site indicate that groundwater elevations beneath IRP Site 5 are influenced by the tides. The shallow groundwater flow direction in the vicinity of IRP Site 5 is toward the east-northeast with an overall gradient of approximately 0.0001. The anion and cation concentrations and the TDS data suggest that the shallow groundwater beneath IRP Site 5 is brackish to saline in nature. Groundwater samples were collected from temporary well-points and monitoring wells and analyzed for explosives, VOCs, SVOCs, PAHs, PCBs, TAL metals, hexavalent chromium, and general groundwater chemistry. VOCs or SVOCs were not reported at concentrations above the COP WQO or U.S. EPA AWQC for saltwater in any of the groundwater samples collected at IRP Site 5. Four PAHs, benzo(a)pyrene, page ES-16 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 611 Dr?000 a le AM tin 11s0060010vtt7rwslkwvylb1Ct0151 vie OriflVW.SICuonutw/aeCsum-O 000 CLEAN II CTO-0151/0197 Date 05'2200 EXECUTIVE SUMMARY (continued) benzo(g,h.i)perylene, fluoranthene, and pyrene, were reported above detection limits in a groundwater sample. The concentrations for benzo(a)pyrene, benzo(g,h,i)perylene, and pyrene exceed the COP WQO for human health (30-day average) for total PAHs. PCBs were not reported above the detection limits. 1,3-Dinitrobenzene was reported above detection limit in one out of the seven-groundwater samples analyzed for nitroaromatics and nitramines. No COP WQO or U.S. EPA AWQC for saltwater exists for 1,3-dinitrobenzene. Ten metals (antimony, arsenic, barium, cadmium, cobalt, copper, manganese, selenium, vanadium, and zinc) and hexavalent chromium were reported above detection limits in groundwater samples. Of the ten metals, four metals (antimony, cobalt, manganese, zinc) and hexavalent chromium were reported at concentrations above statistical background. No COP WQO or U.S. EPA AWQC for saltwater exists for cobalt or manganese. None of the antimony concentrations were reported above the COP WQO for human health (30-day average). Zinc and hexavalent chromium concentrations were reported above the COP WQO (6-month median) concentrations; however, these concentrations were below the U.S. EPA AWQC for saltwater concentrations. A fate and transport evaluation, conducted for groundwater COPCs, indicated that hexavalent chromium, manganese, ammonia, and nitrate could continue to affect groundwater above the groundwater screening criteria at the site for 50 years. However, only ammonia significantly exceeds the groundwater screening criteria. Furthermore, the simulations indicate that groundwater at a hypothetical point of discharge into the marine environment, located 250 feet from the AOPC would not be affected. Results of the ERA indicate that potential effects to general marine life are low, based on comparing measured groundwater COPEC concentrations to water quality criteria. Six compounds exceeded the water-quality criteria: antimony (HQ of 4.0), arsenic (HQ of 3.0), hexavalent chromium (HQ of 2.5), cobalt (HQ of 1.5), zinc (HQ of 2.5), and diethyl phthalate (HQ of 1.2). However, it is unlikely that marine life would be adversely affected at these levels. Based on the results and conclusions of fate and transport evaluations, the HHRA, and the ERA, the groundwater of IRP Site 5 is recommended for no further action. IRP SITE 6 - EXPLOSIVES BURNING GROUND IRP Site 6 is located approximately 500 feet northwest of the station landfill (IRP Site 7), near the south-central portion of WPNSTA, Seal Beach. IRP Site 6 is located within the boundaries of the NWR (Figure ES-6). This investigation found IRP Site 6 covered an area of approximately 16.8 acres. From 1944 to 1971, this area was used for open burning of waste ordnance and materials used during fire training exercises. The open burning was conducted in either a trench or • on an unlined shallow pad. The enactment of air-quality regulations, along with • complaints from citizens living in the adjacent community, resulted in a self-imposed ban Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-17 6'19,2000 8 18 AM im\a,aos0010wonweikwvyitncto151 se araft\presec1 o eK1 xresumE ooc CLEAN II CTO-0151/0197 Date:06,'22/00 EXECUTIVE SUMMARY (continued) on open burning by 1970, except for emergency disposal (NEESA 1985 and SWDIV 1990). A geophysical survey was conducted at 1RP Site 6 in an attempt to locate the former burn trenches. Vertical magnetic gradient and electromagnetic terrain conductivity surveys were performed to locate the former burn trenches. The electromagnetic terrain conductivity survey was found to be of limited usefulness in identifying buried burn trenches and pits because of the highly conductive nature of the 1RP Site 6 soils. The vertical magnetic gradient survey identified eight areas with anomalous readings; however, only three of these had readings consistent with that of a buried trench or pit. The geophysical anomalies were then investigated by a series of trenches, test pits, and hand-auger soil borings. Soil and groundwater samples were collected and analyzed to characterize and delineate the lateral and vertical extent of COPCs. Sampling locations are shown on Figure ES-6. Discussion of the RSE investigation for IRP Site 6 soils (AOPCs 1N, 1S, and 2) and groundwater is presented below. AOPC 1N — SOIL Former burn trench locations, tentatively identified by the geophysical survey and subsequently confirmed by trenching and logging, were sampled. Soil samples were collected from the side walls of four trenches excavated to an approximate depth of 4 feet bgs, with approximate lengths ranging between 92 to 268 feet. Six exploratory pits, consisting of potholes to depths ranging between 2.5 to 4.0 feet bgs, were excavated to supplement the trenching performed at IRP Site 6. The purpose of the exploratory pits was to assess the nature and extent of waste fill identified in three of the trenches and investigate specific geophysical anomalies. Soil samples were generally collected from the side walls of four trenches excavated to an approximate depth of 4 feet bgs with approximate lengths ranging between 92 to 268 feet. Six exploratory pits, consisting of potholes to depths ranging between 2.5 to 4.0 feet bgs, were excavated to supplement the trenching performed at IRP Site 6. The purpose of the exploratory pits was to assess the nature and extent of waste fill identified in three of the trenches and to investigate specific geophysical anomalies. Soil samples collected from the trenches indicate that the waste fill on the northern portion of AOPC 1N consists predominantly of black to dark brown silt with wood timbers, rubber, rusted metal fragments, and miscellaneous debris. Underlying the fill materials are the Recent deposits. Soil samples were collected at 0.5 feet bgs (upper interval samples) and 2 feet bgs (lower interval sample). Soil samples were generally analyzed for SVOCs, PAHs, PCBs, TAL metals, and ammonia. Select samples were analyzed for nitroaromatics.!nitramines and nitrate. Soil samples collected at the lower sample interval of 2.0 feet bgs were also analyzed for VOCs. page ES-18 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 8/19/2000 8.18 AM tm\KOos0010Y\awolkvwvylb\c1o151vse Onflvxesecuon1 extwxecwm-d doc CLEAN II CTO-0151/0197 Date: 06-22100 EXECUTIVE SUMMARY (continued) Acetone and methylene chloride were the only VOCs reported at concentrations above detection limits. No SVOCs, other than PAHs, which are discussed below, were reported above detection limits in the soil samples analyzed for SVOCs. Thirteen of the 16 PAHs were reported above detection limits. PCBs and nitroaromatics/nitramines were not reported at concentrations above detection limits in any of the soil samples analyzed. Ammonia values for soil in AOPC 1N ranged from less than 0.2 to 1.2 mg/kg. The concentration of nitrate is less than the stationwide statistical background value. Six metals (antimony, cobalt, copper, lead, silver, and thallium) and hexavalent chromium were reported at concentrations above statistical background. Of these metals, antimony, silver, and thallium were not reported at concentrations above the geochemical background and only copper was reported at a concentration greater than the geochemical background (88.6 mg/kg). A fate and transport evaluation, conducted for soil COPCs, indicated that none of the COPCs would affect groundwater above the groundwater screening criteria at the AOPC or a hypothetical point of discharge into the marine environment, located some 400 feet from the AOPC. Results of the HHRA indicate that the total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria to a U.S. FWS habitat restoration/maintenance supervisor and to a U.S. FWS tour guide at AOPC IN were estimated below the NCP's point of departure (10-6). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 4.3 x 10-7 and 9.5 x 10-7, respectively. The HI associated with exposure to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC 1N is estimated at less than 1.0. HI estimates below unity indicate that systemic toxicity is unlikely for the U.S. FWS staff. The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both receptors. Results of the ERA indicate that the potential for ecological risk at this AOPC appears quite low based on comparisons to TRVs and stationwide statistical background values. Based on the results of the HHRA indicating that the maximum cancer risk under the assumed scenarios is less than NCP's point of departure (10-6) and the H1 is less than 1, along with the ERA indicating low potential ecological risks, no further action is recommended for the soil of AOPC 1N. AOPC 1S — SOIL Soil samples were collected from hand-augered soil borings at depth intervals of approximately 0.5 and 2 feet bgs. Soil samples collected from the soil borings suggest that fill material covers much of AOPC IS, and the composition of the fill material is Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-19 6/142000 8 18 AM trn 140o$0010vtorwinkvuvytb%ct0151 Vtte Oraflpe$e onVexiNexecsagn-0 CLEAN II CT 0-0151/0197 Date.06/22/00 EXECUTIVE SUMMARY (continued) slightly different from that observed on AOPC 1N. The fill on AOPC 1S appears to consist predominantly of dark olive-brown to dark grayish-brown silt with traces of wood fragments, decaying organic material, rusted metal fragments, clay, pea gravel, plastic fragments, and concrete debris. Underlying the fill materials are the Recent deposits. Soil samples were generally analyzed for SVOCs, PAHs, PCBs, and TAL metals. Select soil samples were analyzed for ammonia, nitroaromatics/nitramines, nitrate, and hexavalent chromium. Lower interval soil samples were also analyzed for VOCs. Nineteen samples had VOC concentrations reported above detection limits. Bis(2-ethylhexyl)phthalate and di-n-butyl phthalate were the only SVOCs reported above detection limits. Four PAHs, benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, and dibenz(a,h)anthracene, were reported at elevated concentrations. PCBs reported above detection limits consisted of Aroclor 1242, Aroclor 1254, and Aroclor 1260. 2,4-Dinitrotoluene and n-nitrosodiphenylamine were reported at concentrations above detection limits. Ten metals (antimony, arsenic, chromium, cobalt, copper, lead, silver, selenium, thallium, and zinc) and hexavalent chromium were reported at concentrations above statistical background. Of these metals, antimony, chromium, copper, silver, thallium, and zinc were not reported at concentrations above the geochemical background. Arsenic (one sample) and lead (one sample) were reported at elevated concentrations. Reported ammonia values for soil samples collected from AOPC 1S • ranged from less than 0.06 to 8.1 mg/kg. • A fate and transport evaluation, conducted for soil COPCs, indicated that anthracene, phenanthrene, and ammonia may affect groundwater above the groundwater screening • criteria at AOPC IS. However, at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC, only ammonia affected groundwater above the screening criteria. Results of the HHRA indicate that the total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria, to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC IS were estimated below the NCP's point of departure (10-6). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 2.3 x 10'7 and 5.0 x 10-7, respectively. The HI associated with exposure to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC 1S is estimated at less than 1.0. HI estimates below unity indicate that systemic toxicity is unlikely for the U.S. FWS staff. The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both receptors. page ES-20 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 61962000 a 115 AM tm 11.0os0010 norwalkwvylt)\ct0151 vu W7nypresecuomtexne.ec urn0.000 CLEAN II CTO-015110197 Date 06.'22100 EXECUTIVE SUMMARY (continued) Results of the ERA indicate that the potential for ecological risk at this AOPC appears quite low based on comparisons to TRVs and stationwide statistical background values. Based on the results of the HHRA indicating that the maximum cancer risk under the assumed scenarios is less than NCP's point of departure (10') and the HI is less than 1, along with the ERA indicating low potential ecological risks, no further action is recommended for the soil of AOPC 1S. AOPC 2 — SOIL Soil samples were collected from hand-augered soil borings generally at depth intervals of 0.5 and 2 feet bgs. Soil samples collected from the soil borings suggest that AOPC 2 is entirely underlain by Recent deposits. Soil samples were generally analyzed for SVOCs, PAHs, PCBs, TAL metals, and ammonia. Select samples were analyzed for nitroaromatics!nitramines, hexavalent chromium, and nitrate. Lower interval samples were also analyzed for VOCs. Only one sample had VOC concentrations reported above detection limits. Di-n-butyl phthalate was the only SVOC reported at a concentration above detection limit. PAHs were reported above detection limits, with indeno(1,2,3-cd)pyrene reported with the highest frequency of detection. The explosives 2,4-dinitrotoluene, 2,6-dinitrotoluene, and n-nitrosodiphenylamine were reported at concentrations above detection limits. The PCBs Aroclor 1248 and Aroclor 1260 were reported at concentrations above detection limits. Ammonia values for soil samples collected from AOPC 2 ranged from less than 0.2 to 3.3 mg/kg. Three metals (cobalt, lead, and zinc) were reported at concentrations above statistical background. Zinc was reported at a concentration above the geochemical background in one sample. A fate and transport evaluation, conducted for soil COPCs, indicated that ammonia may affect groundwater above the groundwater screening criteria at AOPC 2 and at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC. Results of the HHRA indicate that the total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria, to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC 2 were estimated below the NCP's point of departure (l 0-6). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 4.7 x 104 and 1.0 x 10-7, respectively. The HI associated with exposure to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC 2 is estimated at less than 1.0. HI estimates below unity indicate that systemic toxicity is unlikely for the U.S. FWS staff. The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-21 6,19.2000 8 18 AM trn\4Oos0010vwnoIkWvy1d\ct0151 use O1iry\presecyionuextwxecsurn-0 doc CLEAN II CTO-0151/0197 Date:06/22/00 EXECUTIVE SUMMARY (continued) • concentrations are below the lead concentration of concern of 10 p.g/dL for both receptors. Results of the ERA indicate that lead showed an HQ value exceeding 1 (HQ of 12) for the robin, which was used to represent omnivorous birds, with the primary exposure pathway for lead being through incidental ingestion of soil. However, after comparing these values to background conditions and to the range of TRVs, they did not appear ecologically significant. The HHRA indicated that the maximum cancer risk under the assumed scenarios is less than NCP's point of departure (10-6) and the HI is less than 1, and the ERA has indicated a low potential for ecological risk. AOPC 2 is, therefore, recommended for no further action. GROUNDWATER Groundwater samples were collected from temporary well-points and monitoring wells and were generally analyzed for VOCs, SVOCs, PAHs, PCBs, nitroaromatics/nitramines, TAL metals, hexavalent chromium, perchlorates, and general groundwater chemistry. Groundwater is present at a depth of approximately 5 feet bgs at the site. Results of a tidal survey indicated that groundwater elevations beneath the site are influenced by the tides. The shallow groundwater flow direction for IRP Site 6 (and vicinity) is toward the east-northeast with an overall gradient of approximately 0.002. The apparent flow direction at IRP Site 6 may be attributed to the closeness of the pond and channelways in the NWR located to the south-southwest portions of the site. The detected anion and cation concentrations and the reported TDS values suggest that the shallow groundwater beneath IRP Site 6 is saline in nature. Three VOCs (carbon disulfide, chloromethane, and methyl tert-butyl ether [MTBE]) were reported at concentrations above detection limits in IRP Site 6 groundwater samples. Chloromethane was not reported at concentrations above the COP WQO or U.S. EPA AWQC for saltwater in any of the groundwater samples collected at IRP Site 6. No COP WQO or U.S. EPA AWQC for saltwater exists for carbon disulfide or MTBE. 4-Chloro- 3-methylphenol was the only SVOC reported at a concentration above detection limit only in one groundwater sample. This concentration was below the COP WQO 6-month median. Two PAHs, fluoranthene and pyrene, were reported above detection limits only in the groundwater sample. The concentration for pyrene exceeds the COP WQO for human health (30-day average) for total PAHs. Of the seven PCBs groundwater samples were analyzed for, none were reported above detection limits in IRP Site 6 groundwater samples. Only 1,3-dinitrobenzene was reported above detection limit in one out of the eight groundwater samples analyzed for nitroaromatics and nitramines at IRP Site 6. No COP WQO or U.S. EPA AWQC for saltwater exists for 1,3-dinitrobenzene. Of the five groundwater samples collected at IRP Site 6 and analyzed for perchlorates, none had perchlorate concentrations reported above detection limits. page ES-22 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/19.2000 6 16 AM Vn\\s405001 oworniikv,.vyib\cxo151vse or.fllpresecl,onvexriexecsum4.clot CLEAN II C70-0151/0197 Date 06/22/00 EXECUTIVE SUMMARY (continued) Twelve metals (antimony, arsenic, barium, cadmium, cobalt, copper, lead, manganese, nickel, selenium, vanadium, and zinc) and hexavalent chromium were reported above detection limits in groundwater samples collected from IRP Site 6. Of the 12 metals, 8 metals (antimony, cadmium, cobalt, copper, lead, manganese, nickel, and zinc) and hexavalent chromium were reported at concentrations above statistical background. Antimony concentrations were below the COP WQO for human health (30-day average). Cadmium, copper, nickel, and zinc concentrations were above the COP WQO 6-month median concentration and the U.S. EPA AWQC for saltwater concentration. Lead and hexavalent chromium concentrations were above the COP WQO 6-month median but below the U.S. EPA AWQC for saltwater. No COP WQO or U.S. EPA AWQC for saltwater exists for cobalt or manganese. A fate and transport evaluation, conducted for groundwater COPCs, indicated that pyrene. hexavalent chromium, cobalt, copper, lead, nickel, and zinc could continue to affect groundwater above the groundwater screening criteria at IRP Site 6 for 50 years. However, only copper and zinc significantly exceed the groundwater screening criteria at the site. Furthermore, the simulations indicate that only ammonia might affect groundwater at a hypothetical point of discharge into the marine environment, located 100 feet from the site; ammonia concentrations at the site after 50 years are negligible because of transport away from the site. Results of the ERA indicate that eight compounds in groundwater exceeded the water quality criteria: ammonia (HQ of 3.0), antimony (HQ of 3.0), cadmium (HQ of 18), hexavalent chromium (HQ of 2.1), cobalt (HQ of 1.6), lead (HQ of 2.5), nickel (HQ of 6.9), and zinc (HQ of 132). A potentially complete exposure pathway was assumed between Site 6 AOPC 2 groundwater and aquatic ecological receptors because groundwater is shallow and surface water ponds are in close proximity. The potential exists for the groundwater to mix with surface water in the estuary and thereby expose aquatic organisms to contaminants identified in the groundwater. If marine organisms are exposed to groundwater, cadmium, nickel, and zinc may represent a risk to sensitive marine life. Based on groundwater fate and transport simulations, it is unlikely that marine organisms would be exposed to deleterious concentrations of these metals as a result of groundwater at this site. Based on the conclusions of fate and transport evaluations, the HHRH and the ERA, the groundwater of IRP Site 6 is recommended for no further action. REFERENCES A.T. Kearney, Inc. 1989. Resource Conservation and Recovery Act Facility Assessment, Naval Weapons Station, Seal Beach, California. Bechtel National Inc. 1998. Final Removal Site Evaluation Work Plan, Installation Restoration Sites 4, 5, and 6. Weapons Support Facility, Seal Beach, California. October. BN1. See Bechtel National Inc. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page ES-23 6/19.2000 8 18 AM im wios0010v)orwaikVuvy1D\C10151Vse Orinlpresecionuex14:ecsurr-0.000 CLEAN II CTO-0151/0197 Date 06/22/00 EXECUTIVE SUMMARY (continued) Kearney. See A.T. Kearney, Inc. Naval Energy and Environmental Support Activity. 1985. Initial Assessment Study, Naval Weapons Station, Seal Beach, California. NEESA 13-062. February. NEESA. See Naval Energy and Environmental Support Activity. Regional Water Quality Control Board, Central Valley Region. 1998. A Compilation of Water Quality Goals. California Environmental Protection Agency. March. RWQCB, Central Valley Region. See Regional Water Quality Control Board, Central Valley Region. Southwest Division Naval Facilities Engineering Command. 1990. Site Inspection (SI) Report, Naval Weapons Station, Seal Beach, California. Final Volume I. Technical Report. October. State Water Resource Control Board. 1997. California Ocean Plan. Water Quality Control Plan, Ocean Waters of California. California Environmental Protection Agency. 23 July. SWDIV. See Southwest Division Naval Facilities Engineering Command. SWRCB. 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( '.1 // \ \. lI i . _J �� '--- _ J • ) - - - .a..61.1.. h CLEAN II CTO-015110197 Date: 06'22100 TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY ES-1 ACRONYMS/ABBREVIATIONS xxiii 1 INTRODUCTION 1.1 Purpose 1-1 1.2 Regulatory Status 1-1 1.3 Operable Unit Designation 1-2 1.4 Report Preparation 1-2 1.5 Report Organization 1-3 2 SITE BACKGROUND 2.1 Facility Location and History 2-1 2.1.1 IRP Site 4: Perimeter Road 2-2 2.1.2 IRP Site 5: Clean Fill Disposal Area 2-2 2.1.3 IRP Site 6: Explosives Burning Ground 2-2 2.2 Summary of Previous Investigations 2-4 2.2.1 IRP Site 4: Perimeter Road 2-5 2.2.2 IRP Site 5: Clean Fill Disposal Area 2-7 2.2.3 IRP Site 6: Explosives Burning Ground 2-8 3 PHYSICAL CHARACTERISTICS OF THE STUDY AREA 3.1 Regional Setting and Topography 3-1 3.2 Geology 3-1 3.2.1 Regional Geologic Setting 3-1 3.2.2 Stratigraphy 3-2 3.2.2.1 Recent Deposits 3-3 3.2.2.2 Lakewood Formation 3-3 3.2.2.3 San Pedro Formation 3-3 3.3 Regional Hydrology 3-3 3.3.1 Water Supply 3-3 3.3.2 Surface-Water Hydrology 3-4 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page i 6/19/2000 9 18 am tan ttsOes00/0WOrwelk1levylOtGo151 Vse OI>1Mpttfel t,ontle*1vt Ir•toC•O OOC CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 3.4 Regional Hydrogeology 3-4 3.4.1 Groundwater Zones 3-5 3.4.2 Groundwater Flow Characteristics 3-6 3.4.3 Los Alamitos Barrier Project 3-6 3.4.4 Groundwater Levels,Use, and Quality 3-7 3.5 Soils 3-7 3.6 Demography and Land Use 3-8 3.7 Ecology 3-8 3.8 Climate 3-9 4 INVESTIGATION AND EVALUATION METHODS 4.1 Data Quality Objectives Process 4-1 4.2 Scoping 4-3 - 4.3 Field Data Collection and Sampling Activities 4-3 4.3.1 Aerial Photographic Review 4-4 4.3.2 Utility Clearance and Field Surveys 4-4 4.3.3 Soil Sampling 4-5 4.3.4 Cone Penetrometer Testing 4-5 4.3.5 Groundwater Sampling 4-6 4.3.5.1 Temporary Well-Point Sampling 4-6 4.3.5.2 Monitoring Well Installation,Development, and Sampling 4-6 4.3.6 Tidal Influence Survey 4-7 4.3.7 Field Screening for Explosives 4-7 4.3.8 Laboratory Analysis and Data Validation 4-8 4.3.9 Decontamination of Field Equipment 4-8 4.3.10 Investigation-Derived Waste Management and Disposal 4-8 4.3.11 Surveying 4-9 4.4 Work Plan Modifications 4-9 4.4.1 IRP Site 5 Sampling Grid 4-9 4.4.2 Locating Former Burn Trenches at 1RP Site 6 4-9 4.4.3 Splitting IRP Site 6, AOPC 1 into Two AOPCs 4-10 4.4.4 Sampling Wells W-38, W-39, and 06-MW-01 at IRP Site 6 4-10 4.4.5 Analysis of IRP Site 6 Groundwater Samples for Perchlorates 4-10 4.4.6 Analytical Method for Hexavalent Chromium 4-11 page ii Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA $/16/2000 621 pm tm n:lrtevyro1do151vse Oretp, bomte,rtvrstr•toc-0.0oc CLEAN II CTO-015110197 Date. 06/22/00 TABLE OF CONTENTS (continued) Section Page 4.4.7 Resampling Well W-40 for Zinc 4-11 4.4.8 Temporary Well-Point Sampling at IRP Site 4 4-11 4.4.9 Step-Out Soil Sampling at IRP Site 4 Accumulation Areas 4-11 4.4.10 Technical Changes to Human-Health Risk Assessment Work Plan 442 4.5 Data Reduction and Evaluation Methods 4-13 4.5.1 Database Management 4-13 4.5.2 Data Reduction 4-13 4.5.3 Data Evaluation Methods 4-14 4.5.3.1 Evaluation of Analytical Data from Previous Investigations 4-14 4.5.3.2 Geochemical Analysis of Metals 4-15 4.5.3.3 Descriptive Statistics 4-15 4.5.3.4 Comparison to Screening Criteria 4-16 4.5.3.5 Fate and Transport Analysis 4-17 4.5.3.6 Human-Health Risk Assessment 4-18 4.5.3.7 Ecological Risk Assessment 4-18 . 5 INVESTIGATION RESULTS 5.1 Geochemical Evaluation of Metals in Soil 5-1 5.2 Perimeter Road—IRP Site 4 5-3 5.2.1 RSE Field Investigation—IRP Site 4 5-3 5.2.1.1 Soil Sampling—IRP Site 4 5-3 5.2.1.2 CPT Soundings and Temporary Well-Point Sampling—IRP Site 4 5-4 5.2.2 Geological and Hydrogeological Findings— IRP Site 4 5-5 5.2.2.1 Geology, Hydrogeology, and Site Conceptual Model—IRP Site 4 5-5 5.2.2.2 Geotechnical Laboratory Results—IRP Site 4 5-7 5.2.2.3 Soil Chemistry—IRP Site 4 5-7 5.2.2.4 Groundwater Chemistry—IRP Site 4 5-9 5.2.3 Nature and Extent of Contamination—IRP Site 4 5-14 5.2.3.1 Sources of Contamination— IRP Site 4 5-14 5.2.3.2 Distribution of Contaminants in Soil —IRP Site 4 5-15 5.2.3.3 Distribution of Contaminants in Groundwater— IRP Site 4 5-27 Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page iii 6/19/2000 12 01 pm tmtvwos00t0worwsucvufvylovto1Stvse Orifi cssoctionucovratt•tOC-d.(a CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) 4 Section Page 5.2.4 Contaminant Fate and Transport—IRP Site 4 5-29 5.2.4.1 Contaminant Fate and Transport in Soil and Groundwater at AOPC 1 A—IRP Site 4 5-29 5.2.4.2 Contaminant Fate and Transport in Soil and Groundwater at AOPC 2A—IRP Site 4 5-30 5.2.4.3 Contaminant Fate and Transport in Soil at AOPC 1R—IRP Site 4 5-30 5.2.4.4 Contaminant Fate and Transport in Soil at AOPC 2R—IRP Site 4 5-31 5.2.4.5 Contaminant Fate and Transport in Soil at AOPC 3R—IRP Site 4 5-31 5.2.4.6 Contaminant Fate and Transport in Soil at AOPC 4R—IRP Site 4 5-32 5.2.4.7 Contaminant Fate and Transport in Soil at AOPC 5R—IRP Site 4 5-32 5.2.4.8 Contaminant Fate and Transport in Soil at AOPC 6R—IRP Site 4 5-32 5.2.4.9 Contaminant Fate and Transport in Soil at AOPC 7R—IRP Site 4 5-33 5.2.4.10 Contaminant Fate and Transport in Soil at AOPC 8R—IRP Site 4 5-33 5.2.4.11 Contaminant Fate and Transport in Soil at AOPC 9R—IRP Site 4 5-33 5.2.4.12 Contaminant Fate and Transport in Soil at AOPC l OR—1RP Site 4 5-34 5.2.5 Refined Conceptual Model and Summary of Nature and Extent—IRP Site 4 5-34 5.2.5.1 Refined Conceptual Model for AOPCs IR and 2R—1RP Site 4 5-34 5.2.5.2 Refined Conceptual Model for AOPCs IA and 2A—IRP Site 4 5-35 5.2.5.3 Refined Conceptual Model for AOPCs 3R Through l OR—IRP Site 4 5-38 5.3 Clean Fill Disposal Area—IRP Site 5 5-41 5.3.1 RSE Field Investigation—IRP Site 5 5-41 5.3.1.1 Aerial Photographic Interpretation—IRP Site 5 5-41 5.3.1.2 UXO Survey and Exploratory Pit Excavation— IRP Site 5 5-41 ) page iv Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/1912000 12:06 pm an n:WvyIDYxol51vs*Orernoraw:bonuMvmsvta-a.0oc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 5.3.1.3 Radiological Survey—1RP Site 5 5-42 5.3.1.4 Soil Sampling—IRP Site 5 5-42 5.3.1.5 Sediment Sampling—IRP Site 5 5-43 5.3.1.6 CPT Soundings and Temporary Well-Point Sampling—IRP Site 5 5-43 5.3.1.7 Monitoring Well Installation,Development, and Sampling—IRP Site 5 5-45 5.3.2 Geological and Hydrogeological Findings—IRP Site 5 5-45 5.3.2.1 Geology,Hydrogeology, and Site Conceptual Model—1RP Site 5 5-45 5.3.2.2 Geotechnical Laboratory Results—1RP Site 5 5-49 5.3.2.3 Soil Chemistry—IRP Site 5 5-49 5.3.2.4 Groundwater Chemistry—IRP Site 5 5-52 5.3.3 Nature and Extent of Contamination—IRP Site 5 5-56 5.3.3.1 Sources of Contamination—IRP Site 5 5-56 5.3.3.2 Distribution of Chemicals in Soil and Sediment—IRP Site 5 5-58 5.3.3.3 Distribution of Chemicals in Groundwater— IRP Site 5 5-62 5.3.4 Contaminant Fate and Transport—1RP Site 5 5-65 5.3.4.1 Contaminant Fate and Transport in Soil— IRP Site 5 5-65 5.3.4.2 Contaminant Fate and Transport in Sediment— IRP Site 5 5-65 5.3.4.3 Contaminant Fate and Transport in Groundwater—IRP Site 5 5-66 5.3.5 Refined Conceptual Model and Summary of Nature and Extent—IRP Site 5 5-66 5.3.5.1 Refined Conceptual Model for Soils— IRP Site 5 5-66 5.3.5.2 Refined Conceptual Model for Groundwater —TRP Site 5 5-68 5.4 Explosives Burning Ground—IRP Site 6 5-71 5.4.1 RSE Field Investigation—IRP Site 6 5-71 5.4.1.1 Aerial Photograph Interpretation 5-71 • Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page v 6/19/2000 12:02 pm tin 1lsoos0010vrorwaIklnaynp1ao151vae draftlpresecypmiex1Vrstr-toc-0.aoc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 5.4.1.2 Geophysical Survey of Subsurface Conditions— IRP Site 6 5-73 5.4.1.3 Trenches and Exploratory Pits—IRP Site 6 5-74 5.4.1.4 Soil Sampling—IRP Site 6 5-75 5.4.1.5 CPT Soundings and Temporary Well-Point Sampling—IRP Site 6 5-79 5.4.1.6 Monitoring Well Installation, Development, and Sampling—IRP Site 6 5-81 5.4.2 Geological and Hydrogeological Findings—IRP Site 6 5-81 5.4.2.1 Geology, Hydrogeology, and Site Physical Conceptual Model—IRP Site 6 5-81 5.4.2.2 Geotechnical Laboratory Results—IRP Site 6 5-87 5.4.2.3 Soil Chemistry—IRP Site 6 5-87 5.4.2.4 Groundwater Chemistry—IRP Site 6 5-90 5.4.3 Nature and Extent of Contamination—IRP Site 6 5-94 5.4.3.1 Sources of Contamination—IRP Site 6 5-94 5.4.3.2 Distribution of Contaminants in Soil —IRP Site 6 5-95 5.4.3.3 Distribution of Chemicals in Groundwater— IRP Site 6 5-100 5.4.4 Contaminant Fate and Transport— IRP Site 6 5-103 5.4.4.1 Contaminant Fate and Transport in Soil at AOPC 1N—IRP Site 6 5-103 5.4.4.2 Contaminant Fate and Transport in Soil at • AOPC 1S —IRP Site 6 5-104 5.4.4.3 Contaminant Fate and Transport in Soil at AOPC 2—IRP Site 6 5-104 5.4.4.4 Contaminant Fate and Transport in Groundwater—IRP Site 6 5-104 5.4.5 Refined Conceptual Model—IRP Site 6 5-105 5.4.5.1 Refined Conceptual Model for Soils of AOPC 1N—IRP Site 6 5-105 5.4.5.2 Refined Conceptual Model for Soils of AOPC 1S —1RP Site 6 5-106 5.4.5.3 Refined Conceptual Model for Soils of AOPC 2—IRP Site 6 5-108 5.4.5.4 Refined Conceptual Model for Groundwater— IRP Site 6 5-108 page vi Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/19/2000 12•04 pm tm Os0010V Cr sJkVlevy101t10151 Vtfe OrNilp/efeebOmiextvt v.IOc. . cc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 6 HUMAN-HEALTH AND ECOLOGICAL RISK ASSESSMENT 6.1 Human-Health Risk Assessment 6-1 6.1.1 Chemicals of Potential Concern 6-1 6.1.1.1 Data Evaluation Process 6-1 6.1.1.2 Soil Data 6-2 6.1.1.3 Groundwater Data 6-3 6.1.2 Exposure Assessment 6-3 6.1.2.1 Receptor Analysis 6-3 6.1.2.2 Exposure Settings 6-5 6.1.2.3 Exposure Pathways 6-5 6.1.2.4 Exposure-Point Concentration 6-7 6.1.2.5 Estimation of Dose Rate 6-10 6.1.3 Exposure Assumptions 6-11 6.1.4 Toxicity Assessment 6-11 6.1.4.1 • Source of Toxicity Criteria 6-11 6.1.4.2 Cal-EPA toxicity Criteria 6-11 6.1.4.3 Toxicity of Polychlorinated Dibenzodioxins and Dibenzofurans 6-11 6.1.4.4 Estimation of the Potential Hazard of Lead 6-12 6.1.5 Risk Characterization 6-12 6.1.6 Results 6-14 6.1.6.1 IRP Site 4—Perimeter Road 6-14 6.1.6.2 !RP Site 5 —Clean Fill Disposal Area 6-22 6.1.6.3 IRP Site 6—Explosives Burning Ground 6-23 6.1.7 Uncertainty Analyses 6-24 6.1.7.1 Data Evaluation 6-25 6.1.7.2 Exposure Assessment 6-26 6.1.7.3 Toxicity Assessment 6-29 6.2 Ecological Screening Risk Assessment 6-30 6.2.1 Problem Formulation 6-30 6.2.1.1 Ecological Habitats at WPNSTA, Seal Beach 6-30 6.2.1.2 Ecological Receptors 6-31 6.2.1.3 Species of Special Status 6-32 Draft RSE Report, IRP Sites 4, 5,and 6, WPNSTA, Seal Beach, CA page vii 6/16/2000 621 pm ern n:V1ivyeActo151Yst Or661pre$.c*,onwxtVratr-dot-0.00c CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 6.2.1.4 Chemicals of Potential Ecological Concern 6-32 6.2.1.5 Exposure Pathways and Conceptual Site Model 6-32 6.2.1.6 IRP Site 4—Perimeter Road 6-33 6.2.1.7 1RP Site 5 — Clean Fill Disposal Area 6-34 6.2.1.8 IRP Site 6—Explosives Burning Ground 6-34 6.2.2 Exposure Assessment 6-35 6.2.2.1 Soil and Groundwater Exposure-Point Concentrations 6-35 6.2.2.2 COPEC Concentrations in Biota 6-35 6.2.2.3 Estimated Chemical Intakes 6-35 6.2.3 Biological Effects Assessment 6-36 6.2.3.1 Toxicity Reference Values for Mammals and Birds 6-36 6.2.3.2 Soil and Sediment Screening Benchmark Values 6-37 6.2.3.3 Surface-Water Screening Benchmark Values 6-37 6.2.4 Characterization of Ecological Hazards 6-38 6.2.4.1 Potential Hazard to Receptors at IRP Site 4 6-39 6.2.4.2 Potential Hazard to Receptors at IRP Site 5 6-43 6.2.4.3 Potential Hazard to Receptors at IRP Site 6 6-44 6.2.5 Uncertainty Analysis 6-46 7 FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS 7.1 Perimeter Road —IRP Site 4 7-1 7.1.1 Findings, Conclusions, and Recommendations for AOPC 1A—IRP Site 4 7-1 7.1.1.1 Summary of Findings for Soils 7-2 7.1.1.2 Summary of Findings for Groundwater 7-2 7.1.1.3 Conclusions and Recommendations 7-3 7.1.2 Findings, Conclusions, and Recommendations for AOPC 2A—IRP Site 4 7-4 7.1.2.1 Summary of Findings for Soil 7-4 7.1.2.2 Summary of Findings for Groundwater 7-5 7.1.2.3 Conclusions and Recommendations 7-6 7.1.3 Findings, Conclusions, and Recommendations for AOPC 1R —IRP Site 4 7-7 page viii Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA N16r2000 6.21 pm tm n vlevytouao151vie prefltpresearonue:tvrstmoc-o o« CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Section Page 7.1.3.1 Summary of Findings 7-7 7.1.3.2 Conclusions and Recommendations 7-8 7.1.4 Findings, Conclusions, and Recommendations for AOPC 2R—IRP Site 4 7-9 7.1.4.1 Summary of Findings 7-9 7.1.4.2 Conclusions and Recommendations 7-10 7.1.5 Findings, Conclusions, and Recommendations for AOPC 3R—IRP Site 4 7-10 7.1.5.1 Summary of Findings 7-10 7.1.5.2 Conclusions and Recommendations 7-11 7.1.6 Findings, Conclusions, and Recommendations for AOPC 4R—IRP Site 4 7-11 7.1.6.1 Summary of Findings 7-11 7.1.6.2 Conclusions and Recommendations 7-12 7.1.7 Findings, Conclusions, and Recommendations for AOPC 5R—IRP Site 4 7-13 7.1.7.1 Summary of Findings 7-13 7.1.7.2 Conclusions and Recommendations 7-14 7.1.8 Findings, Conclusions, and Recommendations for AOPC 6R—IRP Site 4 7-14 7.1.8.1 Summary of Findings 7-14 7.1.8.2 Conclusions and Recommendations 7-15 7.1.9 Findings, Conclusions, and Recommendations for AOPC 7R— IRP Site 4 7-15 7.1.9.1 Summary of Findings 7-15 7.1.9.2 Conclusions and Recommendations 7-16 7.1.10 Findings, Conclusions, and Recommendations for AOPC 8R—IRP Site 4 7-16 7.1.10.1 Summary of Findings 7-17 7.1.10.2 Conclusions and Recommendations 7-18 7.1.11 Findings, Conclusions, and Recommendations for AOPC 9R—IRP Site 4 7-18 7.1.11.1 Summary of Findings 7-18 7.1.11.2 Conclusions and Recommendations 7-19 Draft RSE Report, IRP Sites 4, 5,and 6, WPNSTA, Seal Beach, CA page ix 6116/2000 6.21 pm tm n:Wvytbtct3151 Vse OnMtpniwctwnVextvrstr.tocd.tloc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) L i Section Page 7.1.12 Findings, Conclusions, and Recommendations for AOPC lOR—IRP Site 4 7-19 7.1.12.1 Summary of Findings 7-19 7.1.12.2 Conclusions and Recommendations 7-20 7.2 Clean Fill Disposal Area—IRP Site 5 7-20 7.2.1 Findings, Conclusions, and Recommendations for Clean Fill Disposal Area—IRP Site 5 7-21 7.2.1.1 Summary of Findings for Soils 7-21 7.2.1.2 Summary of Findings for Groundwater 7-22 7.2.1.3 Conclusions and recommendations 7-24 7.2.2 Findings, Conclusions, and Recommendations for Sediments—IRP Site 5 7-25 7.2.2.1 Summary of Findings 7-25 7.2.2.2 Conclusions and Recommendations 7-26 7.3 Explosives Burning Ground—IRP Site 6 7-26 7.3.1 Findings, Conclusions, and Recommendations for AOPC 1N—IRP Site 6 7-26 7.3.1.1 Summary of Findings 7-27 7.3.1.2 Conclusions and Recommendations 7-28 7.3.2 Findings, Conclusions, and Recommendations for AOPC 1S—IRP Site 6 7-28 7.3.2.1 Summary of Findings 7-28 7.3.2.2 Conclusions and Recommendations 7-30 7.3.3 Findings, Conclusions, and Recommendations for AOPC 2—IRP Site 6 7-30 7.3.3.1 Summary of Findings 7-31 7.3.3.2 Conclusions and Recommendations 7-32 7.3.4 Findings, Conclusions, and Recommendations for Groundwater—IRP Site 6 7-32 7.3.4.1 Summary of Findings for Groundwater— IRP Site 6 7-32 7.3.4.2 Conclusions and Recommendations 7-34 8 REFERENCES page x Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/1612000 621 pm tm n:lnavylbkcto151 Moe d,ft respa,onuestvrsn4octi Poc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) VOLUME II TABLES Table Tables page ES-1 Summary of Estimated Human-Health and Ecological Risks for AOPCs of IRP Site 4 (in Executive Summary) ES-2 Summary of Estimated Human-Health and Ecological Risks for IRP Sites 5 and 6 (in Executive Summary) ES-3 Summary of Conclusions and Recommendations, IRP Site 4 (in Executive Summary) ES-4 Summary.of Conclusions and Recommendations, IRP Site 5 (in Executive Summary) -ES-5 Summary of Conclusions and Recommendations,IRP Site 6 (in Executive Summary) 3-1 Information on Municipal Wells Located Within a 4-Mile Radius, • Naval Weapons Station, Seal Beach 3-1 3-2 Information on Domestic, Commercial, and Community Wells Located Within a 4-Mile Radius,Naval Weapons Station, Seal Beach 3-3 3-3 Correlation of Aquifer Nomenclature, Seal Beach Area 3-4 3-4 Summary of Lithological and Hydrogeologic Features for Water-Bearing Intervals,Naval Weapons Station, Seal Beach 3-5 4-1 Summary of DQOs for IRP Site 4 (Perimeter Road) 4-1 4-2 Summary of DQOs for IRP Site 5 (Clean Fill Disposal Area) 4-3 4-3 Summary of DQOs for IRP Site 6 (Explosives Burning Ground) 4-5 4-4 Summary of Optimization for Sampling Design, IRP Sites 4, 5, and 6 4-7 4-5 Soil Sample Analyses at IRP Site 4, AOPC 1 A 4-9 4-6 Soil Sample Analyses at IRP Site 5 4-21 4-7 Soil Sample Analyses at IRP Site 6 4-23 4-8 Groundwater Sample Analyses at IRP Site 4, AOPC IA and AOPC 2A 4-27 Draft RSE Report, IRP Sites 4, 5,and 6,WPNSTA, Seal Beach, CA page xi 6116/2000 621 pm Im n:wvyiblao15tVie asma.sec+'onv*Mvrsv-ac-0.aa CLEAN II CTO-0151/0197 • Date: 06/22/00 TABLE OF CONTENTS (continued) b • Table Tables page 4-9 Groundwater Sample Analyses at 1RP Site 5 4-28 4-10 Groundwater Sample Analyses at 1RP Site 6 4-29 4-11 Analytical Methods for Soil and Groundwater 4-30 4-12 Soil Screening Criteria, IRP Sites 4, 5, and 6 4-31 4-13 Groundwater Screening Criteria, IRP Sites 4, 5, and 6 4-33 5-1 Geochemical Background for Metals in Soil 5-1 5-2 Summary of General Stratigraphy and Observations Made for AOPCs 1R through 10R, 1 A and 2A,IRP Site 4 5-2 5- -3 Physical Parameters of Soil Samples Collected from IRP Site 4 5-6 -5-4 Descriptive Classification of Soils Based on pH Concentrations 5-7 5-5 Analytical Results of Detected Analytes in Soil Samples Collected from IRP Site 4 5-8 5-6 Summary of Descriptive Statistics for Detected Analytes in Soil Samples Collected from IRP Site 4 5-50 5-7 Summary of the pH Ranges in Soil at all AOPCs, IRP Site 4 5-63 5-8 Summary of Reported TOC Ranges in Soils at all AOPCs, IRP Site 4 5-64 5-9 Analytical Results of Detected Analytes in Groundwater Samples Collected from IRP Site 4 5-65 5-10 Summary of Descriptive Statistics for Detected Analytes in Groundwater Samples Collected from IRP Site 4 5-68 5-11 Groundwater Classification Based on Total Dissolved Solids 5-71 5-12 Summary of Results for Select Groundwater Quality Parameters for Samples Collected from Temporary Monitoring Wells and Monitoring Wells at IRP Sites 4, 5, and 6 5-73 5-13 Water Hardness Classification 5-75 page xii Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach,CA 6'16/2000 621 pm trn nire vylDWo151 Vse arlilltpresoectpnYtXtWritr•tCC4.000 CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Table Tables page 5-14 Summary Results for PAHs in Soil at IRP Site 4 5-76 5-15 Summary Results for PCDDs/PCDFs in Soil at IRP Site 4 5-77 5-16 Summary Results for PCBs in Soil at IRP Site 4 5-78 5-17 Summary Results for Metals in Soil at IRP Site 4 5-79 5-18 Summary of Transport Analyses—IRP Site 4, AOPC 1A, Soil 5-81 5-19 Summary of Transport Analyses—IRP Site 4, AOPC 1A, Groundwater 5-82 5-20 Summary of Transport Analyses—IRP Site 4, AOPC 2A, Soil 5-83 5-21 Summary of Transport Analyses—IRP Site 4, AOPC 2A, Groundwater 5-84 5-22 Summary of Transport Analyses—IRP Site 4, AOPC 1R 5-85 5-23 Summary of Transport Analyses—IRP Site 4, AOPC 2R 5-86 5-24 Summary of Transport Analyses—IRP Site 4, AOPC 3R 5-87 5-25 Summary of Transport Analyses—IRP Site 4, AOPC 4R 5-88 5-26 Summary of Transport Analyses—IRP Site 4, AOPC 5R 5-89 5-27 Summary of Transport Analyses—IRP Site 4, AOPC 6R 5-90 5-28 Summary of Transport Analyses—IRP Site 4, AOPC 7R 5-91 5-29 Summary of Transport Analyses—IRP Site 4, AOPC 8R 5-92 5-30 Summary of Transport Analyses—IRP Site 4, AOPC 9R 5-93 5-31 Summary of Transport Analyses—IRP Site 4, AOPC 1 OR 5-94 5-32 Physical Parameters of Soil Samples Collected from IRP Site 5 5-95 5-33 Analytical Results of Detected Analytes in Soil Samples Collected from IRP Site 5 5-96 5-34 Analytical Results of Detected Analytes in Sediment Samples Collected from IRP Site 5 5-102 Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page xiii 6/16/2000621 pm tmn:WvylDWot51Vise orantpresecuonue,evrstr•tocd.00c CLEAN II CTO-0151/0197 Date: 06/22i00 TABLE OF CONTENTS (continued) a Table Tables page 5-35 Summary of Descriptive Statistics for Detected Analytes in Soil Samples Collected from IRP Site 5 5-105 5-36 Summary of Descriptive Statistics for Detected Analytes in Sediment Samples Collected from IRP Site 5 5-107 5-37 Analytical Results of Detected Analytes in Groundwater Samples Collected from IRP Site 5 5-109 5-38 Summary of Descriptive Statistics for Detected Analytes in Groundwater Samples Collected from IRP Site 5 5-112 5-39 Summary of Transport Analyses— IRP Site 5, Soil 5-114 5-40 Summary of Transport Analyses— IRP Site 5, Sediment 5-115 5-41 Summary of Transport Analyses — IRP Site 5, Groundwater 5-116 5-42 Physical Parameters of Soil Samples Collected from IRP Site 6 5-117 5-43 Analytical Results of Detected Analytes in Soil Samples Collected from IRP Site 6 5-118 5-44 Summary of Descriptive Statistics for Detected Analytes in Soil Samples Collected from IRP Site 6 5-140 5-45 Analytical Results of Detected Analytes in Groundwater Samples Collected from IRP Site 6 5-144 5-46 Summary of Descriptive Statistics for Detected Analytes in Groundwater Samples Collected from IRP Site 6 5-146 5-47 Summary of Transport Analyses— 1RP Site 6, AOPC 1N 5-148 5-48 Summary of Transport Analyses — IRP Site 6, AOPC IS 5-149 5-49 Summary of Transport Analyses— IRP Site 6, AOPC 2 5-150 5-50 Summary of Transport Analyses—IRP Site 6, Groundwater 5-151 6-1 Values Assigned to Dose Equation Parameters 6-1 6-2 Dibenzo-p-dioxins and Furans Toxicity Equivalency Factors 6-3 page xiv Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Se& Beach, CA 6/16/2000 621 pm tm n Wvylb\ctol51y Orett4re>tecvonvex1 Tsu-locc ex CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Table Tables page 6-3 Cancer Risk Summary for IRP Sites 4, 5, and 6 6-4 6-4 Summary of Cancer Risk and Chronic Hazard Index,Residential Scenario, IRP Site 4 6-5 6-5 Summary of Cancer Risk and Chronic Hazard Index Drivers for Soil, Residential Scenario, IRP Site 4 6-8 6-6 Summary of Cancer Risk and Chronic Hazard Index for Navy Security Guard and U.S. FWS Staff, IRP Site 4 6-9 6-7 Summary of Cancer Risk and Chronic Hazard Index, IRP Site 5 6-10 6-8 Summary of Cancer Risk and Chronic Hazard Index, IRP Site 6, AOPC 1N 6-11 6-9 Summary of Cancer Risk and Chronic Hazard Index, IRP Site 6, AOPC 1S 6-12 6-10 Summary of Cancer Risk and Chronic Hazard Index, IRP Site 6, AOPC 2 6-13 6-11 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 4, AOPC 1A, Soil 6-14 6-12 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 4, AOPC 1 A, Groundwater 6-15 6-13 Summary of Hazard Quotients, for Values Greater Than 1, ERP Site 4, AOPC 2A, Soil 6-16 6-14 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 4, AOPC 2A, Groundwater 6-17 6-15 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 5, Soil 6-18 6-16 Summary of Hazard Quotients, for Values Greater Than 1,IRP Site 5, Sediment 6-19 6-17 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 5, Groundwater 6-20 6-18 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 6, AOPC 1N, Soil 6-21 Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page xv 6/16/2000 621 pm Pn n:wvylbwo1Slfe draft praeevonueavmraoatlDoc CLEAN II CTCV-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Table Tables page 6-19 Summary of Hazard Quotients, for Values Greater Than 1,IRP Site 6, AOPC 1S, Soil 6-22 6-20 Summary of Hazard Quotients, for Values Greater Than 1, IRP Site 6, AOPC 2, Soil 6-23 6-21 Summary of Hazard Quotients, for Values Greater Than 1,1RP Site 6, Groundwater 6-24 7-1 Summary of Conclusions and Recommendations, IRP Site 4 7-1 7-2 Summary of Conclusions and Recommendations, IRP Site 5 7-3 7-3 Summary of Conclusions and Recommendations, IRP Site 6 7-4 VOLUME II FIGURES Figure ES-1 Site Location Map (in Executive Summary) ES-2 Surveyed Sampling Locations in the Southern Portion of IRP Site 4 (in Executive Summary) ES-3 Surveyed Sampling Locations in the Northern Portion of IRP Site 4 (in Executive Summary) ES-4 Surveyed Sampling Locations in the AOPCs 1A and 2A Accumulation Areas, IRP Site 4 (in Executive Summary) ES-5 Base Map—IRP Site 5 (in Executive Summary) ES-6 Base Map—IRP Site 6 (in Executive Summary) 1-1 Regional Map 1-2 Site Location Map 3-1 Surface Features page xvi Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/162000 6.21 pm bn n:Vyvylo1eto1 S1 Vse prlIMpres.yonYextl f W-rot4Aoe CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Figure 3-2 General Site Topography 3-3 General Geology of WPNSTA Seal Beach and Geologic Cross Section Location 3-4 Wells Within a 1.5 Mile Radius of Naval Weapons Station 3-5 Idealized Hydrogeologic Section A-A' Through Facility 3-6 Basewide Groundwater Flow Patterns in Shallow (50 Feet or Less bgs) Water-Bearing Zone 3-7 Alamitos Barrier Reclaimed Water Project Vicinity Map 3-8 Soil Distribution Map 4-1 Decision Tree for AOPCs at IRP Site 4 4-2 Decision Tree for IRP Site 5 4-3 Decision Tree for AOPCs at IRP Site 6 4-4 Surveyed Sampling Locations in the Southern Portion of IRP Site 4 4-5 Surveyed Sampling Locations in the Northern Portion of IRP Site 4 4-6 Surveyed Sampling Locations in the AOPCs lA and 2A Accumulation Areas, IRP Site 4 4-7 Base Map —IRP Site 5 4-8 Base Map — IRP Site 6 4-9 Stilling Well Location Map 4-10 Revised Sampling Grid and Soil/Sediment Sampling Locations at IRP Site 5 5-1 Conceptual Site Model for IRP Site 4, AOPCs 1R and 2R and AOPCs IA and 2A 5-2 Conceptual Site Model for IRP Site 4, AOPCs 3R through l OR 5-3 Groundwater Sample Results, Water Quality Parameters, AOPC 1 A—IRP Site 4 5-4 Groundwater Sample Results— Water Quality Parameters, AOPC 2A— IRP Site 4 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page xvii 6n8J2D00 621 pm trn n:tnevyttActoiSivse er3Mpewcuonuexnmsvloc4.0oc CLEAN II CT 0-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Figure 5-5 Soil Sample Results— Organics, AOPCs 1 A and IR — IRP Site 4 5-6 Soil Sample Results—Metals, AOPCs 1 A and IR—IRP Site 4 5-7 Soil Sample Results— Organics, AOPCs 2A and 2R— IRP Site 4 5-8 Soil Sample Results— Metals, AOPCs 2A and 2R—IRP Site 4 5-9 Soil Sample Results —Organics, AOPCs 3R to 6R— IRP Site 4 5-10 Soil Sample Results— Metals, AOPCs 3R to 6R—IRP Site 4 5-11 Soil Sample Results— Organics, AOPCs 7R to 10R— IRP Site 4 5-12 Soil Sample Results— Metals, AOPCs 7R to IOR — IRP Site 4 5-13 Groundwater Sample Results— Organics, AOPC IA — IRP Site 4 5-14 Groundwater Sample Results—Metals, AOPC IA — IRP Site 4 5-15 Groundwater Sample Results— Organics, AOPC 2A — IRP Site 4 5-16 Groundwater Sample Results—Metals, AOPC 2A— IRP Site 4 5-17 Geologic Map — IRP Site 5 5-18 Geologic Cross Section A-A', IRP Site 5 5-19 Geologic Cross Section B-B', IRP Site 5 5-20 Geologic Cross Section C-C', IRP Site 5 5-21 Geologic Cross Section D-D', IRP Site 5 5-22 Disposal Fill Thickness Contour Map, IRP Site 5 5-23 Groundwater Levels in Shallow Water-Bearing Interval in the Vicinity of IRP Site 5, December 1998 Monitoring Event 5-24 Conceptual Site Model for Clean Disposal Fill Area— IRP Site 5 5-25 Water Quality Parameters, IRP Site 5 page xviii Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16?000 6.21 pm tm n VuvyiDtctoi 51 vte driftpresecuonuextursrc-toc-d Ooc CLEAN II CTO-015110197 Date 06122'00 TABLE OF CONTENTS (continued) Figure 5-26 Soil Sample Results — Organics, IRP Site 5 5-27 Soil Sample Results — Metals, IRP Site 5 5-28 Sediment Sample Results— Metals, IRP Site 5 5-29 Groundwater Sample Results— Organics, IRP Site 5 5-30 Groundwater Sample Results— Metals, IRP Site 5 5-31 Vertical Magnetic Gradient Anomaly Map, IRP Site 6 5-32 Terrain Conductivity Anomaly Map, IRP Site 6 5-33 Geologic Map — IRP Site 6 5-34 Geologic Cross Section A-A', IRP Site 6 5-35 Geologic Cross Section B-B', IRP Site 6 5-36 Geologic Cross Section C-C', IRP Site 6 5-37 Geologic Cross Section D-D', IRP Site 6 5-38 Groundwater Levels in the Shallow Water-Bearing Interval in the Vicinity of IRP Site 6, 16 December 1998 (Noon) 5-39 Conceptual Site Model for AOPC IN, IRP Site 6 5-40 Conceptual Site Model for AOPC 1S, IRP Site 6 5-41 Water Quality Parameters, IRP Site 6 5-42 Soil Sample Results—Metals, IRP Site 6, AOPC 1N 5-43 Soil Sample Results— Organics, IRP Site 6, AOPC IS 5-44 Soil Sample Results— Metals, IRP Site 6, AOPC IS 5-45 Soil Sample Results — Metals, IRP Site 6, AOPC 2 5-46 Groundwater Sample Results— Organics, IRP Site 6 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page xix 6/167000621 prn t n n.vtavylb cto151vse Orafipesectonuextvrstr•loc-d ooc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) Figure 5-47 Groundwater Sample Results—Metals, IRP Site 6 6-1 Exposure Pathways for IRP Sites 4, 5, and 6 6-2 Total lifetime Cancer Risk of Soils at IRP Site 4, Residential Scenario 6-3 Total Lifetime Cancer Risk of Soils at IRP Site 4 by Pathway, Residential Scenario 6-4 Cancer Risk Drivers in Soil at IRP Site 4, AOPCs 2A and 2R to 5R, Residential Scenario 6-5 Cancer Risk Drivers in Soil at IRP Site 4, AOPCs 6R to 10R, Residential Scenario 6-6 Hazard Index of Soils at IRP Site 4, Residential Scenario 6-7 Hazard Index of Soils at IRP Site 4 by Pathway, Residential Scenario 6-8 Total Lifetime Cancer Risk from Exposure to Soil at IRP Site 4, Navy Security Guard and U.S. FWS Staff 6-9 Total Lifetime Cancer Risk at IRP Site 4 by Pathway, Navy Security Guard and U.S. FWS Staff Member 6-10 Cancer Risk Drivers in Soil at IRP Site 4 AOPCs 1R-10R, Navy Security Guard 6-11 Hazard Index of Soils at 1RP Site 4, Navy Security Guard and U.S. FWS Staff 6-12 Total Lifetime Cancer Risk at IRP Sites 5 and 6, U.S. FWS Staff Members 6-13 Total Lifetime Cancer Risk at 1RP Sites 5 and 6 by Pathway, U.S. FWS Staff Members 6-14 Hazard Index at IRP Sites 5 and 6, U.S. FWS Staff Members page xx Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16/2000621 pm tm n:lnavylin to 151 vile pr*Rhp.esectonvex1VtstT-tOC4.tloc CLEAN II CTO-015110197 Date 06%22100 TABLE OF CONTENTS (continued) APPENDICES VOLUME III Appendix A FIELD INVESTIGATION METHODS AND PROCEDURES B GEOPHYSICAL SURVEY REPORT C UXO SURVEY REPORT D RADIATION SURVEY REPORT E HEALTH AND SAFETY CLOSE-OUT REPORT F TRENCH LOGS, GEOLOGIC BOREHOLE LOGS, AND WELL CONSTRUCTION DETAILS G CONE PENETROMETER TEST DATA H GEOTECHNICAL LABORATORY RESULTS I TIDAL INFLUENCE SURVEY VOLUME IV Appendix J LABORATORY ANALYTICAL DATA VOLUME V Appendix K FIELD MEASUREMENTS L CALCULATION OF TOTAL 2,3,7,8-TCDD-EQUIVALENT CONCENTRATION M GEOCHEMICAL ASSESSMENT FOR SELECT METALS IN SOIL N SURVEYOR'S REPORT Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page xxi 6/16/2000 621 pm tin n Wvylblctot51Vx Orsflpiesett.onUenvrsu•toc-d Doc CLEAN II CTO-0151/0197 Date: 06/22/00 TABLE OF CONTENTS (continued) • VOLUME VI Appendix O 'DATA VALIDATION REPORTS (continues in Volume VII) VOLUME VII Appendix O DATA VALIDATION REPORTS (continued from Volume VI) VOLUME VIII Appendix P TRANSPORT MODELING Q HUMAN-HEALTH STREAMLINED RISK EVALUATION Appendix Text Part 1: Exposure-Point Concentrations Part 2: IRP Site 4 Risk Statistics Output Part 3: IRP Site 5 Risk Statistics Output Part 4: IRP Site 6 Risk Statistics Output (continues in Volume IX) VOLUME IX Appendix Q HUMAN-HEALTH STREAMLINED RISK EVALUATION (continued from Volume VIII) Part 5: IRP Site 4 Risk Characterization Results and Incremental Results Part 6: IRP Site 5 Risk Characterization Results and Incremental Results Part 7: IRP Site 6 Risk Characterization Results and Incremental Results R SCREENING ECOLOGICAL RISK ASSESSMENT S AERIAL PHOTOGRAPH REVIEW page xxii Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16/2C00 621 pm tm n wvy'o\ao 151 vse ar$ff4presecoonue.evnsir•tock ooc CLEAN II CTO-0151/0197 Date: 06/22/00 ACRONYMS/ABBREVIATIONS ABP Alamitos Barrier Project Ag/AgCI silver/silver chloride AOPC area of potential concern ASTM American Society for Testing and Materials AT123D analytical transient, one-,two-, and three-dimensional simulation AWQC Ambient Water Quality Criteria BCF bioconcentration factor BEIDMS Bechtel Environmental Integrated Data Management System bgs below ground surface B Bechtel National, Inc. CaCO3 calcium carbonate Cal-EPA California Environmental Protection Agency CAS Chemical Abstract Service CEC cation exchange capacity CERCLA Comprehensive Environmental Response, Compensation, and Liability Act (of 1980) CFR Code of Federal Regulations CLEAN Comprehensive Long-Term Environmental Action Navy COC chemical of concern COPC chemical of potential concern COPEC chemical of potential ecological concern COP WQO California Ocean Plan Water Quality Objectives CPT cone penetrometer test CSF cancer slope factor CTO Contract Task Order DAF dermal adherence factor DDD dichlorodiphenyldichloroethane DDE dichlorodiphenyldichloroethylene DDT dichlorodiphenyltrichloroethane DERP Defense Environmental Restoration Program DNT dinitrotoluene DO dissolved oxygen DoD United States Department of Defense DON United States Department of the Navy DQO data quality objective DTSC (Cal-EPA) Department of Toxic Substances Control DWR (California) Department of Water Resources Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seat Beach, CA page xxiii 6r16T2000 6.21 pm tm n:VnavytMeto151%m drarnpresecuonuextVrstr-toc-O.00c CLEAN II CTO-0151/0197 Date: 06/22/00 ACRONYMS/ABBREVIATIONS (continued) EGL Environmental Geotechnical Laboratory Eh electromotive force (electric potential) EM electromagnetic terrain conductivity EOD explosive ordnance demolition EPC exposure-point concentration ERA ecological risk assessment ERN Environmental Restoration Navy(Account) °F Fahrenheit, degrees FFSRA Federal Facility Site Remediation Agreement FSI Focused Site Inspection Fugro Fugro Geosciences, Inc. H4 hydrogen ion HEAST (U.S. EPA) Health Effects Assessment Summary Tables HERD Human Ecological Risk Division (Cal-EPA) HHRA human-health risk assessment HI hazard index HpCDD heptachlorodibenzo-p-dioxin HpCDF heptachlorodibenzofuran ) HQ hazard quotient HQm modified hazard quotient HxCDF hexachlorodibenzofuran IAS Initial Assessment Study IDW investigation-derived waste IRIS (U.S. EPA) Integrated Risk Information System IRP Installation Restoration Program Jacobs Jacobs Engineering Group, Inc. Kearney A.T. Kearney, Inc. Keith Keith International, Inc. kg kilogram kg/day kilograms per day Kow octanol-water partition coefficient LDC Laboratory Data Consultants LOAEL lowest-observed-adverse-effect level mg/cm2 milligrams per square centimeter mg/kg milligrams per kilogram mg/kg-day milligrams per kilogram per day page xxiv Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6y19,2000 12 05 pm lm 11:11Ckm0010VcrwitkYt�vy1D\C10151 Mite Orffl‘prsflcLOnUe[ivrst,10C.0 tlOC CLEAN II CTO-015110197 Date 06'22100 ACRONYMS/ABBREVIATIONS (continued) mg/L milligrams per liter m3/hr cubic meters per hour mm millimeter mole kg t moles of charge per kilograms of adsorbent MSL mean sea level MTBE methyl-tert-butyl ether mV millivolt µg/dL micrograms per deciliter µg/kg micrograms per kilogram µg/L micrograms per liter µm micrometers µmhos/cm micromhos per centimeter µR/hour microroentgens per hour NACIP Navy Assessment and Control of Installation Pollutants (Program) NASA National Aeronautics and Space Administration NCP National (Oil and Hazardous Substances Pollution) Contingency Plan NFESC Naval Facilities Engineering Service Center NOAEL no-observed-adverse-effect level NPL National Priorities List NTU nephelometric turbidity unit NWR National Wildlife Refuge OCDD octachlorodibenzo-p-dioxin OCDF octachlorodibenzofuran OCWD Orange County Water District OEW ordnance explosive waste OH- hydroxyl ion ORP oxidation-reduction potential OU operable unit PA Preliminary Assessment PAH polynuclear aromatic hydrocarbon PARCC precision, accuracy, representativeness, comparability, and completeness PCB polychlorinated biphenyl PCDD polychlorinated dibenzodioxin PCDF polychlorinated dibenzofuran pgg picograms per gram pH hydrogen-ion activity PM10 airborne particulate matter with an aerodynamic diameter of 10 micrometers or less POLB Port of Long Beach Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page xxv 6/19/2000 12.05 pm Im Ilsaos0010vwrwaikv>avy1b\\0o151 vse Orahlpresecuonueslvnsir.Ioc-a aoc CLEAN II CTO-0151/0197 Date: 06/22/00 ACRONYMS/ABBREVIATIONS (continued) PQL practical quantitation limit PRG preliminary remediation goal QAPP Quality Assurance Project Plan RBCA risk-based corrective action RCRA Resource Conservation and Recovery Act RDX cyclo-1,3,5-trimethylene-2,4,6-trinitramine redox reduction-oxidation RFA RCRA Facility Assessment RfD reference dose RI Remedial Investigation RME reasonable maximum exposure RSE Removal Site Evaluation RWQCB (Cal-EPA) Regional Water Quality Control Board SARA Superfund Amendments and Reauthorization Act (of 1986) SARWQCB (Cal-EPA) Regional Water Quality Control Board, Santa Ana Region SC specific conductance SI Site Inspection SOP standard operating procedure SRE streamlined risk evaluation SSVL soil screening value for leaching transport SVOC semivolatile organic compound SWDIV Southwest Division Naval Facilities Engineering Command SWMU solid waste management unit TAL Target Analyte List TCDD tetrachlorodibenzo-p-dioxin TCDF tetrachlorodibenzofuran TDS total dissolved solids TEF toxic equivalent factor TKN total Kjeldahl nitrogen TNT trinitrotoluene TOC total organic carbon TPHd total petroleum hydrocarbons as diesel TPHg total petroleum hydrocarbons as gasoline TRPH total recoverable petroleum hydrocarbons TRV toxicity reference value UCL upper confidence limit ULBV upper limit background value ) USCS Unified Soil Classification System page xxvi Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/1612000 621 pm(re n:wvyltActo151 Vse onnspresecsonuexnmtr-ux-0 Ooc CLEAN II CTO-015110197 Date 06'2200 ACRONYMS/ABBREVIATIONS (continued) U.S. EPA United States Environmental Protection Agency U.S. FWS United States Fish and Wildlife Service UXO unexploded ordnance VLEACH vadose zone leaching VMG vertical magnetic gradient VOC volatile organic compound WDC Water Development Corporation WPNSTA Naval Weapons Station Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page xxvii 6/162000 621 pm tm n wvylbActo15l Vse Orst prosect onuextvrxv.toc-d doc CLEAN II CTO-0151/0197 Date: 06/22/00 ACRONYMS/ABBREVIATIONS (continued) This page left blank intentionally page xxviii Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16/2000 6.21 pm tm nAYyvy1otcto151 Y1e Or.ft,prss.c1,on4a tyr str-toc-d Doc CLEAN II CTO-0151/0197 Date: 0672'00 Section 7 FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS A summary of findings, conclusions, and recommendations for IRP Sites 4, 5, and 6 are presented in this section for each site/AOPC. The conclusions and recommendations are based on the findings of the field activities conducted at the sites, the soil and groundwater analytical results discussed in Section 5, the geochemical analysis of metals and fate and transport evaluations of COPCs discussed in Section 5, and the risk assessment results presented in Section 6 of this report. The RSE objectives for IRP Sites 4, 5, and 6 have been satisfied as a result of the various investigations and assessment conducted. The DQOs developed in the final RSE Work Plan (BNI 1998a) set forth specific guidance for developing recommendations for the various sites./AOPCs: the sites/AOPCs would be recommended for no further action, removal action, or further evaluation. The primary decision for IRP Sites 4, 5, and 6 is: "if the COPCs in soil or groundwater pose a risk to human health or the environment, then further evaluation or removal action will be undertaken." Conclusions and recommendations made for IRP Sites 4, 5, and 6 soil and groundwater consist of risk-based decisions, in accordance with the final RSE Work Plan (BNI 1998a). To determine if the COPCs at a site or AOPC pose a risk to human health and/or the environment (i.e., to answer the primary DQO question), the final RSE Work Plan (BNI 1998a) established human- health and ecological decision rules for 1RP Sites 4, 5, and 6. These decision rules are summarized in Section 4 of this report. The HHRA consisted of an SRE for baseline risk assessments associated with RSE. The decision rule for the risk decision is based on the exposure setting that produces the highest level of estimated risk for the site/AOPC. The screening ERA consisted of a comparison of the exposure estimates calculated using measured COPC concentrations in soil and groundwater to toxicological benchmarks. Findings for soil and groundwater used in formulating conclusions and developing recommendations are discussed for each site and/or AOPC and are summarized in Tables 7-1 through 7-3. Conclusions and recommendations are then presented for each site and/or AOPC. These conclusions and recommendations are also summarized in Tables 7-1 through 7-3. 7.1 PERIMETER ROAD — IRP SITE 4 This section presents, by AOPC, a summary of the findings, conclusions, and the recommendations for IRP Site 4. 7.1.1 Findings, Conclusions, and Recommendations for AOPC 1A — IRP Site 4 This section presents a summary of the findings for soil and groundwater, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 1A. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-1 6'162000 4 07 pm in1nMecoon_7uer1uec07. .Ooc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations 7.1.1.1 SUMMARY OF FINDINGS FOR SOILS Findings on the nature and extent of COPCs reported in soil are as follows. • Two PAHs,benzo(a)pyrene and benzo(b)fluoranthene, were reported at elevated concentrations,both at SB4-01A-03 at a depth of 0 to 1 foot bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 14 of the 44 samples collected in this accumulation area. Of these 14 samples, 9 were collected adjacent to the road at 0 to 1 foot bgs; 2 were collected away from the road at 0 to 1 foot bgs (SB4-01A-14,4.02 pg/g; SB4-01A-18,54.8 pg/g); and 3 were collected at 2 to 2.5 feet bgs (SB4- 01A-05, SB4-01A-15, and SB4-01A-16). A total 2,3,7,8-TCDD-equivalent concentration of 4.4 pg/g was reported at 2 to 2.5 feet bgs at SB4-01A-05; however,this concentration was lower than the concentration in the 0-to 1-foot bgs sample (22.2 pg/g). Total 2,3,7,8-TCDD-equivalent concentrations of 9.07 and 6.48 pg/g were reported at 2 to 2.5 feet bgs at SB4-OlA-15 and SB4-01A- 16,respectively; these concentrations were higher than the corresponding concentrations at 0 to 1 foot bgs. These soil samples were collected near the southeast corner of POLB Pond 4; this area may have undergone disturbance during the construction of the pond. • Aroclor 1254 and/or Aroclor 1260 were reported at elevated concentrations at four sampling locations,all at a depth of 0 to 1 foot bgs: SB4-01A-01, SB4- O l A-03, SB4-O l A-05,and SB4-01 A-15. • • Thirteen metals were reported in soils above the statistical background (including antimony,barium, chromium, cobalt, copper, lead,manganese, mercury, nickel, selenium, silver, vanadium, and zinc), and eight metals (antimony,barium, chromium, cobalt,manganese,nickel, silver, and zinc) were reported above the geochemical background. A vadose-zone leaching analysis, performed for COPCs in soil (including 14 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 17 metals), indicated that none of the COPCs would affect groundwater above the groundwater screening criteria. AOPC IA is a salt marsh habitat within the NWR; therefore, the potential risk to human health is not a concern and was not evaluated. Results of the ERA indicate that several soil COPCs showed HQ values greater than 1. However, after comparing these values to background conditions and to the range of TRVs, they did not appear ecologically significant. 7.1.1.2 SUMMARY OF FINDINGS FOR GROUNDWATER Findings on the geochemistry of groundwater at AOPC IA are as follows. • Groundwater collected from AOPC IA has reported TDS concentrations similar to that of seawater. Therefore,the shallow groundwater would not serve as a source for beneficial uses without prior treatment. • DO concentrations for groundwater ranged from 3.5 to 5.8 mg/L. page 7-2 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16r2000 4:07 pm tm 11600s0C 1 \rterwilkInen40001 S 1 Yse ore 6.0,00n 7Nfttlsl0074 00C CLEAN II CTO-015110197 Date: 0672100 Section 7 Findings, Conclusions, and Recommendations Findings on the nature and extent of COPCs reported in groundwater are as follows. • PAHs and PCBs were not reported above detection limits in groundwater samples collected from AOPC 1A. • The only PCDD/PCDF reported above detection limit was 1,2,3,4,6,7,8,9- OCDD,reported only in the groundwater sample collected from HP4-01A-01. • Six metals (antimony,barium, cadmium, manganese, selenium,and vanadium) and hexavalent chromium were reported at concentrations above detection limits. Antimony (three results out of three) and hexavalent chromium(one result out of three) were the only metals reported at concentrations above statistical background. None of the antimony concentrations were in excess of COP WQO. Hexavalent chromium was reported at a concentration of 9.5 µg/L in the groundwater sample collected from HP4-01A-03, at a depth of 7 to 10 feet bgs. This concentration for hexavalent chromium exceeds the COP WQO 6-month median concentration of 2 µg/L but is below the U.S. EPA AWQC for saltwater concentration of 50 p.g L. An evaluation to ascertain whether COPCs in groundwater at AOPC lA represent a potential future threat at a hypothetical point of exposure was conducted for two COPCs (total 2,3,7,8-TCDD-equivalent and hexavalent chromium) that exceeded groundwater screening criteria. Transport model simulations indicate that hexavalent chromium might affect groundwater above the groundwater screening criteria at the AOPC. However, the simulation indicates that groundwater at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC, is not affected. AOPC IA is a salt marsh habitat; therefore, potential risk to human health is not a concern and was not evaluated. Results of the ERA indicate that the potential effects to general marine life are low, based on comparing measured groundwater COPEC concentrations to water quality criteria. Two compounds exceed the water quality criteria: antimony (HQ of 7.0) and hexavalent chromium (HQ of 4.8). However, it is unlikely that marine life would be adversely affected at these levels. 7.1.1.3 CONCLUSIONS AND RECOMMENDATIONS The findings for soils at AOPC I yield the following conclusions. • The ERA suggests that none of the soil COPC concentrations are ecologically significant when compared to background conditions and the range of TRVs. • No COCs were identified in the soil of AOPC lA during this investigation. Based on the findings and conclusions for soil at AOPC 1A, soil is recommended for no further action. None of the soil COPCs are ecologically significant at the AOPC. The findings for the groundwater at AOPC IA yield the following conclusions. • Antimony and hexavalent chromium are COPCs in the groundwater of AOPC 1A. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-3 6162000 4.07 pm tm asOos0010worwIkVuvylD/cto151Yse d741ueChon_74ec11sec07.0 ooc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations • These two COPCs present a minimal risk to ecological receptors at the AOPC and at a hypothetical point of exposure; therefore,no further action appears warranted for the groundwater of AOPC 1A. The ERA estimates the risk posed to ecological receptors by antimony and hexavalent chromium to be minimal; therefore, no further action is recommended for the groundwater of AOPC 1A. 7.1.2 Findings, Conclusions, and Recommendations for AOPC 2A — IRP Site 4 This section presents a summary of the findings for soil and groundwater, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 2A. 7.1.2.1 SUMMARY OF FINDINGS FOR SOIL Findings on the nature and extent of COPCs reported in soil are as follows. • One PAH,benzo(a)pyrene,was reported at elevated concentrations at SB4- 02A-06 at a depth of 0 to 1 foot bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 16 of the 34 samples. Of these 16 samples, 9 were collected adjacent to the road at 0 to 1 foot bgs; 6 were collected away from the road at 0 to I foot bgs (SB4-02A-05, SB4-02A-09, SB4-02A-11, SB4-02A-13, SB4-02A-15, and SB4-02A-17). Most of these locations are near the northeastern end of the accumulation area: and 1 was collected at 2 to 2.5 feet bgs (SB4-02A-04,26.4 pg/g), where this concentration was lower than the 0-to 1-foot bgs sample by an order of magnitude. The northeastern end of the accumulation area where elevated total 2,3,7,8-TCDD-equivalent concentrations were reported may have been disturbed as this area appeared to have been used for agricultural purposes. These soil samples were collected at a distance of approximately 70 feet from the road. Based on the distance from the road to the soil samples with total 2,3,7,8-TCDD-equivalent concentrations below the residential PRG value, the width of the accumulation area is assumed to be 100 feet. • Aroclor 1254 and/or Aroclor 1260 were reported at elevated concentrations at four sampling locations, all at a depth of 0 to 1 foot bgs: SB4-02A-04, SB4- 02A-06, SB4-02A-07, and SB4-02A-17. The maximum concentrations for Aroclor 1254 (1 mg/kg) and Aroclor 1260 (0.2 mg/kg) were reported at SB4- 02A-04 and SB4-02A-17,respectively. • Metals reported at concentrations above statistical background consisted of antimony, arsenic,barium, chromium, copper, lead, mercury, and zinc. Of these metals,antimony, arsenic, barium, copper, and zinc were not reported at concentrations above the geochemical background. Arsenic (1 sample) and lead (12 samples) were reported at elevated concentrations. Elevated lead concentrations were reported at sampling locations SB4-02A-04, SB4-02A-06, page 7-4 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16x2000 4 07 pm Im Isclos0010vsyveigevlevylecto 51 vse pr*hglcUO 7Vfri.lC07-0 OOc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations SB4-02A-15, and SB4-02A-17, all at a depth of 0 to 1 foot bgs. A lead concentration of 309 mg/kg was reported at 2 to 2.5 feet bgs at sampling location SB4-02A-10 adjacent to the perimeter road. Vadose zone leaching and transport modeling for 30 analytes (12 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs and 15 metals) in soil at AOPC 2A indicates that none would affect groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 3.7 x 10-5, which is within the NCP's generally acceptable risk range of 104' to 104. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs/PCDFs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The estimated concentrations of lead in the blood of the resident child (15.8 to 35.7 p.g/dL at 50th to 99th percentiles, respectively) and the adult (10 to 13.1 µg c1L at 95'h to 99th percentiles, respectively) exceed the lead concentration of concern of 10 indicating the potential adverse health effects from exposure to lead at AOPC 2A. However, the residential scenario assumed for the AOPC is highly improbable. AOPC 2A is a combination of salt marsh habitat and grassland habitat. The ERA indicates that for lead the low-HQ value exceeded 1 for the robin (HQ of 230). However, the high-HQ value did not exceed 1 for robin exposure to lead, indicating that the lead concentrations may not be ecologically significant. The ERA also indicates that the total 2,3,7,8-TCDD-equivalent showed HQ values only slightly exceeding unity for several different indicator species; therefore, total 2,3,7,8-TCDD-equivalent is considered to be of minor ecological significance. 7.1.2.2 SUMMARY OF FINDINGS FOR GROUNDWATER Findings on the geochemistry of groundwater at AOPC 2A are as follows. • Groundwater collected from AOPC 2A has reported TDS concentrations similar to seawater. Therefore,the shallow groundwater would not serve as a source for beneficial uses without prior treatment. • DO concentrations for groundwater ranged from 3.0 to 4.0 mgt. Findings on the nature of COPCs reported in groundwater are as follows. • PAHs and PCBs were not reported above detection limits in the groundwater samples collected from AOPC 2A. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-5 6162000 4 07 pen tm‘ssooc0010 norwikwvyIo0o151 Yse orefl4oct.o.+_71ieruec07-C Ooc CLEAN it CTO-015110197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations • PCDDs/PCDFs were reported at concentrations above detection limits in all three groundwater samples. • Eight metals (antimony, arsenic,barium, cadmium, manganese, selenium, vanadium,and zinc)and hexavalent chromium were reported at concentrations above detection limits. Antimony(three results out of three), arsenic (one result out of three), and hexavalent chromium(one result out of three) were the only metals reported at concentrations above statistical background values. None of the antimony concentrations were in excess of COP WQO. Arsenic was reported at a concentration of 36 µg/L in the groundwater sample collected from HP4-02A-01,at a depth of 9 to 12 feet bgs. This concentration for arsenic exceeds the COP WQO 6-month median concentration of 8 µg2 but is equal to the U.S. EPA AWQC for saltwater concentration of 36 µg/L. Hexavalent chromium was reported at a concentration of 2.41 µg/L in the groundwater sample collected from HP4-02A-03, at a depth of 10 to 13 feet bgs. This concentration for hexavalent chromium exceeds the COP WQO 6-month median concentration of 2 µg/L but is below the U.S. EPA AWQC for saltwater concentration of 50 µg/L. Groundwater transport model simulations for COPCs detected in groundwater at AOPC 2A indicate that total 2,3,7,8-TCDD-equivalent might continue to affect the groundwater at the AOPC for the next 50 years. Groundwater transport model simulations indicate that groundwater at a hypothetical point of discharge into the marine environment, located some 50 feet from the AOPC, is not affected by the COPCs in the groundwater at • the AOPC. Results of the ERA indicate that the potential effects to general marine life are low, based on comparing measured groundwater COPEC concentrations to water quality criteria. Three compounds slightly exceeded the water quality criteria: antimony (HQ of 5.3), arsenic (HQ of 4.5), and hexavalent chromium (HQ of 1.2). However, it is unlikely that marine life would be adversely affected at these levels. 7.1.2.3 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for soil at AOPC 2A, the following can be concluded. • The maximum total cancer risk for AOPC 2A under the residential scenario is 3.7 x 10.5 and the HI is 0.10. Blood lead concentrations for both the resident child and adult exceed the threshold value of 10 µg/dL, but are based on the highly improbable residential scenario assumption. • PCDDs/PCDFs in the soil are of minor ecological significance at AOPC 2A. • No COCs were identified in the soil of AOPC 2A during this investigation. Based on the findings and conclusions for soil at AOPC 2A, soil is recommended for no further action. The total cancer risk for soil is within the NCP's generally acceptable risk range of 10-6 to le under the residential scenario; the HI is less than l; and blood lead concentrations exceed 10 µg/dL, but are based on the highly improbable residential scenario assumption. The ERA has quantified the soil as having HQ values slightly page 7-6 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6016!20001.07 pm tm 111ioe50010YterwrtkVyvytWel)151vx errsuecopn 7Wrtuec07-0.aoc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations greater than 1 for several indicator species for PCDDs/PCDFs, but their ecological significance is minor; therefore, AOPC 2A soil is recommended for no further action. Based on the findings for groundwater at AOPC 2A, the following can be concluded. • Antimony, arsenic, and hexavalent chromium are the primary COPCs in groundwater at AOPC 2A. • These three COPCs present a minimal risk to ecological receptors at the AOPC and/or at the hypothetical point of discharge;therefore,no further action appears warranted for the groundwater of this AOPC. Based on these conclusions, no further action is recommended for the groundwater of AOPC 2A. 7.1.3 Findings, Conclusions, and Recommendations for AOPC 1R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 1R. 7.1.3.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • One PAH, dibenz(a,h)anthracene, was reported at elevated concentrations at SB4-01 R-05 at a depth of 0 to 1 foot bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 7 of the 21 samples, 6 of which were in 0-to 1-foot bgs samples, with a maximum concentration of 15.2 pg%g at SB4-01 R-07 at a depth of 0 to 1 foot bgs. A total 2.3,7,8-TCDD-equivalent concentration of 8.72 pg/g was reported at SB4-01 R-03 at a depth of 2 to 2.5 feet bgs; however, a concentration below the PRG value was reported in the 3.5-to 4-foot bgs sample. • Three PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.1 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, copper, lead,mercury, selenium, vanadium, zinc, and hexavalent chromium. Of these metals, antimony, chromium, copper, vanadium, and zinc were not reported at concentrations above the geochemical background. Elevated lead concentrations were reported in soil (6 samples at 0 to 1 foot bgs and 1 sample at 2 to 2.5 feet bgs), with a maximum concentration of 484 mg/kg reported at SB4-01 R-07 at 0 to 1 foot bgs. Transport model simulations, assuming a 50-year time period, for 33 analytes (12 PAH compounds, total 2,3,7,8-TCDD-equivalent, 3 PCBs, and 17 metals) indicate that anthracene and fluorene might affect the groundwater at the AOPC at concentrations Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-7 6,162000 4 07 pm tm k%soo40010riav etkwvy7onaolSirse ersrPsecaon_7Uextksec07.0 occ CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations above the groundwater screening criteria. Transport model simulations also indicate that fluorene may affect groundwater at a hypothetical point of discharge into the marine environment, located approximately 30 feet from the AOPC. However, the low ratio of predicted fluorene concentrations to groundwater screening criteria suggests a low potential threat to groundwater. Risk to the U.S. FWS staff member, who represents the group participating in the clapper rail predator study, the clapper rail recovery study, and the raptor monitoring study, were calculated. The U.S. FWS staff member was assumed to be exposed to soil at IRP Site 4 AOPC 1R, the portion of the road within the NWR. The total and incremental cancer risks for the U.S. FWS staff member, derived by use of Cal-EPA toxicity criteria, were estimated at 3.2 x 10-7 and 2.7 x 10-7, respectively. The excess lifetime cancer risk to the U.S. FWS staff member was estimated to be below the NCP's point of departure of le and risks below this level can be interpreted as unconditionally acceptable. Similarly, the total and incremental cancer risks for the Navy security guard patrolling the perimeter road (AOPC 1R through 1OR) were estimated at 9.2 x 10.6 and 3.5 x 10-6, respectively. The excess lifetime cancer risk to the Navy security guard patrolling the road was quantified by the HHRH to be within the NCP's generally acceptable risk range of le to 10—. Cancer risk is principally associated with arsenic. Inhalation of particulate matter generated by the vehicle was the dominant risk pathway. Although the risk to the Navy security guard patrolling the road is also applicable to the rest of the perimeter road (AOPCs 2R through 1OR), it will not be repeated under the risk conclusions for AOPCs 2R through 1OR at lRP Site 4, but should be considered in risk evaluations for these AOPCs. • The HI value for the U.S. FWS staff member exposed to soil at the AOPC IR and the Navy security guard patrolling the road are less than one, indicating that systemic toxicity is unlikely. The risk for exposure to lead in soil is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Exposure to lead was assessed under the industrial scenario. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both scenarios. 7.1.3.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC IR, the following can be concluded. • The maximum cancer risk to the U.S. FWS staff member is 3.2 x 10.7,and the HI is less than 1. Therefore,the maximum total cancer risk is unconditionally' acceptable under this scenario. • The maximum cancer risk to the Navy security guard patrolling the perimeter road (including AOPC IR)was estimated at 9.2 x 104', within the NCP's generally acceptable range of 10.0 to le. The HI is less than 1. • No COCs were identified in the soil of AOPC IR during this investigation. page 7-8 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16!2000 4 07 pm tm\1t0os0010Y, * lkYyvytb`C1o1511Re troftrecbc, TNtntfec07O COC CLEAN II CIO-0151/0197 Date: 0672/00 Section 7 Findings, Conclusions, and Recommendations Based on the findings and conclusions for soil at AOPC IR, soil is recommended for no further action. The total cancer risk for soil is below or within the NCP's target risk range and the HI is less than 1. 7.1.4 Findings, Conclusions, and Recommendations for AOPC 2R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 2R. 7.1.4.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Two PAHs, benzo(a)pyrene and benzo(b)fluoranthene,were reported at elevated concentrations at SB4-02R-01 and SB4-02R-02,respectively,both at a depth of 0 to 1 foot bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 7 of the 18 samples, all of which were in 0-to 1-foot bgs samples, with a maximum concentration of 8.61 pg/g at SB4-02R-01. • Two PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.1 mg/kg. • Lead was the only metal with concentrations reported above statistical background (9 of 18 samples). Four samples had elevated lead concentrations reported, all at 0 to 1 foot bgs, with a maximum concentration of 368 mg/kg reported at SB4-02R-08. Transport model simulations, assuming a 50-year time period, for 26 analytes (9 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 14 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.8 x 1e, which is within the NCP's generally acceptable risk range of le' to 104. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Se& Beach, CA page 7-9 6116/2000 A.07 pm tr1\sOos0010vwrwanclnavylbtao151rse pr*hlsecnon-n itxUsec07-0.tlo[ CLEAN H CTO-Ol51ro197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations The estimated concentrations of lead in the blood of the resident child (10.6 to 13.4 p.g/dL at 95th to 99th percentiles, respectively) slightly exceed the lead concentration of concern of 10 pg/dL, indicating the potential adverse health effects from exposure to lead at AOPC 2R. However, the residential scenario assumed for the AOPC is highly improbable. 7.1.4.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 2R,the following can be concluded. • The maximum cancer risk for AOPC 2R under the residential scenario is 2.8 X 10-6,and the HI is 0.10. Blood lead concentrations for the resident child exceed the threshold value of 10 tg/dL,but are based on the highly improbable residential scenario assumption. • No COCs were identified in the soil of AOPC 2R during this investigation. Based on the findings and conclusions for soil at AOPC 2R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range; the HI is less than 1; and blood lead concentrations slightly exceed 10 p.g/dL, but are based on the highly improbable residential scenario assumption. 7.1.5 Findings, Conclusions, and Recommendations for AOPC 3R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 3R. 7.1.5.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Phenanthrene was the only PAH reported at concentrations above detection limits. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 16 samples, at a concentration of 7.88 pg/g at SB4-03R-01 at a depth of 0 to 1 foot bgs. • Two PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.07 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony and lead. Of these metals, antimony was not reported at concentrations above the geochemical background. Transport model simulations, assuming a 50-year time period, for 18 analytes (phenanthrene, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 14 metals) indicate that none page 7-10 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 61162000 4.07 pm tm IuoosOO I Oworw Ikwevyiocao151rse O'efl Hecuon 7Wnlsec074.0oc CLEAN II CTO-0151 10197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.6 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.10, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 3R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 .tg/dL. 7.1.5.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 3R, the following can be concluded. • The maximum cancer risk for AOPC 3R is 2.6 x 10-6 and the HI is 0.10. • No COCs were identified in the soil of AOPC 3R during this investigation. Based on the findings and conclusions for soil at AOPC 3R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.1.6 Findings, Conclusions, and Recommendations for AOPC 4R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 4R. 7.1.6.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Four PAHs were reported at concentrations above detection limits in the soil samples. The PAH with the highest frequency of detection was phenanthrene. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 6 of the 17 samples, with a maximum concentration of 29.6 pg/g at SB4-04R-07 at a depth of 2 to 2.5 feet bgs. However, a concentration below the PRG value was reported in the 3.5-to 4-foot bgs Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-11 6/167000 4.07 pm tm 1t&Oos001 Owonnikwvyio/ao151 Vie OrienseCUon_7uer1 WC07.O Ooc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations sample. The other five concentrations above the PRG value in 0-to 1-foot bgs soil samples were reported at SB4-04R-03 through SB4-04R-07. • Two PCBs were reported at concentrations above detection limits in the soil • samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.06 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, copper, lead, thallium, and hexavalent chromium. Of these metals, antimony, chromium, copper,and thallium were not reported at • concentrations above the geochemical background. A maximum lead concentration of 206 mg/kg was reported at SB4-04R-04 at 0 to 1 foot bgs. Transport model simulations, assuming a 50-year time period, for 23 analytes (4 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 14 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 9.8 X 10�, which is within the NCP's generally acceptable risk range of le to 104. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with PCDDs. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.091, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 4R is considered negligible based on the results of the Cal- EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. 7.1.6.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 4R, the following can be concluded. • The maximum total cancer risk for AOPC 4R is 9.8 x 10-6 and the HI is 0.091. • No COCs were identified in the soil of AOPC 4R during this investigation. Based on the findings and conclusions for soil at AOPC 4R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. page 7-12 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16,2000 4:07 pen trn ltsoos0010norweikvyvytDlaol Stvse cbon 7twt1wc07-0.Ooc CLEAN II CTO-0151/0197 Date. 0622100 Section 7 Findings, Conclusions, and Recommendations 7.1.7 Findings, Conclusions, and Recommendations for AOPC 5R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 5R. 7.1.7.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Nine PAHs were reported at concentrations above detection limits in the soil samples. The PAH with the highest frequency of detection was phenanthrene. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 16 samples, at a concentration of 4.17 pg/g at SB4-05R-08 at a depth of 0 to 1 foot bgs. • Aroclor 1260 was the only PCB reported above detection limits and in only one sample, at a concentration of 0.2 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, cobalt, lead,mercury,thallium, and hexavalent chromium. Of these metals, antimony and thallium were not reported at concentrations above the geochemical background. Transport model simulations, assuming a 50-year time period, for 25 analytes (8 PAH compounds, total 2,3,7,8-TCDD-equivalent, Aroclor 1260, and 15 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 1.9 x 10-6, which is within the NCP's generally acceptable risk range of 10-6 to 10—. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with Aroclor 1260. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.21, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 5R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-13 b162000 4.07 pm im tvsoos.0010worwsitwvyiotrso151rse orMrearoon_7%enwc07-0.00c CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations r 1 7.1.7.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 5R, the following can be concluded. • The maximum cancer risk for AOPC SR is 1.9 x 104,and the HI is 0.21. • No COCs were identified in the soil of AOPC 5R during this investigation. Based on the findings and conclusions for soil at AOPC 5R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.1.8 Findings, Conclusions, and Recommendations for AOPC 6R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 6R. 7.1.8.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • One PAH,benzo(a)pyrene, was reported at an elevated concentration at SB4- 06R-08, at a depth of 2 to 2.5 feet bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 6 of the 19 samples, 5 of which were in 0- to 1-foot bgs samples, with a maximum concentration of 43.7 pg/g at SB4-06R-06 at a depth of 0 to 1 foot bgs. A total 2,3,7,8-TCDD-equivalent concentration of 23.4 pgig • was reported at SB4-06R-08 at a depth of 2 to 2.5 feet bgs; however, a concentration below the PRG value was reported in the 3.5-to 4-foot bgs sample. • Two PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.06 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, arsenic,cobalt, and lead. Of these metals, antimony was not reported at concentrations above the geochemical background. Arsenic was reported at elevated concentrations: 36.7 and 123 mg/kg at sampling location SB4-06R-08 at depths of 2 to 2.5 and 3.5 to 4 feet bgs,respectively, and 38.1 mg/kg at sampling location SB4-06R-09 at a depth of 2 to 2.5 feet bgs. These two sampling stations arc located on the western portion of the AOPC,just east of Kitts Highway, and are approximately 100 feet apart. Transport model simulations, assuming a 50-year time period, for 29 analytes (12 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 15 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. page 7-14 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16/2000 407 pm tm\400s0010Y+arowk vlevlinct0151 Ytie CLOn 7renrec07.0 00C CLEAN II CTO-015110197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 4.3 x 10-5, which is within the NCP's generally acceptable risk range of 10� to 104. The incremental cancer risk was estimated to be 2.2 x 10'5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.52, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 6R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 .tg/dL. 7.1.8.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 6R, the following can be concluded. • The maximum cancer risk for AOPC 6R under the residential scenario is 4.3 x 10.5, and the HI is 0.52. • No COCs were identified in the soil of AOPC 6R during this investigation. Based on the findings and conclusions for soil at AOPC 6R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.1.9 Findings, Conclusions, and Recommendations for AOPC 7R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 7R. 7.1.9.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Four PAHs were reported at concentrations above detection limits in the soil samples. The PAH with the highest frequency of detection was phenanthrene with a maximum concentration of 0.1 mg/kg. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value only in 1 of the 18 samples, ata concentration of 8.11 pg/g at SB4-07R-08 at a depth of 0 to 1 foot bgs. • Aroclor 1260 was the only PCB reported above detection limits and in only one sample, at a concentration of 0.03 mg/kg. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-15 6162000 4.07 pm tm 11IOtri0010v10rvolkVlivylbulo151 Yye Orefluecuon_7uext\sec074 Ooc CLEAN II CTO-0151/0197 Date: 06122/00 Section 7 Findings, Conclusions, and Recommendations • . .Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver,thallium, and hexavalent chromium. Of these metals, antimony, chromium, silver, and thallium were not reported at concentrations above the geochemical background. Transport model simulations, assuming a 50-year time period, for 22 analytes (4 PAH compounds, total 2,3,7,8-TCDD-equivalent, Aroclor 1260, and 16 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.1 x 10-5, which is within the NCP's generally acceptable risk range of 10-6 to 10-4. The incremental cancer risk was estimated to be 2.0 x 10-5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.96, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult - receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 7R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. 7.1.9.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 7R, the following can be concluded. • The maximum cancer risk for AOPC 7R is 2.1 x 10-5,and the HI is 0.96. • No COCs were identified in the soil of AOPC 7R during this investigation. Based on the findings and conclusions for soil at AOPC 7R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range, and the HI is less than 1. 7.1.10 Findings, Conclusions, and Recommendations for AOPC 8R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 8R. page 7-16 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6'16/2000 4 07 pm on k%sOos0010YWrwllkWvylMcio151 vse oroMsocvon 7revhaecA7-0.00c CLEAN II C70-0151/0197 Date. 06/22/00 Section 7 Findings, Conclusions, and Recommendations 7.1.10.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Two PAHs,benz(a)anthracene and benzo(a)pyrene,were reported at elevated concentrations,both at SB4-08R-09 at a depth of 1.5 to 2.5 feet bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 5 of the 26 samples, 3 of which were in 0- to 1-foot bgs samples,with a maximum concentration of 15.5 pg/g at SB4-08R-07 at a depth of 0 to 1 foot bgs. Total 2,3,7,8-TCDD-equivalent concentrations of 6.17 and 5.32 pg/g were reported at SB4-08R-04 and SB4-08R-07,respectively, at a depth of 1.5 to 2.5 feet bgs; however,concentrations below the PRG value were reported in the 3.5-to 4-foot bgs samples. • Two PCBs were reported at concentrations above detection limits in the soil samples. Aroclor 1254 and 1260 were reported at maximum concentrations of 0.05 and 0.04 mg/kg,respectively. • Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver, and thallium. Of these metals, antimony, chromium, silver,and thallium were not reported at concentrations above the geochemical background. Transport model simulations, assuming a 50-year time period, for 31 analytes (12 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 16 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 2.7 x 10'5, which is within the NCP's generally acceptable risk range of 10-6 to 10-'. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with benzo(a)pyrene. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.24, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 8R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µgidL. Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page 7-17 6162000 5 47 pm tm noYyvytbncto151 Vse Oreuta,on_7uenuec07-0.00c CLEAN II • CTO-0151f0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations 7.1.10.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 8R, the following can be concluded. • The maximum cancer risk for AOPC 8R under the residential scenario is 2.7 x 10"5,and the HI is 0.24. • No COCs were identified in the soil of AOPC 8R during this investigation. Based on the findings and conclusions for soil at AOPC 8R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.1.11 Findings, Conclusions, and Recommendations for AOPC 9R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 9R. 7.1.11.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • One PAH,benzo(a)pyrene,was reported at an elevated concentration at SB4- 09R-02,at a depth of 0 to 1 foot bgs. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 12 of the 22 samples, 10 of which were in 0- to 1-foot bgs samples, with a maximum concentration of 26.0 pg!g at SB4-09R-06 at a depth of 0 to 1 foot bgs. Total 2,3,7,8-TCDD-equivalent concentrations of 4.99 and 6.95 pg/g were reported at SB4-09R-04 and SB4-09R-06,respectively, at a depth of 2 to 2.5 feet bgs; however,these concentrations were significantly below concentrations reported in the 0-to 1-foot bgs samples. • Three PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.09 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, chromium, cobalt, lead, silver,thallium, and hexavalent chromium. Of these metals, antimony, chromium, silver, and thallium were not reported at concentrations above the geochemical background. Transport model simulations, assuming a 50-year time period, for 29 analytes (9 PAH compounds, total 2,3,7,8-TCDD-equivalent, 3 PCBs, and 16 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 1.3 x 105, which is within the NCP's generally acceptable risk range of 10-6 to 104. The incremental cancer risk was estimated to be the same as the total lifetime cancer risk. page 7-18 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/162000 4 07 pm tm tlsoos0010vwr,.eN.wvyiDtuo151rse prshwcuon TNenwc07a ooc CLEAN II C70-0151/0197 Date: 0672/00 Section 7 Findings, Conclusions, and Recommendations The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with benzo(a)pyrene. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.39, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC 9R is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 p.g/dL. 7.1.11.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 9R, the following can be concluded. • The maximum cancer risk under the residential scenario for AOPC 9R is 1.3 x 10.5, and the HI is 0.39. • No COCs were identified in the soil of AOPC 9R during this investigation. Based on the findings and conclusions for soil at AOPC 9R, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.1.12 Findings, Conclusions, and Recommendations for AOPC 10R — IRP Site 4 This section presents a summary of the findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 10R. 7.1.12.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in soil are as follows. • Seven PAHs were reported at concentrations above detection limits in the soil samples. The PAH with the highest frequency of detection was phenanthrene. • Total 2,3,7,8-TCDD-equivalent concentrations were reported above the residential PRG value in 7 of the 18 samples, all of which were in 0- to 1-foot bgs samples, with a maximum concentration of 24.7 pg/g at SB4-10R-08. • Two PCBs were reported at concentrations above detection limits in the soil samples. The PCB with the highest frequency of detection was Aroclor 1254 with a maximum concentration of 0.04 mg/kg. • Metals reported at concentrations above statistical background consisted of antimony, barium, cadmium, chromium, cobalt, copper, lead, mercury, zinc, and Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-19 6/16:2000 4:07 pm tm 11i00$0010worwaikwvylb10o151Y7e orinWcb00_7Ut+t1{.007-o ooc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations - 1 hexavalent chromium. Of these metals,antimony,barium, chromium, copper, and zinc were not reported at concentrations above the geochemical background. Cadmium was the only metal with elevated concentrations reported, both in 0- to 1-foot bgs soil samples at SB-4-10R-01 (9 mg/kg)and SB4-10R-02 (37.4 mg/kg). Transport model simulations, assuming a 50-year time period, for 26 analytes (7 PAH compounds, total 2,3,7,8-TCDD-equivalent, 2 PCBs, and 16 metals) indicate that none of the COPCs in soil would affect the groundwater above the groundwater screening criteria. The total lifetime cancer risk to the hypothetical adult residential receptor was estimated at 3.5 x 10-5, which is within the NCP's generally acceptable risk range of 10-6 to 104. The incremental cancer risk was estimated to be 1.4 x 10-5, slightly lower than the total lifetime cancer risk. The cancer risk for the adult was estimated to be slightly higher than for the child. Cancer risk is principally associated with arsenic. The incidental soil ingestion pathway was the main contributor to residential risk. The HI associated with exposure to the COPC concentrations in soils and the COPC concentrations estimated in produce by a child receptor is below unity at 0.81, indicating that systemic toxicity is unlikely under the residential scenario evaluated by the HHRA. The noncancer risk estimates for the child receptor were higher than for the adult receptor. Incidental soil ingestion was the dominant pathway. The risk for lead at AOPC IOR is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 .tg/dL. 7.1.12.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 10R, the following can be concluded. • The maximum cancer risk under the residential scenario is estimated at 3.5 x 10.5,and the HI is 0.81. • No COCs were identified in the soil of AOPC l OR during this investigation. Based on the findings and conclusions for soil at AOPC 1OR, soil is recommended for no further action. The total cancer risk for soil is within the NCP's target risk range and the HI is less than 1. 7.2 CLEAN FILL DISPOSAL AREA - IRP SITE 5 This section presents a summary of the findings, conclusions, and recommendations for IRP Site 5. page 7-20 Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/16/2000 1 07 pm tm t4aos0010vanwmpltwvy40t00151 vst arsflwcb , 7Ytttli.007-0 cot CLEAN II CTO-0151/0197 Date: 0622/00 Section 7 Findings, Conclusions, and Recommendations 7.2.1 Findings, Conclusions, and Recommendations for Clean Fill Disposal Area — IRP Site 5 This section presents a summary of findings, including results of fate and transport evaluations and risk assessment for soil and groundwater, followed by conclusions and recommendations for IRP Site 5. 7.2.1.1 SUMMARY OF FINDINGS FOR SOILS The UXO survey indicated the presence of scattered live UXO, OEW, and scrap metals on the ground surface as well as at depth within the disposal fills. The UXO survey concluded that additional uninvestigated magnetic anomalies exist at IRP Site 5 and that UXO may still be present. Results of a radiological survey performed at IR? Site 5 indicated that exposure rates within the disposal area were well within the background range (areas surrounding the disposal fill area). A statistical comparison of the data indicated that the background population was the same as the IRP Site 5 population. Findings on the nature and extent of COPCs reported in soil are as follows. • Of the 11 VOCs reported above detection limits in IRP Site 5 soil samples, 10 VOCs were reported in one soil sample. These 10 VOCs consist of 1,2,4- trimethylbenzene; 1,3,5-trimethylbenzene; acetone; isopropylbenzene; meta-, para-xylene; methylene chloride; n-butylbenzcne; n-propylbenzene; p-isopropyltoluene; and sec-butylbenzene. The only other VOC reported above detection limits was a 2-butanone concentration of 8 µg/kg at SB5-00-07. • Three samples had SVOC concentrations reported above detection limits in IRP Site 5 soil samples. The SVOCs 4-methylphenol (0.5 mg/kg) and bis(2-ethylhexyl)phthalate (0.2 mg/kg) were reported at SB5-00-07 at a depth of 4.5 to 5 feet bgs. Bis(2-ethylhexyl)phthalate (0.1 mg/kg)and butyl benzyl phthalate (0.09 mg/kg)were reported above detection limits in soil samples collected at SB5-00-08 (4.5 to 5 feet bgs) and SB5-00-17 (0.5 to 1 foot bgs). • PAHs reported at elevated concentrations consist of benzo(a)pyrene, benzo(b)fluoranthene, and dibenz(a,h)anthracene,mostly in surface samples (0.5 to 1 foot bgs). The maximum concentrations in soil for these three PAI-Is were reported at SB5-00-16 at a depth of 0.5 to 1 foot bgs. The vertical extent of PAHs in soil is defined, with concentrations generally decreasing with depth. At the locations where PAHs were reported at elevated concentrations, lower concentrations were reported in soil samples collected at greater depths at the same locations,with the exception of a concentration of 0.6 mg/kg for dibenz(a,h)anthracene at SB5-00-07 at a depth of 4.5 to 5 feet bgs. • Aroclor 1254 and Aroclor 1260 were reported at concentrations above detection limits in soil, with maximum concentrations of 0.4 and 0.09 mg/kg,respectively. • Nitroaromatics and nitramines were not reported at concentrations above detection limits in any of the ten soil samples analyzed for explosives. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-21 6'16200C 4 07 pm tm 1ts0os0010vwrwlkvvvyi01a0151rut orsttutcu0n_nasal utc07c.00c CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations • Eight metals(antimony,arsenic, cadmium, chromium,cobalt,copper, lead,and zinc)and hexavalent chromium were reported above statistical background in soil samples collected at IRP Site 5. Of these metals, arsenic and chromium were not reported at concentrations above the geochemical background. The lateral and vertical extent of metals in soil at IRP Site 5 have generally been delineated to statistical background, a general decreasing trend, or to the fill boundary of the site. The lateral extent of COPCs in soil has been defined to the site boundary (fill material). Step-out sediment samples were collected and analyzed as a result of COPC concentrations in soil samples collected around the perimeter of the site in excess of screening criteria. The vertical extent of COPCs in soil is defined by groundwater, which is present at a depth of approximately 5 feet bgs beneath the site. Transport model simulations, assuming a 50-year time period, for 37 analytes (1 VOC, 2 SVOCs, 14 PAH compounds, 2 PCBs, 16 metals, and 2 inorganics analytes) reported in soil indicates that anthracene, fluorene, phenanthrene, copper, and ammonia in soil may affect the groundwater at the site above the groundwater screening criteria. Transport model simulations for groundwater indicate that none of the COPCs would affect • groundwater at a hypothetical point of discharge into the marine environment, located 250 feet from the site. The total and incremental excess lifetime cancer risk, derived by Cal-EPA carcinogenic toxicity criteria, for a U.S. FWS habitat restoration/maintenance supervisor and U.S. FWS tour guide exposed to soils and volatile compounds originating from the groundwater was estimated to be within the NCP's target risk range for health protectiveness (10 ' to 10-4) at 3.7 x 10-6 and 8.2 x le, respectively. The majority of the risk is associated with benzo(a)pyrene in soil. At IRP Site 5, benzo(a)pyrene was characterized with an 84 percent detection frequency and a lognormal distribution. The HI associated with exposure of the U.S. FWS habitat restoration/maintenance supervisor and U.S. FWS tour guide to soil at the site is less than 1.0, indicating that systemic toxicity is unlikely. The risk for exposure to lead by the U.S. FWS habitat restoration/maintenance supervisor was estimated based on exposures to an industrial worker. Under the industrial scenario the risk for exposure to lead in soil at IRP Site 5 is considered negligible based on the results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL. Results of the ERA indicate that the potential for ecological risk at this site appears quite low (HQ less than 1) based on comparisons to TRVs and stationwide background values. 7.2.1.2 SUMMARY OF FINDINGS FOR GROUNDWATER Findings on the geochemistry of groundwater at IRP Site 5 are as follows. • Groundwater is present at a depth of approximately 5 feet bgs beneath IRP Site 5. page 7-22 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/162000 4 07 pm tm a0os00101rerweIkWIVYtMCt0151 rse Or1h11eC9on 24111644.007.0 OCC CLEAN II CTO-0151/0197 Date: 0622/00 Section 7 Findings, Conclusions, and Recommendations • The shallow groundwater flow direction in the vicinity of IRP Site 5 is toward the east-northeast,with an overall gradient of 0.0001. • The anion and cation concentrations and the TDS data suggest that the shallow groundwater beneath IRP Site 5 is brackish to saline in nature. Therefore,the shallow groundwater would not serve as a source for beneficial uses without prior treatment. • Recorded DO concentrations for groundwater underlying IRP Site 5 ranged from 0.97 to 3.83 mg/L. • ORP values measured in groundwater indicate that the shallow groundwater environment beneath IRP Site 5 is characterized by moderately reducing conditions. Findings on the nature and extent of COPCs reported in groundwater are as follows. • Eighteen VOCs were reported above detection limits in IRP Site 5 groundwater samples. The most prevalent VOCs were 1,2-dichloroethane, isopropylbenzene, methyl-tert-butyl ether, sec-butylbenzene, and toluene. The largest number of VOCs reported above detection limits in any one sample was 10, at HP-05-02. VOCs were not reported at concentrations above the COP WQO or U.S. EPA AWQC for saltwater in any of the groundwater samples collected at 1RP Site 5. • Three SVOCs (except for PAHs and nitroaromatics!nitramines) were reported above detection limits in IRP Site 5 groundwater samples: diethyl phthalate. butyl benzyl phthalate, and di-n-butyl phthalate. SVOCs were not reported at concentrations above the COP WQO or U.S. EPA AWQC for saltwater in any of the groundwater samples collected at IRP Site 5. • Four PAHs, benzo(a)pyrene,benzo(g.h,i)perylene, fluoranthene, and pyrene, were reported above detection limits only in the groundwater sample collected at HP-05-02, at a depth of 12 to 15 feet bgs. The concentrations for benzo(a)pyrene (0.03 µg2),benzo(g.h,i)perylene (0.03 µg/L). and pyrene (0.05 pg'L) exceed the COP WQO for human health (30-day average) for total PAHs of 0.0088 µg/L. • Seven groundwater samples were analyzed for PCBs,none reported PCBs above the detection limits. • 1,3-Dinitrobenzene was reported above detection limit in one out of the seven groundwater samples analyzed for nitroaromatics and nitramines at IRP Site 5. The compound 1,3-dinitrobenzene was reported above the detection limit at a concentration of 0.6 µg2, in the groundwater sample collected from HP-05-04 at a depth of 18 to 21 feet bgs. No COP WQO or U.S. EPA AWQC for saltwater exists for 1,3-dinitrobenzene. • Ten metals (antimony, arsenic, barium, cadmium, cobalt, copper, manganese, selenium, vanadium, and zinc) and hexavalent chromium were reported above detection limits in groundwater samples collected from IRP Site 5. Of the ten metals, four metals (antimony, cobalt, manganese, zinc)and hexavalent chromium were reported at concentrations above statistical background. No Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-23 6/162000 4.07 pm tm\4.0040010v)0molavvvyib ao151vye orinuetvon_74e4gec07-0.0oc CLEAN II CM-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations - 1 COP WQO or U.S. EPA AWQC for saltwater exists for cobalt or manganese. None of the antimony concentrations were reported above the COP WQO for human health (30-day average). Zinc and hexavalent chromium concentrations were reported above the COP WQO(6-month median) concentrations; however, these concentrations were below the U.S. EPA AWQC for saltwater concentrations. An evaluation to ascertain whether COPCs in groundwater at IRP Site 5 represent a potential future threat at a hypothetical point of exposure was conducted for six COPCs that exceeded groundwater screening criteria. These COPCs are hexavalent chromium, cobalt, manganese (in area of brackish groundwater), zinc, ammonia, and nitrate. The transport model simulations indicate that hexavalent chromium, manganese, ammonia and nitrate could continue for 50 years to affect groundwater above the groundwater screening criteria at the site; however, only ammonia significantly exceeds the groundwater screening criteria. Furthermore, the simulations indicate that groundwater at a hypothetical point of discharge into the marine environment, located approximately 250 feet from the site, would not be affected. The effects of COPCs in groundwater on human health are included in the HHRA results for soil summarized in Section 7.2.1.1. Results of the ERA indicate that potential effects to general marine life are low, based on comparing measured groundwater COPEC • concentrations to water quality criteria. Six compounds exceeded the water quality criteria: antimony (HQ of 4.0), arsenic (HQ of 3.0), hexavalent chromium (HQ of 2.5), cobalt (HQ of 1.5), zinc (HQ of 2.5), and diethyl phthalate (HQ of l.2). However, it is unlikely that marine life would be adversely affected at these levels. 7.2.1.3 CONCLUSIONS AND RECOMMENDATIONS This section presents the conclusions and recommendations for soil and groundwater of IRP Site 5. Based on the findings for the soils of IRP Site 5, the following can be concluded. • Based on the numerous magnetic anomalies detected and only significant magnetic anomalies having been investigated during the UXO survey, the potential still exists for UXO to be present at the site. • The radiation survey indicates that collected readings are within the normal range for background, and no further action appears warranted at the site. • Benzo(a)pyrene is the primary contributor to the cancer risk at the site. However, the maximum estimated cancer risk for IRP Site 5 for both the U.S. FWS habitat restoration/maintenance and U.S. FWS tour guide scenarios is 3.7 x l0'6 and 8.2 x 106,respectively, and the human-health HI is less than I. • Results of the ERA indicate that the potential effects of reported analytes in soils on general marine life are estimated to be low. • Based on decision rules,no further action appears warranted for the reported COPCs in soil at IRP Site 5. page 7-24 Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA 6/16/2000 4 07 pm tm 51 VIM COC. 7Wrtvec07-0 OCC CLEAN II • C70-0151/0197 Date: 0&22100 Section 7 Findings, Conclusions, and Recommendations Based on the conclusions, no further action is recommended for the soils (fill and/or underlying Recent deposits) of IRP Site 5. The radiation survey indicates that the readings are within the normal background range; therefore, no further action is recommended with regard to evaluation of on-site radiological sources. However, the results of the UXO survey indicate that the potential still exists for UXO to be present in the disposal fill materials at the site. It is recommended that the potential for UXO to be present at the site be further evaluated, and any UXO identified by this evaluation be removed from the site. Conclusions regarding the groundwater of IRP Site 5 are as follows. • No risk-based COCs were identified in the groundwater of IRP Site 5. • The COPCs hexavalent chromium, manganese, ammonia, and nitrate might continue for the next 50 years to affect groundwater above the groundwater screening criteria at the site; however, only ammonia may significantly exceed the groundwater screening criteria. • Simulations indicate that none of the four COPCs listed above will affect the groundwater at a hypothetical point of discharge into the marine environment. • No further action appears warranted for the groundwater of IRP Site 5. Based on the conclusions, the groundwater of IRP Site 5 is recommended for no further action. 7.2.2 Findings, Conclusions, and Recommendations for Sediments — IRP Site 5 This section presents a summary of findings, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for sediment samples collected adjacent to IRP Site 5. 7.2.2.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs reported in the sediments are as follows. • No SVOCs, other than PAHs, were reported above detection limits in one sediment sample analyzed for SVOCs. • PAHs were reported at concentrations above detection limits in IRP Site 5 sediment samples. Benzo(a)pyrene and chrysene were reported above detection limits in more than 50 percent of the sediment samples. • Aroclor 1260 was reported at concentrations above detection limits in IRP Site 5 sediment samples, with a maximum concentration of 0.1 mg/kg. • Nitroaromatics and nitramines were not reported above detection limits in one sediment sample analyzed for explosives. • Nine metals (arsenic, cadmium, cobalt, copper, lead,nickel, selenium, vanadium, and zinc) and hexavalent chromium were reported above statistical Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-25 6/16/2000 4.07 pm im\WOt0010V10rr►Ikv1av b\C10151 Vion 7Vtxl\seC07-0 Pot CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations background in sediment samples collected around the perimeter of IRP Site 5. Of these metals, arsenic, copper,and zinc were not reported at concentrations above the geochemical background. An evaluation to ascertain whether COPCs in sediment at IRP Site 5 represent a potential future threat to groundwater was conducted for 29 analytes (11 PAH compounds, Aroclor 1260, 15 metals, and 2 other inorganic analytes). The transport model simulations, assuming a 50-year time period, indicate that ammonia may affect groundwater beneath the site above the groundwater screening criteria but would not affect groundwater at a hypothetical point of discharge into the marine environment, located 250 feet from the site. The area surrounding IRP Site 5 is a salt marsh. As a result, the potential risk to human health is not a concern; therefore, only potential risks to ecological receptors were evaluated. Sediment samples evaluated at IRP Site 5 were collected from the salt marsh area just beyond the site boundary. The findings of the ERA indicate that none of the COPECs are likely to represent a potential ecological risk to estuarine sediment invertebrates in the salt marsh habitat. 7.2.2.2 CONCLUSIONS AND RECOMMENDATIONS The conclusions regarding the sediments adjacent to IRP Site 5 are as follows. • The COPECs present in the sediments are estimated to pose little or no ecological risk to estuarine sediment invertebrates. ) • Fate and transport modeling indicates that ammonia may affect the groundwater beneath the sampling locations. However, fate and transport calculations indicate ammonia would not affect the groundwater at a hypothetical point of discharge into the marine environment. • No further action appears to be warranted for the sediments collected near IRP Site 5. Based on the conclusions, no further action is recommended for the sediments collected adjacent to IRP Site 5. 7.3 EXPLOSIVES BURNING GROUND — IRP SITE 6 This section presents a summary of the findings, conclusions, and recommendations for IRP Site 6. 7.3.1 Findings, Conclusions, and Recommendations for AOPC 1N — IRP Site 6 This section presents the findings for soil, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 1N. page 7-26 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6n6,20004:07 pmtm'tsoos001OwonNikwylowaot5 yseorenwc,or 7Nenrec07-Cooc CLEAN Ii CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations 7.3.1.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs in soils of AOPC IN are as follows. • Acetone and methylene chloride were the only VOCs reported at concentrations above detection limits. • No SVOCs, other than PAHs,which are discussed below,were reported above detection limits in the soil samples analyzed for SVOCs. • Thirteen of the 16 PAHs were reported above detection limits. The PAH with the highest frequency of detection was chrysene,with a maximum concentration of 0.38 mg/kg. • PCBs were not reported at concentrations above detection limits in any of the 36 soil samples analyzed for PCBs. • No nitroaromatics/nitramines were reported above detection limits in the 36 soil samples analyzed for SVOCs. • Reported ammonia values for soil in AOPC IN ranged from less than 0.2 to 1.2 mg/kg. • The concentration of nitrate in soil is less than stationwide statistical background value of 31.2 mg/kg. • Six metals (antimony, cobalt, copper, lead, silver, and thallium)and hexavalent chromium were reported at concentrations above statistical background. Of these metals, antimony, silver, and thallium were not reported at concentrations above the geochemical background. The lateral and vertical extents of COPCs in soil at AOPC IN have generally been delineated to nondetect or a general decreasing trend. The lateral and vertical extent of metals in soil at IRP Site 6, AOPC 1N have generally been delineated to background, a general decreasing trend, or to the AOPC boundary. An evaluation to ascertain whether COPCs in soil at AOPC 1N represent a potential future threat to groundwater was conducted for 33 analytes (1 VOC, 13 PAH compounds, 17 metals, and 2 other inorganic analytes). The model simulations for 50 years indicate that ammonia would not affect groundwater above the groundwater screening criteria at the AOPC or at a hypothetical point of discharge into the marine environment, located some 400 feet from the AOPC. The total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria, to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at IRP Site 6, AOPC IN, were estimated below the NCP's point of departure (10'). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 4.3 x 10-7 and 9.5 x 10-7, respectively. The HI associated with exposure of the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at IRP Site 6, AOPC IN is estimated at less Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page 7-27 6/16/2000 4 07 pm tm a1,001.0010worwiKvuvyIncto151 Vse&WI uect,or,_71enwc07- ooc CLEAN II CTO-015110197 Date: D 222100 Section 7 Findings, Conclusions, and Recommendations than 1. HI estimates below unity indicate that systemic toxicity is unlikely for both receptors. The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both receptors. Results of the ERA indicate that none of the calculated HQs for potential ecological receptors are greater than 1. Therefore, the potential ecological risk from COPECs at this AOPC is considered unlikely. 7.3.1.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC IN, the following can be concluded. • No COCs were identified in the soils at AOPC 1N. • The total cancer risk, using state parameters for the U.S. FWS habitat restoration/maintenance supervisor and U.S. FWS tour guide scenarios, is less than the point of departure (10-6)at 4.3 x 10.7 and 9.5 x 10.7,respectively, and • the HI for both scenarios is less than 1. • Results of the ERA indicate that HQs for ecological receptors are less than 1. • No further action for the soils of AOPC IN appears to be warranted. ) Based on the results of the HHRA indicating that the maximum cancer risk under the assumed scenarios is less than NCP's point of departure (10"6) and the HI is less than 1, and the ERA indicating low potential ecological risks, no further action is recommended for the soil of AOPC 1N. 7.3.2 Findings, Conclusions, and Recommendations for AOPC 1S — IRP Site 6 This section presents a summary of findings for soil, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for AOPC 1 S. 7.3.2.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs are as follows. • Nineteen samples had VOC concentrations reported above detection limits. Acetone and methylene chloride were reported with the highest frequency of detection. • Bis(2-ethylhexyl)phthalate and di-n-butyl phthalate were the only SVOCs reported above detection limits. • Four PAHs, benz(a)anthracene,benzo(a)pyrene,benzo(b)fluoranthene, and dibenz(a,h)anthracene were reported at elevated concentrations; the maximum page 7-28 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 616/7000 4 07 pm tm\1soos0010vwrvei►vuvyloxaot Siwe orsnwcuon llynwc074 ooc CLEAN II CTO-0151/0197 Date 06!22100 Section 7 Findings, Conclusions, and Recommendations concentrations for these PAHs were reported at SB6-05-23 at 0.5 to 1 foot bgs. Elevated PAH concentrations were also reported adjacent to SB6-05-23 at SB6- 05-21, SB6-05-22, and SB6-05-25, all at 0.5 to 1 foot bgs. • PCBs reported above detection limits consisted of Aroclor 1242,Aroclor 1254, and Aroclor 1260, with maximum concentrations reported at SB-05-23 at 0.5 to 1 foot bgs. • 2,4-Dinitrotoluene and n-nitrosodiphenylamine were reported at concentrations above detection limits only in the soil sample collected at SB6-05-19 at 0.5 to 1 foot bgs. • Ten metals(antimony, arsenic, chromium, cobalt, copper, lead, silver, selenium, thallium, and zinc) and hexavalent chromium were reported at concentrations above statistical background. Of these metals,antimony, chromium,copper, silver, thallium, and zinc were not reported at concentrations above the geochemical background. Arsenic (1 sample) and lead (I sample)were reported at elevated concentrations. • Reported ammonia values for soil samples collected from AOPC 1S ranged from less than 0.06 to 8.1 mg/kg, with the maximum concentration reported in the soil sample collected at SB6-07-03 at 0.5 to 1 foot bgs. The lateral and vertical extent of COPCs in soil at IRP Site 6, AOPC 1S have generally been delineated to nondetect or a general decreasing trend. The lateral and vertical extent of metals in soil have generally been delineated to background, a general decreasing trend, or to the site/AOPC boundary. Step-out soil samples were collected and analyzed as a result of COPC concentrations in soil samples in excess of screening criteria. An evaluation to ascertain whether COPCs in soil at IRP Site 6 AOPC 1S represent a potential future threat to groundwater was conducted for 42 analytes (2 VOCs, 4 SVOCs, 13 PAH compounds, 3 PCBs, 18 metals, and 2 other inorganic analytes). The model simulations, assuming a 50-year time period, indicate that anthracene, phenanthrene, and ammonia may affect groundwater above the groundwater screening criteria at the AOPC. However, at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC, only ammonia was indicated by the model simulations to affect groundwater above the screening criteria. The total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria, to the U.S. FWS habitat restoration/maintenance supervisor and to the U.S. FWS tour guide at AOPC 1S were estimated below the NCP's point of departure (10-6). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 2.3 x 10.7 and 5.0 x 10"7, respectively. The HI associated with exposure of the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at AOPC 1S is estimated at less than 1. HI estimates below unity indicate that systemic toxicity is unlikely for both receptors. Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-29 6/16/2000 4:07 pm tm tvaios00tOal secnon_7\extt ec07-C doc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both receptors. Results of the ERA indicate that the HQ values for the mouse and robin terrestrial receptors exceeded unity due to exposure to antimony and lead. Antimony showed HQ values exceeding unity for the mouse (HQ = 2.0) and robin (HQ = 2.5) receptors, and lead (HQ = 2.2) for the robin receptor exceeding unity. The likely significance of antimony and lead to ecological risk at AOPC 1S was estimated to be minimal because of the low reported occurrence of antimony in the soil samples collected from AOPC 1S, and that the EPC for lead is below the stationwide statistical background value for lead. 7.3.2.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC IS, the following can be concluded. • No COCs were identified in the soils at AOPC IS. • The total cancer risk,using state parameters for the U.S. FAS restoration/- maintenance supervisor and U.S. tour guide scenarios, is less than the NCP's point of departure (10-6) at 2.3 x 10"'and 5.0 x 10'7,respectively, and the HI for both scenarios is less than 1. • The ERA estimates the ecological risk for the soil at AOPC IS to be low. • No further action for the soils of AOPC IS appears warranted. The HHRA estimated the total cancer risk for the U.S. FAS habitat restoration/- maintenance supervisor and U.S. FAS tour guide scenarios at AOPC IS to be less than the NCP's point of departure (10-6), and the HIs for both receptors are less than 1. The • ERA estimates the overall ecological risk to be minimal. Fate and transport simulations indicate that there is a potential for three reported compounds (anthracene, phenanthrene, and ammonia) in soil to affect the groundwater at the AOPC at concentrations above the groundwater screening criteria. These simulations suggest that ammonia may reach surface waters at concentrations in excess of the groundwater screening criteria at a hypothetical point located approximately 50 feet from the AOPC. However, as indicated in the ERA, ammonia at these concentration is believed to pose little to no risk to marine ecological receptors; therefore, no further action is recommended for AOPC IS. 7.3.3 Findings, Conclusions, and Recommendations for AOPC 2 — IRP Site 6 This section presents the findings for soil, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for IRP Site 6, AOPC 2. • page 7-30 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/162000 4.07 pm on 1Wos0010v orvolkvyvylb\co1Sine orshwctron 7Witwc07o ooc CLEAN II CTO.0151/0197 Date: 0622/00 Section 7 Findings, Conclusions, and Recommendations 7.3.3.1 SUMMARY OF FINDINGS Findings on the nature and extent of COPCs are as follows. • Only one sample had VOC concentrations reported above detection limits (4-methyl-2-pentanone at SB6-20-05). • Di-n-butyl phthalate (SB6-20-07 at 0.5 to 1 foot bgs)was the only SVOC reported at a concentration above detection limit. • PAHs were reported above detection limits but not at elevated concentrations in soil. The PAH with the highest frequency of detection was indeno(I,2,3-cd)pyrene. • PCB concentrations reported above detection limits consisted of Aroclor 1248 and Aroclor 1254,both reported at SB6-20-08 at 2 to 2.5 feet bgs, and Aroclor 1260 at SB6-20-04 at 0.5 to 1 foot bgs. • 2,4-Dinitrotoluene, 2,6-dinitrotoluene, and n-nitrosodiphenylamine were reported at concentrations above detection limits at SB6-20-07 at 0.5 to 1 foot bgs. • Reported ammonia values for soil samples collected from AOPC 2 ranged from less than 0.2 to 3.3 mg/kg. • Three metals (cobalt, lead, and zinc) were reported at concentrations above statistical background. Zinc was reported at a concentration above the geochemical background in one sample. The lateral and vertical extent of COPCs in soil at IRP Site 6, AOPC 2 have generally been delineated to nondetect or a general decreasing trend. The lateral and vertical extent of metals in soil have generally been delineated to background, a general decreasing trend, or to the site boundary. Step-out soil samples were collected and analyzed as a result of COPC concentrations in soil samples in excess of screening criteria. An evaluation to ascertain whether COPCs in soil at IRP Site 6 AOPC 2 represent a potential future threat to groundwater was conducted for 25 analytes (3 SVOCs, 5 PAH compounds, 3 PCBs, 13 metals, and ammonia). The transport model simulations, assuming a 50-year time period, indicate that ammonia may affect groundwater above the groundwater screening criteria at the AOPC and at a hypothetical point of discharge into the marine environment, located 50 feet from the AOPC. The total and incremental excess lifetime cancer risks, derived by using U.S. EPA or Cal-EPA carcinogenic toxicity criteria, to the U.S. FWS habitat restoration/maintenance supervisor and the U.S. FWS tour guide at IRP Site 6, AOPC 2 were estimated below the NCP's point of departure (10'). Exposures to soils and to the inhalation of volatile compounds migrating from the groundwater to air were quantified for the two receptors at 4.7 x 104 and 1.0 x 10-7, respectively. The HI associated with exposure to a U.S. FWS habitat restoration/maintenance supervisor and to a U.S. FWS tour guide at IRP Site 6, AOPC 2 is estimated at less Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 7-31 6/162000 4 07 pm tm\\sCos0010v onvaikvyvyib,cto151vse Orsh\sect on_T 1ee\sec07.O.0ot CLEAN II CTO-0151/0197 Date: 0672/00 Section 7 Findings, Conclusions, and Recommendations • I than 1. HI estimates below unity indicate that systemic toxicity is unlikely for both receptors. The risk for exposure to lead in soil is considered negligible based on the industrial scenario results of the Cal-EPA pharmacokinetic model. Resultant blood lead concentrations are below the lead concentration of concern of 10 µg/dL for both receptors. Results of the ERA indicate that lead showed an HQ value exceeding I (HQ of 12) for the robin, which was used to represent omnivorous birds, with the primary exposure pathway for lead being through incidental ingestion of soil. However, after comparing these values to background conditions and to the range of TRVs, they did not appear ecologically significant. 7.3.3.2 CONCLUSIONS AND RECOMMENDATIONS Based on the findings for AOPC 2, the following can be concluded. • No COCs were identified in the soils at AOPC 2. • The total cancer risk, using state parameters for the U.S. FWS restoration/- maintenance supervisor and U.S. FWS tour guide scenarios, is less than the NCP's point of departure (l0-6)at 4.7 x 10-'and 1.0 x 10-7,respectively. The HHRA also indicates that the HI for both scenarios is less than 1. • The ERA estimates that the AOPC has a low potential for ecological risk. • No further action for the soils of AOPC 2 appears warranted. The HHRA indicated that the maximum cancer risk under the assumed scenarios is less than NCP's point of departure (le) and the HI is less than 1, and the ERA has indicated a low potential for ecological risk. AOPC 2 is, therefore, recommended for no further action. 7.3.4 Findings, Conclusions, and Recommendations for Groundwater — IRP Site 6 This section presents the findings for groundwater, including results of fate and transport evaluations and risk assessment, followed by conclusions and recommendations for the groundwater of IRP Site 6. 7.3.4.1 SUMMARY OF FINDINGS FOR GROUNDWATER — IRP SITE 6 Findings on the geochemistry of groundwater at IRP Site 6 are as follows. • Groundwater is present at a depth of approximately 5 feet bgs at the site. • The shallow groundwater flow direction for IRP Site 6 (and vicinity) is toward the east-northeast, with an overall gradient of 0.002. The apparent flow direction at IRP Site 6 may be attributed to the closeness of the pond and channelways in the NWR located to the south-southwest portions of the site. ) page 7-32 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 616/2000 4 07 pm Im\4Cpt0010Ytorwii4yyvyDwto151Yse OrMyKtpn juotmsoc07.43 Ooc CLEAN II CTO-0151/0197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations • The detected anion and cation concentrations and the reported TDS values suggest that the shallow groundwater below IRP Site 6 is saline in nature. Therefore,the shallow groundwater would not serve as a source for beneficial uses without prior treatment. • Recorded DO concentrations from the five temporary well points indicate that the groundwater underlying IRP Site 6 has DO values ranging from 3.16 mg/L to 9.23 mg/L. • ORP values measured in groundwater indicate that the shallow groundwater environment beneath IRP Site 6 is characterized by moderately to highly reducing conditions. Findings on the nature and extent of COPCs in groundwater are as follows. • Three VOCs(carbon disulfide, chloromethane, and methyl-tert-butyl ether)were reported at concentrations above detection limits in IRP Site 6 groundwater samples. Chloromethane was not reported at concentrations above the COP WQO or U.S. EPA AWQC for saltwater in any of the groundwater samples collected at IRP Site 6. No COP WQO or U.S. EPA AWQC for saltwater exists for carbon disulfide or methyl-tert-butyl ether. • 4-Chloro-3-methylphenol was the only SVOC reported at a concentration above detection limit only in one groundwater sample. This concentration was below the COP WQO 6-month median. • Two PAHs, fluoranthene and pyrene,were reported above detection limits. The concentration for pyrene (0.3 µg2) exceeds the COP WQO for human health (30-day average) for total PAHs of 0.0088 µg2. • Of the seven PCBs groundwater samples were analyzed for,none were reported above detection limits in IRP Site 6 groundwater samples. • Only I,3-dinitrobenzene was reported above detection limit in one out of the eight groundwater samples analyzed for nitroaromatics and nitramines at IRP Site 6. No COP WQO or U.S. EPA AWQC for saltwater exists for 1,3-dinitrobenzene. • Of the five groundwater samples collected at IRP Site 6 and analyzed for perchlorates,none had perchlorate concentrations reported above detection limits. • Twelve metals (antimony, arsenic,barium, cadmium, cobalt, copper, lead, manganese,nickel, selenium, vanadium, and zinc)and hexavalent chromium were reported above detection limits in groundwater samples collected from IRP Site 6. Of the 12 metals, 8 metals (antimony, cadmium, cobalt, copper, lead, manganese, nickel, and zinc) and hexavalent chromium were reported at concentrations above statistical background. Cadmium, copper,nickel,and zinc concentrations were above the COP WQO 6-month median concentration and the U.S. EPA AWQC for saltwater concentration. Lead and hexavalent chromium concentrations were above the COP WQO 6-month median but below Draft RSE Report, IRP Sites 4, 5, and 6,WPNSTA, Seal Beach, CA page 7-33 6116/2000 4 07 pm tm 1%0000I Cnncr NttwvetWcto 151 vae t>reft WCLon_7M,xt%secO7-0.Oct CLEAN II CTOO151ro197 Date: 06/22/00 Section 7 Findings, Conclusions, and Recommendations the U.S. EPA AWQC for saltwater. No COP WQO or U.S. EPA AWQC for saltwater exists for cobalt or manganese. Fate and transport model simulations indicate that pyrene, hexavalent chromium, cobalt, copper, lead,nickel, and zinc might continue for 50 years to affect groundwater above the groundwater screening criteria at IRP Site 6; however, only copper and zinc significantly exceed the groundwater screening criteria at the site. Furthermore, the simulations indicate that only ammonia might affect groundwater at a hypothetical point of discharge into the marine environment, located 100 feet from the site; ammonia concentrations at the site after 50 years are negligible because of transport away from the site. Results of the ERA indicate that eight compounds in groundwater exceeded the water quality criteria: ammonia (HQ of 3.0), antimony (HQ of 3.0), cadmium (HQ of 18), hexavalent chromium (HQ of 2.1), cobalt (HQ of 1.6), lead (HQ of 2.5), nickel (HQ of 6.9), and zinc (HQ of 132). If marine organisms are exposed to groundwater, cadmium, nickel, and zinc may represent a risk to sensitive marine life. Based on results of groundwater fate and transport simulations, it is unlikely that marine organisms would be exposed to deleterious concentrations of these metals as a result of groundwater at this site. 7.3.4.2 CONCLUSIONS AND RECOMMENDATIONS COPCs in groundwater include eight compounds (ammonia, cadmium, hexavalent chromium, cobalt, lead, nickel, and zinc) present in the groundwater of IRP Site 6 at concentrations that may pose a risk to sensitive marine life. Fate and transport modeling indicates that concentrations of pyrene, hexavalent chromium, cobalt, copper, lead, nickel, and zinc in soil could continue for 50 years to affect the groundwater of the site. Fate and transport modeling indicates that only ammonia could affect groundwater at a hypothetical point discharge located some 100 feet from the site. Because ammonia is the only compound that has the potential to migrate from the site during a reasonable period of time, no further action appears to be warranted for groundwater at this site. page 7-34 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/16/2000 4 07 pm im Nsdos0010YWrvoliek v avylbnCo151 vie oendifC on 7Wmsec07-o Ooc CLEAN II CTO-0 151/0197 Date: 06122/00 Section 8 REFERENCES American Society for Testing and Materials. 1994. D3441-94. Standard Test Method for Deep, Quasi-Static, Cone, and Friction Cone Penetration Tests of Soil. . 1995. Tier 2 Guidance Manual for Risk-Based Corrective Action. Appendix A, RSCA Spreadsheet System and Modeling Guidelines Version 1.0. Prepared by Hohn A. Conner et al. Groundwater Services, Inc. ASTM. See American Society for Testing and Materials. AccuTek. See AccuTek, Inc. AccuTek, Inc. 1995. Analytical results for soil samples collected in 1995 from IR Site 4. A.T. Kearney, Inc. 1989. 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Toxicol. and Pharmacol., 24:24-29. page 8-4 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/1Dr2900 11:57 am trm r Y,Ivytb10o151no Ore wocuon f exhsecObe ooc CLEAN II C70-015110197 Date: 0622100 Section 8 References Mitchell, M. 1997. U.S. Fish and Wildlife Service, Seal Beach National Wildlife Refuge. Personal Communication. 11 August, 12 November. Montgomery Watson. 1997. Addendum No. 1 to Draft Technical Memorandum No. 1, Hydrogeologic Investigation for the Alamitos Barrier Reclaimed Water Project (ABRWP). Prepared for Water Replenishment District of Southern California and Orange County Water District. April. Morton, P.K., and R.V. Miller. 1981. Geologic Map of Orange County California, showing mines and mineral deposits. Bulletin 204 (Plate 1). California Division of Mines and Geology. Naval Energy and Environmental Support Activity. 1985. Initial Assessment Study, Naval Weapons Station, Seal Beach, California. NEESA 13-062. February. . 1990. Addendum to the Preliminary Assessment (Initial Assessment Study) of Naval Weapons Station, Seal Beach, California: Part 1. August. NEESA. See Naval Energy and Environmental Support Activity. OCWD. See Orange County Water District. Orange County Water District. 1998. Facsimile transmittal of general and well location information, water levels and analyses, Information Request No. 3110. 07 May. Pain, D.J. 1995. Lead in the environment. In Handbook of Ecotoxicologv. D.J. Hoffman, B.A. Rattner, G.A. Burton, Jr., and J. Cairns, Jr., eds. Boca Raton, Florida: CRC Press. Lewis Publishers. Regional Water Quality Control Board, Santa Ana Region. 1995. Water Quality Control Plan, Santa Ana River Basin. California Environmental Protection Agency. Regional Water Quality Control Board, Central Valley Region. 1998. A Compilation of Water Quality Goals. California Environmental Protection Agency. March. RWQCB, Central Valley Region. See Regional Water Quality Control Board, Central Valley Region. 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Framework for ecological risk assessment. EPA 630/R-92-001. Risk Assessment Forum, Washington, DC. page 8-6 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 6/19/2000 11:57 ern yn n1nip ylb=151 Y1e OreHteect.on_GYestuecO60 OOC CLEAN II CTO-0151/0197 Date: 06/22/00 Section 8 References . 1992d. Water Quality Standards; Establishment of Numeric Criteria for Toxic Priority Pollutants, States Compliance Final Rule. Federal Register 57(246):60848. . 1994. Guidance for the Data Quality Objectives Process (Final). September. . 1995. VLEACH: A One-Dimensional Finite Difference Vadose Zone Leaching Model. Center for Subsurface Modeling Support. . 1996a Preliminary Remediation Goals (PRGs), Second Half 1996, Region IX. 01 August. . 1996b. Data Validation Standard Operating Procedures for Polychlorinated Dibenzodioxin and Polychlorinated Dibenzofurans Analysis by High Resolution Gas Chromatography/High Resolution Mass Spectrometry. U.S. EPA Region IV, Science and Ecosystem Support Division, Office of Quality Assurance. September. . 1996c. Vadose Zone Leaching Model, Center for Subsurface Modeling Support. Version 2.2a. June. . 1997a. Health Effects Assessment Summary Tables (HEAST). Washington, D.C. . 199Th. Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants for the State of California, Proposed Rule. Federal Register 62(150):42160. . 1998a. Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities. Appendix A: Chemical Specific Data, last updated 9/17/98. EPA350-D98- 001 B. . 1998b. The U.S. EPA TEF Values. Office of Research and Development, NCEA (http://wvwv.epa.gov/ncea'dchem.htm). 01 June. . 1998c. U.S. EPA Region IX Preliminary Remediation Goals. 01 May. Website http://wwrw.epa.goviregion09/waste/sfund/prg/ . 1998d. 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Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA page 8-7 6/122000 11.57 am um n:vtavy1000151 Mae oranlaect.on etextlaat06-O Doc CLEAN II CTO-0151/0197 Date: 06122/00 Section 8 References Western Division Naval Facilities Engineering Command. 1976. United States Naval Weapons Station, Seal Beach, General Development Map, Area 3 Map,Utilities. Scale 1 inch = 400 feet. Drawing No. 6037385. December. . Yeh, G.T. 1981. AT123D: Analytical Transient One-, Two-, and Three-Dimensional Simulation of Waste Transport in the Aquifer System. ORNL-5602. Oak Ridge National Laboratory, Oak Ridge, Tennessee. • page 8-8 Draft RSE Report, IRP Sites 4, 5, and 6, WPNSTA, Seal Beach, CA 5/1 9/2000 1 1:57 it,tm n Nwvytbttto1511rse ersftwei,m_lueetWe011-0.00t Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ATTACHMENT 3 CITY OF SEAL BEACH COMMENT LETTER TO WEAPONS SUPPORT FACILITY RE: "DRAFT SITE EVALUATION WORK PLAN, INSTALLATION RESTORATION SITES 4, 5, AND 6 - WEAPONS SUPPORT FACILITY", LETTER DATED APRIL 27, 1998 Draft RSE,IR Sites 4,5,and 6.EQCB 17 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 April 27, 1998 Department of Navy Weapons Support Facility, Seal Beach Attn: David Baillie, Environmental Director 800 Seal Beach Boulevard Seal Beach, CA 90740-5000 Dear Mr. Baillie: SUBJECT: CITY OF SEAL BEACH COMMENTS RE: DRAFT SITE EVALUATION WORK PLAN, INSTALLATION RESTORATION SITES 4, 5, AND 6 - WEAPONS SUPPORT FACILITY The City of Seal Beach has reviewed the above referenced document and is in general agreement with the proposed work plan. The work plan will better define the appropriate actions to take to eliminate existing potential adverse impacts to the residents of the City of Seal Beach and to employees of the Weapons Support Facility at IR Sites 4, 5, and 6. The overall structure of the document is well organized, with the Executive Summary being particularly helpful to the general reader. The Executive Summary would be more helpful to the general reader if Tables 4-1, 4-2 and 4-3 were also presented here. These tables are invaluable in allowing the general reader to: obtain a broad overview of the problems at each site; understand the decisions which need to made; what inputs affect those decisions; the boundaries of the proposed studies; the decision rules for determining human and ecological risk assessments; the limits on detection errors; and the proposed sampling and evaluation programs to be conducted at each site. The City also supports the following proposals contained within the RSE Work Plan document: o The proposed sampling design set forth in Tables 4-1, 4-2, and 4-3. Draft RSE,IR Sites 4,5,and 6.EQCB 18 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 ❑ The proposed Leaching and Saturated Zone Transport Evaluation Methodologies set forth in Section 7.2.1 and 7.2.2, as presented on pages 7-2 and 7-3. ❑ The proposed avoidance of a potential archaeological site within Site 4, by avoiding the appropriate roadway segment during the field soil sampling program, as set forth on page A1-24 of Appendix A, "Draft Field Sampling Plan". In regards to IR Site 4, the City supports the following proposed actions, as set forth in the Draft RSE Work Plan: ❑ the proposed leaching analysis proposed as part of the fate-and-transport analysis for COPCs identified in soils. ❑ the use of a residential exposure scenario to conduct the human-health risk assessment. ❑ the preparation of an ecological risk assessment for that portion of the site adjacent to the National Wildlife Refuge. ❑ the proposed number of samples at each of the site sampling stratums; the center of the road; the road shoulder; and, at the accumulation area of AOPCs 1 and 2. In regards to IR Site 5, the City supports the following proposed actions, as set forth in the Draft RSE Work Plan: ❑ the tidal influence study to determine groundwater flow direction and to estimate the hydraulic gradient. ❑ the collection of interior site soil samples to define the lateral and vertical extent of COPCs, in order to close a major data gap. ❑ an unexploded ordnance (UXO) survey, to provide an assessment of UXO at the site and provide access to perform the appropriate soil and groundwater sampling proposed. Inclusion of the required qualifications for personnel conducting the UXO survey is helpful in providing a better understanding of the background of the personnel which will be conducting this survey. ❑ conducting a limited radiation walkover survey, to assess the presence of radioactive material at the site. ❑ an ecological risk assessment to fully characterize the potential exposure pathways for chemicals of potential ecological concern (COPECs) to migrate to the adjacent National Wildlife Refuge salt marsh and mudflats. ❑ an increased number of sample locations, 40, to allow for a more uniform coverage than the simple random sample of 20 locations would allow. In regards to IR Site 6, the City supports the following proposed actions, as set forth in the Draft RSE Work Plan: Draft RSE,IR Sites 4,5,and 6.EQCB 19 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 D additional characterization of the stratigraphy and subsurface geology. o a tidal influence study to determine groundwater flow direction and to estimate the hydraulic gradient. o the use of residential preliminary remediation goals (PRGs) for characterization of organic compounds in soil, and the use of the California Ocean Water Plan water quality objectives as screening criteria for organic and inorganic COPCs in groundwater. ❑ a fate-and-transport evaluation of COPCs identified in soils that, due to the thin vadose zone, are likely to have reached groundwater. O an ecological risk assessment to fully characterize the potential exposure pathways for chemicals of potential ecological concern (COPECs) to migrate to the adjacent National Wildlife Refuge salt marsh and mudflats. O the proposed trenching at AOPC 1 to expose the burn/disposal trenches. This is necessary to accurately characterize the presence and levels of metals, VOCs, SVOCs, and PCBs. ❑ the proposed hexavalent chromium analysis. However, the City does have some concerns, and the Navy is requested to consider these concerns in finalizing the subject report: (1) IR Site 5, page 4-45, indicates human-health risk assessments will be based on two exposure scenarios: tour guide and habitat restoration/maintenance supervisor. The City is concerned that a residential exposure scenario is not proposed for this location. Although it may seem a remote possibility that this site would ever become available for a use other than that a discussed within the draft RSE Work Plan, this possibility should not be precluded. If it is unreasonable to undertake that level of analysis at this time, due to the speculative nature of the future use of the site, that determination should be clearly stated within the document. In addition, any future documents relating to this site should clearly and explicitly discuss this determination, and indicate if the site is eventually released for a non-natural resource protection use, the Navy will restore the site to the appropriate residential standards. (2) IR Site 5, page 4-53, indicates "Because of the potential for the Site 5 fill to be transported to the salt water marsh, sediment along the edge of Site 5 may be sampled." (Emphasis added). The City strongly requests this language be changed to "shall be sampled". In addition, the City requests that the Navy consider sampling along the edge of Site 5, adjacent to the National Wildlife Refuge shoreline at each of the proposed sampling grids which contain a shoreline area, as indicated on Figure 4-12, page 4-47. This would result in the taking of an additional 11 sediment samples. (3) IR Site 6, page 4-59 at the bottom of the page, indicates "Risk estimates will be based on COPCs identified in soil at the site and two exposure scenarios: tour guide and habitat Draft RSE,IR Sites 4,5,and 6.EQCB 2 0 Draft Removal Site Evot'i'tion (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 restoration/maintenance supervisor." However, page 4-57, Screening Criteria, indicates "Screening criteria used for delineation of the extent of organic compounds in soil will be residential PRGs or an apparent trend." The City is confused in the apparent discrepancy between these two statements, and would request that residential PRGs be used throughout the analysis at IR Site 6, for the same reasons discussed above regarding IR Site 5. (4) IR Site 6, page 4-66, "Metals, VOCs, SVOCs, and PCBs in Soil", first sentence, first line, references IR Site 5. Please correct. (5) IR Site 6, Appendix Al, "Draft Field Sampling Plan", page Al-24, indicates that an archaeological survey was conducted by Archaeological Resource Management Corporation (ARMC) in 1980, and the survey reports do not indicate the presence of an archaeological site at IR Site 6. City staff has reviewed the referenced report and is concerned that the ARMC report indicates: "In sum, most of the area of the property could not be walked over in the standard procedure of equally spaced, parallel transects. The procedure used instead, simply stated, was to walk over all areas that it was possible to walk over. At the time of the survey this consisted of portions of the east half and the south end of the property (see figure). While there was very little standing water in these areas during the survey, most of the area was to soft to walk across. The west half of the property was underwater." Given the uncertainty as to which portions of the survey area of 160 acres were actually observed as part of the walkover survey, and additional discussion within the ARMC report regarding the observance of shell deposits, although located among areas of considerable man-caused disturbance, the City is concerned that additional precautions should be taken regarding potential cultural resources at IR Site 6. The City requests implementation of a discovery procedure and worker instructional presentation regarding potential cultural resources at IR Site 6, similar to those programs established for the Background Study Sampling Areas. Those requested procedures and presentations are set forth in "Archaeological Resource Protection Plan for the Background Study Sampling Area at Naval Weapons Station, Seal Beach, Orange County, California ", prepared by Chambers Group, Inc, and dated August 1995. Thank you for allowing us to comment on the draft "RSE Work Plan" for IR Sites 4, 5, and 6. If you have any questions or require further information, please contact Mr. Lee Whittenberg, Draft RSE,IR Sites 4,5,and 6.EQCB 21 Draft Removal Site Evaluation (RSE)Report - IR Sites 4, 5, and 6, Naval Weapons Station Environmental Quality Control Board Staff Report July 26, 2000 Director of Development Services Department, (562) 431-2527 at your earliest convenience. He will be able to respond to any additional questions which you may have regarding this matter. Sincerely, /s/ /s/ Marilyn Bruce Hastings David Rosenman, M.D. Mayor, City of Seal Beach Chairman, Environmental Quality Control Board cc: City Council Environmental Quality Control Board Archaeological Advisory Committee City Manager Director of Development Services Draft RSE,IR Sites 4,5,and 6.EQCB 2 2