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Home My WebLink AboutCC AG PKT 2010-03-22 #SAGENDA STAFF REPORT DATE: March 22, 2010 TO: Honorable Mayor and City Council THRU: David Carmany, City Manager FROM: Terrence Belanger, Interim Director of Public Works SUBJECT: ARCO CONTAMINATION CORRECTIVE ACTION PLAN RECOMMENDATION: The City Council authorize the City Manager to sign the comment letter recommending modifications to Arco's Preliminary Corrective Action Plan (CAP). BACKGROUND: In 1986, the Orange County Health Care Agency ( OCHCA) determined that Arco, the responsible party, released hazardous material (gasoline products) from the underground storage tank at the property located at 490 Pacific Coast Highway. The tanks were replaced. A subsequent leak around the dispenser island and gasoline pipelines was noted in 1990. ARCO commenced a series of additional efforts to cleanup the shallow groundwater affected by hydrocarbons starting in 1997 and has continued such efforts under supervision by OCHCA. In 2009, OCHCA informed the City that Arco would be installing a temporary soil vapor extraction system to address detections of gasoline contamination in the form of soil vapors affecting the streets in the surrounding community of Bridgeport. OCHCA required the work because soil vapor probes (installed for the first time in 2009) detected high levels of benzene. Benzene is an organic chemical compound that is an additive to gasoline and is a known carcinogenic. Concurrently with the new soil vapor investigation and interim off -site remediation, ARCO supplemented its prior on -site cleanup activities with the installation of additional on -site wells and investigations. Due to the nature of the project and scope of work outside city staff expertise, staff retained an environmental engineering consultant (Dudek) to study the matter and provide recommendations to the city. An environmental law specialist from the City Attorney's firm, Richards Watson Gershon, was also brought in to provide legal advice to city staff. Since November 2009, city staff has been Agenda Item S Page 2 working closely with OCHCA, Dudek, City Attorney's Office, Arco representatives and the community to evaluate the health and safety risk caused by the soil contamination. Under the direction of OCHCA, as an immediate remediation, Arco has collected soil samples underneath a number of homes in the Bridgeport area and indoor air samples to evaluate human health risk. Arco also installed a permanent soil vapor extraction system in the streets neighboring the gas station. Many community meetings have been established and held since November 2009, some hosted by Arco and many provided by the City. In recent meeting in January 2010, a Technical Advisory Committee was formed by the community. The Technical Advisory Committee consists of five members of the Bridgeport community with actual work experience in soil and or groundwater remediation. Pursuant to California Code of Regulations, Title 23, Chapter 16, Article 11, §2728, the OCHCA requested Arco to submit a preliminary Corrective Action Plan (CAP) to permanently remediate the soil, soil vapor, and groundwater contamination. A CAP is a detailed document describing how Arco will clean up off -site (Bridgeport area) and on -site (gas station). As part of the CAP, the State Code allows for a public comment period. On February 16, 2010, Arco submitted a preliminary CAP to OCHCA. On February 23, 2010, OCHCA informed all interested parties that the comment period has commenced. The deadline for public comment is March 31, 2010. The CAP outlines five basic topics: • Review of historical investigations (how this all started) • Site Assessment (contamination limits) • Proposed clean -up levels for site (soil vapor, soil and groundwater) • Four alternative remediation methods i. Full Site Excavation and Off -site Soil Vapor Extraction ii. On -Site Air Sparging and On- and Off -Site Soil Vapor Extraction iii. On -Site In -Situ Chemical Oxidation and On- and Off -Site Soil Vapor iv. Extraction On -Site Dual Phase Extraction and Off -Sae Soil Vapor Extraction F • Summary and cost evaluations of the four alternatives. See attached power point summary of the CAP. The City's environmental engineering consultant and the Bridgeport Community Technical Advisory Committee have reviewed Arco's Corrective Action Plan. The following summarizes staff's comments on the CAP: The CAP does not properly describe the total area impacted by hydrocarbon contamination from the ARCO service station. In particular, it understates the extent of groundwater contamination that extends into the Bridgeport community. Page 3 • The CAP does not provide an adequate set of clean -up goals for groundwater and for soil remediation. A more stringent set of clean -up goals should be provided as a measuring point for the cleanup. • The CAP's four alternative remedies are weighted by ARCO in favor of Alternative No. 3, which essentially involves the injection of a chemical compound (an oxidant) designed to react and destroy hydrocarbons in the groundwater and soils beneath the gasoline service station site. This weighting ignores a number of uncertainties concerning the sub -soil chemistry of exactly how injecting such a chemical would in fact work and uncertain over how many such injection points would be necessary in order to effectively remediate the site. If one factored into these uncertainties, then the potential cost of ARCO's preferred remedy could increase substantially. • ARCO's remedial alternative no. 1, the on -site soil excavation remedy, appears to be the one remedy that does not involve a lot of unknowns and uncertainties. It is also the remedy that can clearly be achieved in the shortest time frame of all four remedies. Given the potential cost increases necessary to compensate for the uncertainties in the other three remedies, it appears that alternative no. 1 is also a "cost- effective" remedy. Please note that a community meeting is scheduled for March 18th, and staff may revise the draft letter to reflect information from that meeting. RECOMMENDATION: The City Council authorize the City Manager to sign the comment letter recommending modifications to Arco's Preliminary Corrective Action Plan (CAP). SUBMITTED BY: NOTED AND APPROVED: fi* -1AU41 — - - — Terrence Belanger, Interim David Carmany, City Manager Director of Public Works K) Attachments: A. Draft Comment Letter on ARCO CAP B. OCHCA letter announcing public comment period for ARCO CAP C. Powerpoint summary of CAP ATTACHMENT "A" Draft Comment Letter on ARCO CAP f March 23, 2010 Via E -mail (Amartinez @ochca.com) and Regular Mail Mr. Anthony F. Martinez Senior Engineering Geologist Orange County Environmental Health Orange County Health Care Agency 1241 East Dyer Road Suite 120 Santa Ana, CA 92705 Re: ARCO Station No. 6066: Comments on Preliminary Corrective Action Plan for 490 Pacific Coast Highway, Seal Beach, CA OCHCA Case No. 86UT206 Dear Mr. Martinez: This will provide the comments of the City of Seal Beach ( "City ") on the Preliminary Corrective Action Plan ( "CAP ") submitted by Stantec on behalf of Atlantic Richfield Company ( "ARCO. "). For the reasons stated below, the City urges that the Orange County Health Care Agency ( "Agency ") require significant modifications to the CAP. We describe initially our questions and concerns with respect to the CAP as presented and then our requested modifications to the CAP. This letter represents the final comments of the City as of this writing, however, the City reserves the right to supplement these comments if it obtains additional data pertinent to the CAP. I. CONCERNS ABOUT THE CAP AS PRESENTED A. The CAP Inadequately Describes the Scope of Contamination Caused by Leaks at the Station, Particularly with Respect to Groundwater The State Water Board regulations require that a CAP contain an "assessment of impacts" [of the leaking tanks], including: "the physical and chemical characteristics of the hazardous substance or its constitutions" including the potential for migration. ARCO provides a section entitled "Assessment of Impact" including a discussion of the extent of hydrocarbon impact in groundwater. (CAP, Section 3.0). But, that Section fails to adequately describe the aerial extent of contamination, particularly the extent of contaminated groundwater. S7296- 0309 \1214477v2.doc On page 3.7, the CAP states, "Cumulative groundwater data indicates that the extent of the benzene and MTBE plumes have been adequately assessed within practical limits to the north using well B -13, to the west using well B -14, to the southwest using well B -6, and to the east using well B -20." But, groundwater quality data obtained through the off -site hydropunch investigation indicate that this statement is inaccurate with respect to the extent to the benzene plume west of well B -14. On October 22 and 23, 2009, benzene was detected in hydropunch groundwater samples collected from the 6 to 12 foot interval in BP -2 and BP -7 at concentrations of 260 ug/l and 2.1 ug/l, respectively. Gasoline Range Organics (GRO) was also present in these samples at 11,000 ug/l and 1,100 ug/l. In contrast, no benzene or GRO was detected above a reporting limit of 2 ug/l in a groundwater sample collected from well B -14 on November 12, 2009. The explanation of this apparent discrepancy between the initial hydropunch data and simultaneous groundwater data may be in well construction and the depth interval sampled by the wells. Well B -14 is screened from 5 to 20 feet below land surfaces (BLS). This 15 foot long well screen appears to provide dilution of hydrocarbon contaminants present at shallower depths. Additionally, the CAP notes in section 3.4.1. when discussing hydrocarbon impacts to soil, ".. . impacted soil was present primarily from a depth of two feet bgs to 10 feet bgs." Longer well screens allow for the mixing of clean water from deeper intervals with shallower water during purging. Well B -17 on -site has consistently had the highest concentrations of dissolved hydrocarbons and occasional indications of separate phase hydrocarbons. It is significant that well B -17 is screened from 5 to 15 feet BLS. Comparison of groundwater samples from on -site well B -2 (screened from 5 to 30 feet BLS) and the recently received data from hydropunch groundwater samples collected from borings SB -9 -14 (approximately 30 feet south of B -2), SB -15 -18 (approximately 20 feet northeast of B -2), and SB -16 -18 (approximately 30 feet northwest of B -2) provides further evidence of the dilution that is created by the 5 to 30 foot screen intervals. GRO was detected in well B -2 at a concentration of 85 ug/l on February 8, 2010. Benzene was detected in well B -2 at 2.3 ug/l. In contrast, GRO was detected in the surrounding hydropunch samples collected to depths of 14 to 18 feet BLS at concentrations ranging from 11,000 to 180,000 ug/l while benzene was detected at concentrations ranging from 360 to 2,000 ug/l. Since the CAP was written additional data from off -site wells has been made available. The new wells are screened from 5 to 20 feet BLS. Wells B -22 was constructed adjacent to BP- 2 and well B -23 was constructed adjacent to BP -7. Well B -21 was constructed adjacent to BPI 1. In all cases the longer sample interval from the permanent wells resulted in lower concentrations than those observed on the hydropunch samples collect from the 6 to 12 foot depth range (Figure 6). Groundwater samples from the new wells still appear to be diluted. Based on these results of groundwater samples collected between 6 and 12 feet BLS, the extent of groundwater containing benzene above the Maximum Contaminant Level (MCL) of 1 ug/l is greater than depicted on CAP Figure 12. Additional shallow wells with shorter screen intervals are necessary to thoroughly characterize the extent of hydrocarbon contamination in groundwater. It is important to accurately identify the extent of the shallow groundwater S7296- 0309 \1214477v2.doc contaminated by benzene and potential Light Non - Aqueous Phased Liquids (LNAPL) in the capillary fringe, as this may be a source of benzene in vapors detected in the Bridgeport neighborhood. To illustrate the failure to adequately assess the impact of contamination, the City's environmental consultant, Dudek, has prepared Dudek Figure 1 attached hereto. Dudek Figure 1 shows the off -site spread of hydrocarbon contamination (measured in terms of "GRO" or "gasoline -range organics ") in groundwater based upon ARCO's own hydropunch data. B. The CAP Fails to Identify the Appropriate Soil and Groundwater Cleanup Levels In Section 4 of its CAP, ARCO states that groundwater underneath its service station is not part of any designated "potential beneficial use" for municipal drinking water purposes. This is a misreading of the appropriate Santa Ana Regional Board Basin Plan, that expressly provides that water in this area has a potential beneficial use for "municipal" purposes that are used for community, municipal, or individual water supply systems. (Santa Ana Regional Water Quality Control Board, Basin Plan, Chapter 3, Table 3 -1 at p. 3 -42 (entry for "Orange" groundwater management zone noting that "MUN" designation is a potential beneficial use). Thus, the appropriate groundwater cleanup level should be the applicable state (or federal) Maximum Contaminant Level (MCL). In the case of benzene, the MCL is 1 gg/L. 1. Reliance on Remediation by Natural Attenuation (RNA) in Three Alternative Remedies ARCO states in Section 4.3 of the CAP that based upon "groundwater data trends" the plume [of contamination] appears to be stable and RNA [remediation by natural attenuation] mechanisms appear to be active at the Site." (CAP, p. 4.2). Moreover, ARCO suggests that for three of the four remedial alternatives (Nos. 2 -4) that once the on -site SVE system reaches a point of "diminishing returns" then it will be shut down and post - remedial monitoring will "document the ability of RNA to further -reduce any remaining residual contamination." (CAP, p.5.4, p.5.5). But, ARCO offers no supporting data or explanation to support the conclusion that RNA mechanisms are active at the site. Stantec's reports have noted a correlation between elevated GRO concentrations in the subsurface and a combination of high CO2 and low 02 concentrations in soil gas. But, there are soil gas points sampled in areas of moderate soil contamination that do not exhibit this combination. Moreover, relative levels of fixed and biogenic gases alone are not sufficient to demonstrate RNA. This is particular true for benzene, which is the primary chemical of concern at this site, and which is not necessarily one of the most biodegradable of the gasoline hydrocarbons. Many of the aliphatic fractions of gasoline (except cyclic and highly- branched compounds) are more biodegradable than the aromatics (such as the "BETX" compounds). Moreover, even among BTEX compounds, benzene is not generally recognized as the most biodegradable. Before RNA is selected as the passive remedy for contamination left in place following three of the four active alternatives, ARCO must perform a more rigorous demonstration of the natural biodegradation of gasoline hydrocarbons and, particularly, benzene. This demonstration 3 S7296- 0309 \1214477v2.doc could include in -situ or ex -situ microcosm studies or the identification of organisms and redox conditions that the literature indicates are capable of degrading benzene. At a minimum, the pathway(s) by which hydrocarbons are assumed to be degrading should be identified. The inorganic chemistry and biogenic gas data presented to date are not adequate to do so. Reported Oxygen Reduction Potential (ORP) values are consistently in the +400 millivolt range, suggesting the presence of highly oxidizing conditions that do not appear to vary with common inorganic redox indicators. Finally, the City notes that ARCO's current optimism about the state of natural attenuation mechanisms is contradicted with its conclusion in the 2005 CAP, which reached the exact opposite conclusion. In the May 4, 2005 CAP, Delta Environmental wrote on behalf of ARCO that: "To be considered an acceptable alternative, monitored natural attenuation would be expected to achieve site remedial objectives within a time frame that is reasonable compared to that offered by other more active methods. Although natural biodegradation may be occurring beneath the Site, the removal /reduction rate is low..." (ARCO Corrective Action Plan for Facility No. 6066 at p. 12 (Delta Environmental, May 4, 2005)(emphasis added). The City recognizes that ARCO has completed a significant amount of additional work since May 2005, but nowhere does ARCO explain why in 2005 its consultant concluded that the reduction of hydrocarbon contamination was "low" and its new consultant now concludes that the natural reduction of such contamination is "active." 2. Appropriate Soil Cleanup Levels In Section 4.2 of the CAP, ARCO states that it proposes to rely upon U.S. EPA Region 9 "Preliminary Remedial Goals" (which Region 9 now terms "Regional Screening Levels ") for setting a soil cleanup level. Even assuming that EPA's screening level is in fact appropriate to utilize as a cleanup goal, ARCO selected a table from EPA's "Regional Screening Levels" for residential (or industrial) soils. ARCO should have selected the alternative table for soils to protect groundwater. That table is Table 1 attached hereto, and shows significantly lower levels for benzene and other gasoline - related constituents than those proposed by AItCO. The levels shown in Table 1 for benzene should be utilized as the cleanup level for benzene contaminated soils on and off -site. C. Uncertainty as to the Effective Radius of Influence of Soil Vapor Extraction (SVE) Systems All four alternatives include off -site SVE and alternatives 2 through 4 include on -site SVE, yet the effective radius of influence of the SVE wells has not been determined according to guidance prepared by the Department of Defense. (USACE, 2002. "Engineering and Design, Soil Vapor Extraction and Bioventing ", Manual No. 1110 -1 -4001, US Army Corps of Engineers, 3 June 2002). 4 S7296- 0309 \1214477v2.doc To date, the only study that ARCO has produced is a radius of influence study for the off - site effects of its vapor extraction well system. This study had a limited purpose —to evaluate whether off -site sampling results were impacted by the operation of ARCO's then existing SVE system. That study suggests a radius of influence for those SVE wells of approximately 42 -45 feet. [ Stantec's letter to Orange County Health Care Agency, "Addendum to Work Plan for Interim Soil Vapor Extraction. " (10126109)]. But, Stantec's estimate of 42 to 45 feet for the radius of influence for the SVE wells appears to have been based only on vacuum pressures measured at observation wells induced by vapor extraction at wells SV -5 and SV -6. The initial radius of influence study did not consider the air permeability and flow velocity of soil gas between the wells, which is a significant factor in estimating the area that is effectively remediated by SVE. Based on the lithology and apparent moisture content of the soil, the air permeability may be relatively low and thus constitute a substantial limiting factor in actual air flow in response to pressure gradients and thus the effective area of remediation. Further testing should be done to define the effective area of remediation. Routine monthly monitoring of benzene concentrations in vapor probes (as opposed to SVE wells) already installed in the Bridgeport neighborhood should be implemented to verify the effectiveness of the SVE system. D. The CAP Underestimates the Realistic Costs of Preferred Remedial Alternatives 2 and 3 and Overestimates the Likely Costs of Remedial Alternative 1 1. Underestimation Related to Air Sparging and ISCO, Remedial Alternatives No. 2 and No. 3 ARCO underestimates the realistic costs of its preferred remedial alternatives, nos. 2 and 3. In particular, both the air spraging remedy (alternative no. 2) and the "In -Situ Chemical Oxidation" (ISCO) (alternative no. 3) remedy are premised upon the location of injection wells at a distance of approximately 30 feet apart. If, however, the radius of influence of such injection wells is significantly less than 30 feet, then the number of required injection wells (and hence, overall costs) could go up considerably. Dudek has briefly reviewed ARCO's submittal of an air sparging pilot-test to Orange County Health Care Agency contained in a March 4, 2010 letter that was submitted after the initial CAP. This letter suggests that at least for air sparging, ARCO anticipates a radius of influence of 10 -20 feet, based upon the use of this technique "at other sites." Based upon the scale shown in the CAP, Figure 19, it appears that at least some of the proposed air sparging wells are located greater than 40 feet apart, suggesting an optimistic range of 20 feet for each well. Review of the technical literature suggests that placement of the air sparging wells typically requires more wells placed more closely together. If so, then ARCO has underestimated the number of such wells that are required and thus under estimated the capital and labor costs associated with remedial alternative no. 2. ARCO's cost estimate for its ISCO alternative has another critical omission: It fails to explicitly factor in a contingency in its preliminary cost estimate, particularly for estimated capital costs of the new ISCO system. EPA Guidance on cost estimation at a preliminary phase 5 S7296- 0309 \1214477v2.doc of a feasibility study suggests that an appropriate contingency of approximately 100% be placed on the cost estimate, U.S. EPA, A Guide to Developing and Documenting Cost Estimates During the Feasibility Study at 2 -3 -2 -4 (OSWER 2000). While ARCO's cost estimate has a range of costs (lower estimate and upper estimate), most of the variety appears to be related to O &M costs based upon uncertainty in the length of operation. ARCO's cost estimation for ISCO capital costs as shown on Table 15 varies by just over 30 %, which is a far lower contingency range than EPA Guidance recommends at this preliminary stage of the project. Similarly, ARCO's estimate for the capital costs of a supplemental on -site SVE system, both for design and installation costs of on -site SVE wells, appears to have a very low contingency built into the estimate for such work. 2. Overestimation Related to Dig & Haul, Remedial Alternative 1 By contrast with its lack of a contingency cost and optimistic assumptions for its preferred alternatives, ARCO's cost estimation for its least preferred alternative, Alternative 1, is marked. ARCO's cost range for this alternative is almost $2.3 million from its "lower estimate" to its "higher estimate." This range itself is not as suspect as the fact that Alternative 1 is the most conventional of all the proposed remedies, and the one most capable of more precise estimation. The site has been the focus of a series of studies about the depth of contamination, which appears to be limited to the top 10 feet of soil. Calculation of the total number of cubic yards of soil to be removed, and the appropriate conversion of cubic yards into tons for purposes of cost estimation, is a relatively straightforward process. Yet, ARCO estimates that hydrocarbon soils to a depth of 10 -15 feet would have to be removed, generating a much larger upper range in their cost estimate for the total soil removal. This lower estimate for excavation presented in Table 13 of the CAP is a more reasonable estimate given the data that suggests that the depth of the excavation should be limited to 10 feet. ARCO's cost estimate for the on -site excavation remedy fails to integrate at all with ARCO's proposed cleanup levels for soils. ARCO proposes soil cleanup levels of either 1100 ug/kg or 5400 ug/kg for benzene in soils. While the City believes that these levels are demonstrably incorrect, if one assumes ARCO's soil cleanup level, then all of the soil data suggests that the area of soils above the 1100 ug/kg level are confined to a relatively small area near the "new" tank area principally centered around P -2 and P -1, with a second area located behind the service station and dispensers. Dudek Figures (depictions of benzene concentrations at the 0 -3 feet and 3 -5 feet bgs levels). ARCO simply does not integrate its proposed cleanup level, the existing soil contamination level, and its separate cost estimate, which suggests demolition of the entire service station and dispenser islands. ARCO does not explain why it is cost - effective to demolish the entire station rather than leave it in place and dig and haul the truly contaminated soils in other areas. ARCO's cost estimate for remedial alternative 1 is highly conservative (i.e., biased toward higher cost estimates) in several other respects. ARCO suggests that the "high estimate" of costs for obtaining Coastal Commission approval for this remedy could be $200,000. That estimate is ten times larger than the estimate for Coastal Commission approval for any other remedy, and utterly undocumented as to why the costs for a "dig- and - haul" remediation could potentially be so expensive. Similarly, ARCO includes a "loss of business payments" amounts ranging from $50,000 to $80,000 for remedial alternative 1. It fails, however, to explain why 6 S7296- 0309 \1214477v2.doc any such payment would be triggered. Certainly, ARCO cannot expect that any nearby business would be seriously inconvenienced by the presence of 6 -18 trucks per day on Pacific Coast Highway. ARCO's cost estimate does not provide backup documentation to show that it would impact businesses up to 5 months when it would presumably be spending most of that time simply digging up soil within its own property. ARCO also budgets under "project management and reporting" a sum ranging from $150,000 to $250,000. Again, this estimate is ten times higher than "project management" costs for any of the other alternatives proposed by ARCO. E. ARCO's "Effectiveness" Determination is Seriously Flawed ARCO's CAP rates all four of the proposed remedial alternatives as equally effective. Not so. If by "effectiveness" ARCO means the "theoretical possibility that each of the reviewed remedial alternatives could, over time, achieve a reduction in the groundwater contamination," then the City agrees that utilizing that extremely narrow definition of the word "effectiveness" that each of the four remedies possess that theoretical possibility. But, the City comments that the term "effectiveness" as used as part of the defined term "cost- effective" in the implementing regulations (23 Ca. Code of Regulations, Section 2720) (defining term "cost- effective "), must be broadly construed to include the concepts of "effectiveness within a defined time period" and "effectiveness in terms of certainty of removal of groundwater contaminants." ARCO concedes that only one of the proposed remedial alternatives, Alternative No. 1, is capable of effectively reducing groundwater contamination within a timespan deemed acceptable to Orange County Health Care Agency, i.e., within two years. (See Letter of OCHCA to ARCO Re: Station 6066 dated January 14, 2010, at 2 (stating that: "Mobile NAPL must be removed from this site within two years. "). Only Alternative 1, as described by ARCO, is capable of effectively removing mobile NAPL within two years. (CAP, Section 5.2.1 at p.5.3 (estimating on -site excavation and backfill will take up to 12 months for permitting and 2 -6 months of excavation and backfill activities). All other alternatives, including Alternative 3 may (or may not) be effective in achieving that goal, but none can effectively commit to that goal. Indeed, ARCO's own CAP concedes that the time period for operation of Alternative 3 could be as much as 5 years to= `account for data gaps." The ISCO portion of Alternative 3 is estimated to take as much as 12 months for pilot testing, test evaluation and reporting, and another three months of construction and ISCO injection activities. This means that the effectiveness of the field scale implementation of ISCO (per ARCO's own estimate) will not be known for 15 months after approval, and that the goal of effectively removing mobile NAPL within 24 months is at best uncertain. ARCO does not give an estimate for completion of the ISCO process, simply noting that "ISCO injections will be repeated if necessary until groundwater concentrations within the cleanup area meet the short- term cleanup goals." (CAP, Section 5.2.3, at p.5.5). In terms of "effectiveness in terms of degree of certainty" in achieving removal of hydrocarbon contaminants in or threatening groundwater, again only Alternative 1 fully meets that criteria. Excavation and backfill remedies are proven technologies that have worked for decades to achieve regulatory goals in a cost - effective manner. 7 57296- 0309 \1214477v2.doc By contrast, ARCO's ISCO process, while technically possible, is relatively problematic in terms of certainty of effectiveness in this context. In 2005, the Interstate Technology Regulatory Council published its: "Technical and Regulatory Guidance for In Situ Chemical Oxidation of Contaminated Soil and Groundwater" describing ISCO as a technology and various types of oxidants that could be utilized to implement this remedy. Critically, however, the authors noted that with respect of Mobile NAPL, the application of ISCO was "possible but challenging." (I'IRC, "Technical and Regulatory Guidance for In Situ Chemical Oxidation of Contaminated Soil and Groundwater at Table 1 -5, p. 17 (2d ed. 2005)). This is hardly a ringing endorsement of the applicability of ISCO to a Mobile NAPL situation. The Federal Remediation Technology Roundtable literature (FRTR, Table 3 -2 Treatment Technologies Screening Matrix, 2007) lists in situ chemical oxidation as "Below Average" in its screening matrix. The Roundtable listed the following additional factors in considering an ISCO remedy: High Degree of O &M intensity. High degree of capital investment. Low reliability and high maintenance. High degree of general costs relative to other options. More than 3 years to cleanup in -situ soil at a "standard" site. More than 10 years to cleanup groundwater at a "standard" site. Of course, there is a significant amount of evidence that this service station facility is far from a "standard" site under any criteria. Thus, the suggestion by ARCO that the ISCO remedy would likely take less than 5 years and is rated to be as effective as Alternative No. 1 is more a matter of wishful thinking than demonstrated facts supporting this remedy as truly "effective." To establish the effectiveness of ISCO at this particular site, ARCO must show site specific hydraulic data. The effective delivery of an oxidant (such as persulfate) is dependent on its persistence, solubility, permeation into the porous media, and contact with contaminants. Injection of an oxidant solution can drive dissolved contaminants further from injection zone if they are not remediated by peripheral injection wells. The City respectfully refers the Agency to the analysis in the attached Dudek, Observations on Site - Specific Conditions, which could impact upon the effectiveness of the proposed ISCO remedy. This is not to say that under no circumstances could ISCO work at 490 Pacific Coast Highway; rather, the Dudek analysis demonstrates that a number of site - specific subsurface soil chemistry issues need to be evaluated carefully before any selection of ISCO can be justified under the "effectiveness" criteria for this site. In sum, when considering the term "effectiveness" with respect to both time- effectiveness and with respect to a proven and clearly applicable technology compared to a technology that is at best "challenging" in the context of Mobile NAPL, the City submits that only Alternative 1 is effective in controlling and removing the sources of hydrocarbon contamination at this site. All other remedial alternatives discussed by ARCO are theoretically possible, but at best "challenging" in their application to this specific site. 8 S7296- 0309 \1214477v2.doc II. RECOMMENDATIONS FOR MODIFICATIONS TO THE CAP The City recommends that OCHCA accept the Preliminary CAP submitted by ARCO, but with the following modifications: (1) Groundwater clean -up levels and soil clean -up levels be modified to specify MCLs (for groundwater) and EPA Region 9 Screening Levels (per the attached Table 1 specific to potential groundwater impacts) for soil. (2) The CAP be modified to include the most recent data on hydrocarbon contaminants in the soils and groundwater based upon more recent (February 2010) data and also include in depictions of groundwater impacts all available hydropunch data as well. (3) The selected remedies be modified as follows: (a) Off -Site Remedy —SVE System: - (1) Noise levels from the new generator and SVE system must comply with City Ordinance No. 7.15.015 for Noise Zone 1, which regulates noise levels in the residential community. ARCO should retain an independent noise consultant and prepare an initial report followed by quarterly update reports to OCHCA on compliance with applicable noise standards. (2) Clean -up standard for an SVE system in this residential neighborhood should be the attainment of health - protective soil vapor standards. There should be no reduction, shut -down or elimination of the SVE system based upon any presumed "RNA" in the Bridgeport community given the lack of comprehensive soil chemistry data to support the possibility of natural attenuation in this area. (3) To the extent that the new draft DTSC Guidance on Soil Vapor Intrusion has applicability to the operation or maintenance of the current SVE system and standards for that system, it should be applied. (4) Any planned cessation of operation of the SVE system for maintenance activities and any unplanned cessation lasting more than 10 days should be followed by rebound effect testing that is overseen by the Agency. ARCO should submit a report within 30 days of the end of the cessation period documenting: (a) whether the cessation was planned or unplanned; (b) why the cessation took place; (c) results of the rebound effects test; and (d) if the cessation was due to an unplanned event, the corrective action ARCO has implemented to prevent a recurrence of similar unplanned events. (5) ARCO should supplement its off -site remedy to include remediation of benzene and other gasoline hydrocarbon levels above the respective MCLs that have been observed in the off -site wells and hydropunch probes. 9 S7296- 0309 \121"77v2.doc (b) On -site Remedy: The proposed on -site remedy should be modified to require the excavation of soils to a depth of 8 -10 feet below ground surface in areas where excavation is easily undertaken. ISCO injection should be utilized as a remedy for those on -site locations (underneath the service station building and underneath the dispenser island) where access is limited or would require major structural modifications to the existing station. ISCO injection should also be utilized for off - site remediation of soils in the vicinity of the service station wall. In addition, OCHCA should require that ARCO: (1) Cease any further pilot study work for air sparging on the grounds that given the site conditions and contaminant distribution, further studies and unlikely to establish a cost - effective remedy at this site; (2) Implement a full -scale pilot study for ISCO utilizing in the off -site area identified on the aforementioned map and complete the pilot study within six months. Monitoring wells should be installed at intervals described in the Dudek Observations on site - specific conditions to confirm the effectiveness of ISCO injection. (3) Provide quarterly updates to the City and Bridgeport community via flyers and mailed reports on the status of the performance of and sampling associated with on -site and off -site remediation system (4) Commit to using low- emission and carbon- efficient trucks to haul excavated soils to the appropriate disposal or incineration facility. The Agency should also require training of all truck drivers as to the proper methods of entering onto station property and properly exiting from Fifth Street to access northbound PCH; (5) Comply with City Noise Ordinance No. 7.15.05 for Noise Zone 2, which is applicable to industrial /commercial noise levels for all trucking, drilling and excavating activities; (6) Provide a backup plan for excavation if ISCO is deemed not to be effective by the Agency on the basis of the bench scale or pilot studies and commit to implement the backup plan should the ISCO pilot test not achieve 95% reduction in contaminant concentrations. (7) Submit a report to the Agency (with copies to the City and Bridgeport Community) demonstrating removal of all mobile NAPL within two years of the commencement of the on -site remediation. (8) Comply with all City permits for both off -site and on -site remediation work; and (9) Submittal to the Agency of financial assurances in an amount that is based upon the revised capital and operations and maintenance budget for the modified on -site remediation work. Financial assurances shall be of the same 10 S7296- 0309 \1214477v2.doc quality and types as required by U.S. EPA for RCRA closure and post - closure projects. The City wishes to commend the vigorous efforts of the Orange County Health Care Agency in following this site with the full attention of its staff, including Mr. Richard Sanchez, Mr. Larry Honeybourne, Mr. Anthony Martinez, and Mr. Osman Taban. The City will be available and will make its technical environmental consultant, Dudek, available to respond to any questions that the Agency has with respect to these comments. Yours truly, David Carmany City Manager City of Seal Beach Attachments: 1) Dudek Figure 1: Gasoline -Range Organics in Groundwater; 2) Table 1: EPA Regional Screening Level for Soils that Impact Groundwater; 3) Dudek Figures 1 -4: Benzene concentration levels at various soil depths; and 4) Dudek & Associates Report, Observations on Site - Specific Conditions 11 S7296- 0309 \1214477v2.doc HP-1 <100 <100 13 'N P'3�0� �w HP 1z <ioo % Ic 28 t3-20 All T-6 Groundwater Monitoring Well HP-5 'Cl 00 2 0 <50 t HP -7 11100 B-4 HP r6 m 10-100 100.1,000 3A % `210.,r250 m 10,000-100,000 --------- Hydropunch Locations 50 <10 of lion-detect '00 0 1,000-10,000 HP-9 X <100 a � • 10 000-100,000 V N > - - - - - 5'- 15'WeD Screen and Hydropunch Approximate Contours 5'- 30'Mq Scroon Contours 5'.30'WegSaeenAppmxifnaleContours Concentration 100-11000 1,000-10,000 1a 000.100,00a DUDEI( Note Figure prementil data alailaillm 9D DUatir all Of 207J10 SUbjeCl to W&On Upon la"Ir of add.hnnal data $66141 Hydropunch and Groundwater Monitoring Well Locations with GRO Concentration (pgIQ FEBRUARY 20TO enagopod Corturnauty Regional Screening Levels I Region 9: Superfund I US EPA Page 1 of 2 http: / /www.epa.gov /regionO9 /superfund /prq /index,htmI st up aced on Thursday, February 11, 2010 Region 9: Superrund = "MV, M 'tae$ You are here: EPA Home Realon 9 Superfund Regional Screening Levels Regional Screening Levels (Formerly PRGs) Screening Levels for Chemical Contaminants Regional Screening Level ;Resources ; The Region 9 PRGs have been harmonized with similar risk - based screening levels used by Regions 3 and 6 into a single table: "Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites." These updated screening levels, along with a detailed user's guide and supplementary tables, can be accessed directly on -line or downloaded to your own computer. In addition, the web site contains a Screening Level Calculator to assist in calculating site - specific screening levels. 0 Region 9- specific information regarding the Regional Screening Level Table » What's New ; ' Frequently Asked Questions Screening Level Calculator User's Guide Online Screen Level Calculator PRG (RSL) Contact Information Region 9- Specific Information RSL Tables (Last updated December 2009) The screening level (RSL) tables are available for download in Excel and PDF formats. These tables are considered ready for use. The tables contain both RSL calculations and the toxicity values that were used. For additional information please see the resources box at the the upper -right of this page. http:// www. epa. gov/ region09 /superfund/prg/index.html 3/15/2010 PDF (Color) PDF (B +W) Excel (Color) Excel (B +W) Summary Table (PDF) (9 pp,. 73.4K ) (PDF) (9 pP, 69.8K XLS XLS Residental Soil Supporting (PDF) (11 pp, (PDF) (11 pp, XLS XLS 67.2K ) 63.1K Industrial Soil Supporting (PDF) PP (PDF) 1 pp, XLS XLS Residental Air Supporting (P 44.6K) pp, (PDF 40). (8 pp, XLS XLS Industrial Air Su Supporting (PDF) (8 pp, (PDF) (8 pp, XLS XLS 43.9K) 40.3K) Residental Tapwaters (PDF) (12 pp, PDF ) (12 pp, XLS XLS Supporting 64.5K 60.3K — — Residental Soil to PDF (11 pp, PDF 11 XLS XLS Groundwater Supporting 67.1K 60.8K Chemical Specific LPDF) (8 p� (_PDFI (8 pp, XLS XLS http:// www. epa. gov/ region09 /superfund/prg/index.html 3/15/2010 Regional Screening Levels { Region 9: Superfund US EPA Page 2 of 2 Parameters 71.1K Composite Table (PDF)(78 pp, 427K You will need the free Adobe Reader to See EPA's PDF pact, 66.7K (PDF) (78 p, XLS XLS 418K view some of the files on this page. to learn more. NOTE: The 2004 version of the Region 9 PRG Table will remain at this web site in case users need to reference this historical document. However, the 2004 Table should no longer be used for contaminant screening of environmental media because it has been replaced with the more current Table above. ® Region 9 PRGs 2004 Table (PDF) (16pp, 962 K) ® User's Guide /Technical Background Document PDF (29pp, 284 K) http: / /www.epa.gov /region09 /superfund/prg /index.htm] 3/15/2010 Regional Screening Level (RSL) Sod to Groundwaler Supporting Table DECEMBER 2009 12/10/2009 Key I - IRIS P - PPRTV A = ATSDR. C - Cal EPA, X = PPRTV Appendix H = HEAST, J - New Jersey: E = Environmental Cmena and Assesamenl Office, S = see user guide Secadn 5,1.= see user guide on lead, M = mutagen. V = volaille, F - See FAG 0.29, c =cancer - =Chafe .m . inny C1 •- .-h.,.. Q, a1nY .. 0.1 ..- �____�_ __.•_____.___ .. _ .. _ ontomihard - - - -- - -- - -•• -• oxux • ••• --• •-- and Ctxxncel•e ••..- „•....... ifielydormaeon �.„,..,.....,,. 1111.. r,,.. ,,.., . ,,,, -w , e - - m- nraacn may exceea n el Risk 61946' csat (see HoneaneefHszerd users uuide): Mlax 551. values I ■.. are based on DAF =1 o SFO k IUR k RFDc 11 k RfC1 k v n ebwi• I Inhainfion 5141 I soon Inhalation Tatel ad ` e :-•...• :' °• '• UWL ., r. ".. , O : 0gA uwt O9A uglL' L ' '.: i,$1� a` }. %' w.N "1:s+° ex.rr'.�;. , :. -: $ 1 CAS No e • e e o mute• (mglkg -d0. ) r IuWmtl r (fig day) ( 1m) c en Al AR 159644.5 1 BE -02 C 51E -08 C 1 5E -01 I 9.7E 3 + 55 +09 ' ,' "' Sf +09 u r AcePhata yde 3058at9 -1 75-07-0 879-03 I 2 29-06 1 40EA3 1 9 DE-03 1 V "• 7.7E�OD; •; : •' , 7.7E +00 1,SE!02•, -" . •� ' 16Et�, tv . =)n .t,:J,a-s•. ±•5;"d.•r` 4" 0.9 .¢,,,:r, ACatoehlor 34256-02.1 2hE 2.2E 189+01 189 +01 r , ., • „.`j 4j,7:A,: `•-r'•; .• Azolone 6784 -1 2 OE -02 9OE-01 I 1 31E+01 AV 7 39102 , " I 3 36154 7 39+02 6AE+ti4 2.2E+04 ,�.'yd'E Iaa 2 ;I� car Acetone C a rm 75 -88-5 3 OE -03 P 6.0E -02 P V ' .. 1.1E+02. 139 •' 5. Ef01 ., , •*icV� `' i ,,bra ;• Acetonlbda a 75 -056 98.88.2 1 OE-01 8 OE-02 I V •. 1r "• `'.7ei,1jT„,'� Ace eminolluorana 98.2- 53 -3 38E+00 C 19E -03 C I V •3:7E+09 , ". 48E-02 - 8Fs02 .. ''3.79+03 ••' �Dt".`°`,i°+va', x i:'8 E'rb '''+ %: i Acrolein Acrylamide 107 -02 -a 79-051 4 5E+00 I 13E -03 1 5 OE-04 2 OE-04 1 2 OE -05 I V I "„ 4 BE+D1 159 92 , •t, , ;1, ;H q2" 7:39 *40 "' 4, -02 ;' • 4. 7 8Ed0D •�a , tR + q yr ' ' �. ') ybc Acid Aclylon trfie 797a� 107 511E -01 I 10E-03 I r 1.6E+04 /' 189+04,1aE j r�!q} °,'�Ta'l Adlponllnle arhbr -13.1 111.89 -3 5 4E -01 1 6 8E -05 1 4 OE-02 A 2 OE -03 I V 6 OE-03 P 7 ' 2, 2 ' 4'SE OZ' 1 "69+03 - •. - 4 29 • A 29!00 .. •.. • 9 - `::, ,irk,,.•°k`w, ' I :, n 1597280.8 569 -02 C 1 DE -02 1 '1.2E+00, ' • -• 1.2E +00 .79+02 .7 +02 ' II.OE+00 .'1 °I.aY 8E+1"'• •:1�Y3¢�;17SA3'''' dworb Aldlrar'bSulfone 11646.3 104t18B•4 1 OE -03 tOE-03 I 1 3.7E+01 3,7 :; r ,. 37Ef01 •''/4.79+81 69:1 #a• ,Q .03rH9�''a °±' ,,k�'7 -00.2 17E+01 1 4BE -03 1 3DE -05 I 4O'E -03" 03 11 +DO 1" t;PV 1y AJIVI Alcohol All Chloride 74223 -644 107 -18-6 107-051 2 f E -02 C a OE-06 C 25E -01 5 OE-03 I I 1 OE-04 X 1 OE-03 I V &19±03 .. ' : • • i 8E +02 "29+00 '• ' 91EfD3 '• . , 1,8E +02 _ ; ' . E;OC, �• �'fi'' +k Aluminum .3 8•tE -01 $ 5 -01 ' 2 +00 .' 2.1 +00 ' • ° Q) c , ?'y° •; "wii, uminumPhosphWa Amdro 7129 -90 5 20859.738 67485.29.4 10E+00 4OE-04 P 5 0E -03 P 1 3.79+ 3'7 1,5E +01 " 1.69/+01 'k1 .' Sr,S'H17k"�S''y, t.•' :- ` _ , ; ,v,.,r "x •v , 3 OE-04 I 1,1E+01 19+01, s: -, 14' E X:�ftiS) < • a :L i" atryn 834 -12.8 9 OE -03 I "' „u 0. Aminobiphonyl,4- Amino 1181 rn- 9267.1 591.27 -5 21E+01 C 6OE -03 C B OE-02 P.8E+03 3.3E +02' . •3.29-09; .$.ZE-03 8.3E+92 ' ',,. {; • •s,+ • s. . { p, inophenol, P 12330.8 - • • 2 89+09 .,zh'j;��'�'" y,." -y^�g' .;�„• • s Amy Ammonium Perchlorate 33089.61 -1 7780 2 OE -02 25E -03 P 1 7 3E +02 .. '9.1Efg1 7 9E 2 "' - 8.1E+01 - •A:7`si'k',,; �+'x,+', Ammonsan Sullamale -88.8 70 1 2.6E+0i 2,8 +Ot - ,",' -- - • $YI ,„.; Amlea 7773-08-0 8253-0 5 TE -03 1 1 GE-06 C 2 0E -01 7 DE -03 I P 1 OE -03 I 7.3E+03' 1.2E+01• •;• -' ' 1,2E +01 2 8E+02 7.3E+0i • 2.$9+02 'g.,•...= g = Ml mehOc 7440 -36.0 4 OE -04 1 - 1:5E+01 _ 1.5E+01 8.0E +00 �`3f,, •`, 8 "BE' -01 "5'� L MOrtiuny Penloxde Mlaroriy Polasshan Tortola 1314.80.9 11071-151 5 OE•04 9 OE-04 H H ' 1.8E +01: ' 3.3EWi • ' 1 9+07 , <s: ,s ,7E-p - 11 r� Yom, „ •„r ,,-4 .r y =, Antkmy Talraxxb 1332616 4 OE-04 H 1.6E ;Ct ,3.8E+91 1.5E+01' _ ,;,avyawm ; �; r .sp �:, ±• �t e Aelknorly Thoxde 130984-4 2 09-04 I , Apollo Aramfle 7411520.5 140578 2 SE -02 1 7 1 E-08 1 139 -02 5 OE-02 I H 4.8E+02. "• -' ' . ' 7E ' • •, .:.' . A iE1O2 , - • ' g $:EE7!^ I„�°# • ki Amenic,Inorganic 744038.2 1 SE+00 1 43E -03 1 3OE-04 I 1.5E -05 C ,79+00 2 +Op • 1 BE +03 • 414E -02 - 4,6E 1.1 +01 89+03 = ;'' 6 C1E102 `.:7°'' '� xrc Arsine Amours 7784.42-1 3 5E-08 C 5 DE-05 I s' - -02 ,. 1.3E -01..� 1.1E+91 , ; ..:,: 1.$9;91, 1.9Ef01 i•' a E x+11 •k' f,�E w; t - t ' S +a,aF' }: r 7667514.8 9 OE -03 1 33E+02" • 9 99402 y '•2£ E r1a =S' �, :•'ftb Asulam Alraana 9397.71 -1 1912.249 23E.01 C 5 OE -02 1 1.8E+03: • -- . "; ' 1, BE ; "'. 1 0.Y a ;y ` Auramino 4924" B BE -01 C 2 5E -04 C 3.5E-02 1 „ 2 :9E -01- • , , 2,9E -01 ,' 1.9E+03 , BE " r ; ' � • •1.3Ei03 9.0E +00 ,rj,;'�1,!)�.dd.., " ,SE.• ° "�° vamisckn8l 7 02 r • .: ?. -02. : �` rt`« y, r, '7= y1 ; g ;; p48nxane Barium 65195553 103 -33.3 744039.3 11E -01 1 3 1E-05 1 4.0E -04 209 I V 1,5E+01. „7.59+01 8:19 -01 ;1:89 -01 V • 1,2Fr01 , +: p26E+Qt�vrNi• " 1 , "rx �Yg� -01 1 509-04 H 7.3E +03 - 739 2DE +03506#0 �Yle Ba id 114 -26 -1 4312143-3 r 4 OE -03 9 09.02 I I 4.5E+02 1 4,9+03 1,59102 ' 1 %E+03 8895837.5 2 59.02 1 8'19+02 - .'91602 " Bensfin Bommyl Benlazon 156140.1 2507.89-0 3OE -01 509-02 1 I 1.18+04 ' 1:89 +D9 =, i•YE+W c ., 4.11 +O3 E' ,. 8( f9it. ?- yr •" �iA• ° Los�gpa�; a• 3 OE-0Z 3OE 1 1:19 +03. 1.1E 3: , A -07� • 9C sY? ; Ban aldehyde Benzene 10032 -7 7143.2 5 5E -02 I 7 8E-06 1 -01 4 OE -03 I V 1 311E -02 I V 3.7E+69 , ' 3, 6+03 1.2E+pD, : �.2E p1" '4.19 -01 159+02 ', A .'A : s,- •• r ,• 0.r",.. •' r A ".n;i•+; ozone , 639+01 49+91 6.AE+00 ;; Benddine BenmicAcid 9287.5 B56S•0 2 3E+02 1 6 7E -02 1 3 DE -03 4 OE+00 1 M I 8.4E-05 •' . '8;48 -05'. ,11E+02' I SF+05 , 1:19 - : Banzobkhlonde 9&07.7 1 39+01 1 V S 29-09 . ," . • ." •. 5 - ., ,. +.- r ;, +.1Ey °r '�li 8anryl Alcalwl Benzyl Chloride 100-51.6 1 OE -01 P 3.7E +0.7 3 E , .w•0. iuK ;`w• -.';. ir8,8�, i;1i Y�: ;r `, a tiium and compounds 10a4q -7 744047 -7 1 7E -01 1 4.9E-05 C 2 4E -09 1 2 OE-03 2 OE -03 P 1 OE -03 P V 1 2 OE-05 I 4 OE -01 ' • 9,99.02 7 99.02 " ', 7.3E+01 R.1Q+D11 2 OF+QO .8,'/ e 4 • Li;' Q � .•., &drin 739+01 7.8E+01 4 OEf00 dr);v45 8 +09• «•2 r' 'II i , A Billonox 141862 42576-02.9 1.0E-04 909 -03 I P 8.7E +30 _ , ,. " .: ,4,3E+92 87E10A : 1,3E+02 1' �.$E- gd,'r;:,•,.q. -.:, ZlE��-:Lrt'�''',y`v� Mon 82857.04 -3 7 5E -02 I 5 SE+02 - 6 SE402 p apq �j'. r;+�,tii (,•S. Page 1 of 11 HP -1 <2 2 • VP43 -2 ; VP-44-2 \ . j VP-47 -2 t VP42 -2 <22 �`' ; VP-W-2 VP41 -2,: �•<2 s® 1 rca.un.•'• �• ,, <7 9 • /`<1 9 , �.. \\ \ VP-08 -2 ;1 , SB -13 -1 5-2� ¢ /' VP-45-2 <1 9 <�1,8 } SB =14 w " H242 VP,4U -2 <2 \ •a^ ! i HP--11 SB$ /<87� �• i , <2 >• \ "' 18 • s VP-55-2 •' ' • p� \ VP-24-2,:— •' t VP -14 -2 SB4P1 52 VP- 12 -2' <2p SB5 �, , ''1 �� <22 22 ' .<2 SB;23,�+170 SB-12 -1 52 � VP38 -2/ �. /•. VP- 25-2 VP-23-2 SB -11. •140, ' ® "7Q 49/53 1 <2 VP-39-2' � . <2 5 HP -2 200 ; • SB 10 1.5=2 — ` \�" � t \ <21 1 • <0'81/ <21 'SB22 -1 5 -2 • <2 2• \ %• ` , • 18 L SQ6 -1 5 -2 ' VP -54 -2 y/ \ \ ,S8;7 „152' • 23/ <2.2s r 47/19 yp6 • : - ! t,t : <21 /. ;,• VP-26-2 VP, -152 - 1 •. 590/280' "•' 1 Q5 % \ /; <2 <19 isSB -15 SB20•, �SB2 • / ` i / HP -7 SB21 E+,•!1'6 VP27 -2 <21 • SBM18 1'5 -2 • SB -19'1 52 �. VP-37-2 1 8 . HP -6 • 380%120 <2 s 6 2 <22 �• \ •, <7}8 ` • �� \ /'� %/ % % /.” \ • \ / i % /SV10S • � • �2� � •S�28' 3 VP 8 -2 SB9-152 <VP22- 2/.< <0 95/ 2 B 7<4// SV•8 Sv31- P -17 -2 VP-36-2 VP-28-2 , ,' 130 ` <33� <2 2 • / •,� \ �' HP-8 HP 8 , P -21 -2, SV4 \ S V\ • SB-1-1 5-2," _ A<2 P<1 8 ' i 34/0 2 V2•SV t r J sS VP- 52 -2-•° ' -•. \ % %VP29 -2 WVP -20 -2 \ ,: ,•25, VP30 -2 I` / / <18•,/, e2 6F' . / i / • .` �: \• \ �• _ VP32 2 % \ \ %' f/ • <2 2 try/ <2:2 % 1 % <17 /VP -19 -2 % / \ <21 VP-,31-2 >/ VP34 2 rs . ; f <Pa0 \` \ •� <2 <25 Benzene Concentration (pglkg) • < 10 and non detect • 10400 • 100 -1,000 NOTE SB- 12 -1.5 -2 [4 9/5 3 Sample ID (SB -12) - Sample Depths (1 5 - 2) - Concentrations (4.9/5 3) Concentration Levels 10-100 k 100 -1,000 w VP-49'? , <1 7/, <19 r rte. / • r; e 0 375 75 �Fnl •„ � � D U D E K Note Figure represents data available to Dudek as of 3/3110, subject to revision upon receipt of additional data. FIGURE 1 Benzene Concentrations in soil 0 -2 feet below land surface 6651 -01 MANCH2UIU Bridgeport Community DRAFT HP -1 <1 6 19 <2 -1 VP -074 VP -02 <2 \ ` j VP411,\ <21 \\ to* 1 f <2 1 \VP45�4 <1 8 52 1 *f•VP.40-4 i/ V -244,_ VP -14-0 100% � VP'-38-4 / \ \ ` //' VP= 25 -0\ \� VP -23-4 <1 8 VP-39,4, \ . // <2 2 \ <1 8 HP HP-5 / . VP -26-4 '<2 1 , VP -15-0 g6.7 <2 ` %i rs \ 290 • 3,4p • / \ \ VP -274 ' / \ \ . ;fir HP -7 •, • /\ <P87 \ \ <21 •� <26 / 35 • SV� • \ \`• \ / % /' • VP -224 \ <83 Sy" VF 364 <1 6' sv -kNi 50C / /VP -284 \ f' •'/ � ♦ S' <21` <3�/ \ , " e VP-214 \<81 SV-6 .1, Y� VP- 204Y•' 1 \ <2 1 / / \ VP,9 VP-32-0 ; Y VP -184 \ . HP-9 VP-334 rr \ / \,a " VP -354 - ✓ ` r i \ , , <2 2 ` e „ \ <1 8 f 0 27 s as — • Fed ',� X D U D E K I Note Figure represents data available to Dudek as of 3113110, subject to revision upon receipt of additional data 6667 -01 MARCH 2010 56., VP-55 <2 t••, us:on i. t . V2-54 270 SV�1ly— .100' -• -�. ., VPS14 „-~ <16 \� VP -50-\4 ; / Benzene Concentration (Ng /kg) • < 10 and non -detect • 10-100 • 100 -1,000 O 1,000 - 10,000 NOTE SB- 124.5 -5 23 -12 Sample ID (SB -12) - Sample Depths (4 5 - 5) - Concentrations (23 -12) Concentration Levels - < 10 and non -detect 10 -100 100 -1,000 1,000 - 10,000 FIGURE 2 Benzene Concentrations In soil 4 -5 feet below land surface DRAFT HP -1 <1 9 '\ ,E <1 8 ' r usno°w y/ \ + � \ \' ✓r ` r' % r/ // % • < H /P r ' \ \ /r i�• r r ,`+, f `\•, , , ¢" ! ' 1 � 2;B 9 0SB 11, ; 3HP-11 B�, lS6 -14 <2 3 u. , t 00 ,w- S85 0/2,900 1;4001' s' S8-7 O 3 0 %1; 200/1 ?10i 0 L s, ' • .uuem ,2;'; 3,70, 0 /5,200`, SB -10 HP 4,000/ 1,8000 130 i , SB -16 O SB -22 i \ ,': // \ •` 8,800/8,300• e- is HP5 \ :`, O . , SB;15 1 002 !i / / r ` y W ,, , �<430 SB -20 <t 5 SB 2 ® r: / , ` �¢ /r'`' \ \ . / 8101 „ / • <1 8 }: ,n' 8,300/5,000/8,100 1,800 SB i \ HP.-6 SB -17 090/330; °'11800 14,000/13,000_:', ,,y HP$'� ` ttj r /dj r / ' T` � 1. / r` \ ♦ ��; r `�✓; r cuxn.va <18 aw ra 'kh\ <2' /J Benzene Concentration (jig/kg) • < 10 and non -detect • 10-100 0 100 -1,000 O 1,000- 10,000 0 10,000+ NOTE SB -10 4,000/1,800/1,000 Sample ID (SB -10) Concentrations (4,000/1,800/1,000) t e. (sample/split-sample/duplicate-split-sample) Concentration Levels < 10 and non -detect 10 -100 Lu A� 100 -1,000 1,000 - 10,000 10,000- "UD Note Figure represents data available to Dudek as of 313/10 subject to revision upon receipt of additional data. FIGURE 3 Benzene Concentrations in soil7 -9 feet below land surface Bridgeport Community ` DRAFT wmemw \i /" F1,i -72.% `, \ 3 ( HP-11 S� S9 4 • ,•,� \ _ SB-8 42 t� f 1 X10 SB •11;' i < mama, '} 1 (� \ ` , • / . \ H -2 j •i� SB-7 •.. 8Q•7G€ ` i i , i ;\ r . • ♦ \ ✓/ ' ` \ \\\ SB -20•" off., k a =p. . , 6.0o0np31, ' • / . 1-' y HP-7 �, 48-18 SB 1 SBA 88-22 ,.HP-e \ \ ; ,/ • <7 8 '•� <` .t5'� 01.900 ,.7000V 1;6 I r 0138-9 \\ \ ,•/ ,\ • /, //� °*, •.W�,w 1.600 \/ / �+• \ \ ` ;/ ./ cam_ 1 � i .0 � '� ",' • 7 ea 3�dFeet / ' %' �• DU D E K Note- Figure represents data available to Dudek as of 313/10, subject to revision upon receipt of additional data. FIGURE 4 Benzene Concentrations In soil 10 -10.5 feet below land surface 6611 -01 rrnrvrizvlo Bridgeport Community DRAFT ATTACHMENT "4" Dudek & Associates Report: Observations on Site - Specific Conditions (Will be provided under separate cover at a later date) ATTACHMENT "B" OCHCA letter announcing public comment period for ARCO CAP Excellence -�- °Integrity Service COUNTY OF ORANGE HEALTH CARE AGENCY PUBLIC HEALTH SERVICES ENVIRONMENTAL HEALTH PUBLIC NOTICE DAVID L. RILEY DIRECTOR DAVID M. SOULELES, MPH DEPUTY AGENCY DIRECTOR RICHARD SANCHEZ, REHS, MPH DIRECTOR ENVIRONMENTAL HEALTH Preliminary Corrective Action Plan, dated February 16, 2010 Posting Date: February 23, 2010 Site Name: Site Address: City, Zip Site Case #: OCHCA Contact: Phone #: e -mail: ARCO #6066 490 Pacific Coast Highway Seal Beach, CA 90740 86UT206 Anthony Martinez (714) 433 -6260 aartinez@ochca.com MAILING ADDRESS: 1241 E. DYER ROAD SUITE 120 SANTA ANA, CA 82705 -5611 TELEPHONE: (714) 433 -6000 FAX- (714) 754-1732 E -MAIL: ehealth@ochca com Pursuant to the California Code of Regulations, Title 23, Chapter 16, Article 11, Section 2728, the Orange County Health Care Agency ( OCHCA) hereby provides public notice of proposed cleanup activities at the above referenced site. A hazardous materials release occurred from an underground storage tank system at the site referenced above. A site investigation was conducted to determine the actual or potential effects of this release. Using the information obtained during this investigation, a preliminary Corrective Action Plan (CAP) to abate the effects of this release has been prepared by the responsible party. This plan has been submitted to the OCHCA for review and approval prior to its implementation. OCHCA staff is currently reviewing the preliminary CAP, and is accepting comments from the public until March 31, 2010. Public comments will be taken into consideration prior to approving a CAP for this site. The CAP proposes to remediate the contamination by conducting one of the four remedial alternatives described in the plan in addition to the existing off -site soil vapor extraction system. The four alternatives described in the preliminary CAP are as follows: 1) Excavation and removal of contaminated soil; 2) On -site soil vapor extraction and in -situ chemical oxidation; 3) On -site soil vapor extraction and air - sparging; and, 4) Dual-phase extraction. The next public meeting to discuss this site will be held on Wednesday, February 24, 2010 at the Mary Wilson Library at 707 Electric Ave., Seal Beach. OCHCA will hold a public meeting specifically to discuss and take public comments about the Corrective Action Plan in March. Another public notification will be issued when this meeting has been scheduled. To submit written comments on the CAP, please write to the OCHCA contact person listed above at 1241 E. Dyer Rd., Suite 120, Santa Ana, CA 92705, or by e-mail. Information and decisions concerning the preliminary Corrective Action Plan are available to the public for inspection upon request. To review or obtain information regarding this site, contact OCHCA's Custodian of Records at 515 N. Sycamore, Santa Ana, CA 92701 or call (714) 834 -3536. The CAP can be found at: https: / /geotracker .waterboards.ca.gov /esi/ uploads /geo_ report /4623523638/TO6059W372.PDF. You can find other information about this site at: https: / /geotracker.waterboards.ca.gov /profile_ report.asp ?global_ld= T0605900372. ATTACHMENT "C" Powerpoint summary of CAP • ARCO's "Preliminary Corrective Action Plan" (CAP) Feb. 16, 2010 Describes plan to clean up off -site (Bridgeport) and on -site (gas service station) properties DUDfK What is a "CORRECTIVE ACTION" and how does it fit in with the whole clean -up process? The State set up a "UST Fund" to pay for precisely what's happened here: an underground gasoline tank that has leaked, impacting soil and groundwater. (Ca. Health & Safety Code) D UDEK 0 � Review of historical investigations Site Assessment (where's the contamination ?) Proposed Clean -up Levels for Site Proposed Remedy must be "cost- effective" (for groundwater protection) DUDEK A ¢a Will CAP adequately protect human health, safety and the environment? Will CAP restore or protect current or potential beneficial uses of the water. (Cal. Reg. Title 23, Sec. 2725 (c)? DUDEK A Agency (Orange County Health Care Agency) must allow for "public notice" in variety of manners. Public Notice period ENDS on March 31, 2010. Provide Comments to: Anthony Martinez, Orange County Health Care Agency E- mail: AMartinez @ochca.com Snail- mail Anthony Martinez Orange County Health Care Agency 1241 East Dyer Road, Suite 120 Santa Ana, CA 92705 Phone: (714) 433 -6260 (less preferable) DUDEK Agency (OC Health Care) must "concur " `in CAP and can order, modification or rejection of CAP. G ARCO must modify CAP if directed to do so by Agency ARCO must "monitor, evaluate, and report the results of implementation of the CAP" to the Agency. ARCO must "modify or suspend cleanup activities when directed to do so by the regulatory agency." - DU'DEK Wimialirnwa6viv a Site Background: _(old history, some geology notes of soil types in area) (12 pages, 2.1 2.12). Assessment of Impact of Release: (types of gasoline, extent of gasoline spill in aerial conditions), soil vapor, groundwater and soil impacts. (9 pages 3.1 -3.9). Determination of Cleanup Levels: (separate "suggested" cleanup levels for soil vapor, soil and groundwater). (2 pages, 4.1- 4.2). Feasibility Study: 4 different alternatives that vary only as to the different types of "on- site" remedies. ALL off -site (residential community) remedies include continuation of "Soil Vapor Extraction" System) (8 pages, 5.1 -5.8). Summary: page (5.8) concluding that alternative No. 3 (on -site treatment by injection of "chemical oxidant" into subsurface soils) is capable of meeting cleanup goals and achieving lowest -cost cleanup. DUDE'K Jillot Stud A Plan to Test Feasibility of Preferred Remedy (injection of oxidant into gasoline service station soils) (2 pages, 6.1 -6.3). No "implementation plan" for CAP because final remedy not yet selected, Promise to give public notice, consultant's hand - washing from any responsibility, and footnotes. (6 pages, pages 7.1- 8.1 -9.1 and 10.1-10.3) DUDEK Soil Vapors (Off -site in Bridgeport Community): Stick with approved cleanup level of 40 Ug/M3. Soil: Use EPA Region 9 standard, "Preliminary Remediation Goals" for "residential/industrial" soils. What ARCO does NOT tell you, however, is that there R5 more MI U LHdH one Z5UL UI such YUdIZ5 (now called by EPA "Regional Screening Levels"). Type of Benzene Benzene Comments Screening (parts per million) (parts per billion) Level (per EPA) Residential Soil 1.1 ppm 1100 ppb ARCO uses Industrial Soil 5.4 ppm 5400 ppb ARCO uses Soil- .0026 ppm 2.6 ppb ARCO does Groundwater NOT use protective "Groundwater [beneath the ARCO Service Station] is exempt from municipal supply below the Site. Therefore, there are no beneficial uses of groundwater threatened by the current groundwater contamination. Based on groundwater data trends, the plume appears to be stable and RNA [Remediation by Natural Attenuation] mechanisms appear to be active at the Site. Therefore, Stantec proposes the elimination of the NAPL [Non- Aqueous Phase Liquid] and demonstration that remaining concentrations will continue to decline to background 'levels over time due to RNA as the groundwater cleanup goals for the site." DUDEK 0 R� ARCO'S Groundwater Cleanup Level There is None. Just Cleanup the "Non- Aqueous Phase" Gasoline and Monitor to Ensure "Natural Attenuation." July 2000 - June 2001 Temporary Dual Phase Extraction (weekly & monthly) November 2001 Proposed Permanent Dual Phase Extraction September 2002 July 2003 Temporary Dual Phase Extraction (monthly) August 2003 September 2003 Vapor Extraction (Well B -17) April 2004 Remedial Excavation (Dispenser Island Only) DUDEK May 2005 Proposed Oxygen Release Compound (ORC) July 2006 - May 2008 Over -Purge Events (Well B -17 only) July 2008 Proposed EnvironClean Surfactant Injections July 2009 - November 2009 Temporary Soil Vapor Extraction December 2009 — Present Temporary SVE DUDEK Proposed Soil Vapor Cleanup Levels Methane - 3,476,973 fag /m3 Benzene - 40.3,pg/M3 Gasoline Vapor - 147,000 pg/M3 DUDEK Proposed Soil Cleanup Levels EPA Region 9 Preliminary Remedial Goals (PRGs) Residential (pg/kg) Industrial (pg/kg) Benzene 11100 57400 Toluene 570001000 45, 000, 000 Ethylbenzene 57400 271000 Xylenes 6307000 217001000 MTBE 437000 220,000 TBA none none DUDEK Y} No Groundwater Cleanup Objectives were proposed by Stantec. Stantec concluded that there are, ... no beneficial uses of groundwater threatened by the current groundwater contamination." DUDEK A Bioventinq - soil treatment technology Soil Flushing soil treatment technology f: Monitored Natural Attenuation - groundwater sampling Passive /Reactive Treatment Walls - groundwater treatment technology Groundwater Extraction - groundwater treatment technology Physical Barriers - groundwater and soil vapor containment technology DUDEK iI 1. Full Site Excavation and Off -site Soil Vapor Extraction 2. On -Site Air Sparging and On- and Off -Site Soil Vapor Extraction 3. On -Site In -Situ Chemical Oxidation and On- and Off - Site Soil Vapor Extraction 4. On -Site Dual Phase Extraction and Off -Site Soil Vapor Extraction DUDEK Remedial_ Alternative Timeframe Decision 1. Excavation Exc. 4 -6 mos. Rejected + off -site SVE < 1 yr 2. AS + SVE 2 -5 years Pilot Test 3. ISCO + SVE 2 -5 years 4. DPE + SVE 2 -6 years Pilot Test Rejected DUDEK Air in Air injection well (air sparging) WN C- MI Air pollution control equipment pollution X- Water We- #4 IN SITU CHEMICAL OXIDATION (ISCO) Prey -phase Petroleum Product Extraction Well Diill'''I EWIbit X41 Typical 5ingie -Pump DPE System ppro pri opor TTreaats tment later Discharge tegsnd: Vapor Phase 1:1 Adsorbed Phase Each alternative is evaluated by these criteria: Level of protection of health and groundwater • Reduction of contaminant source i.e. hydrocarbons Ease of implementation ® Cost Effectiveness • Compliance with regulatory guidelines • Short term effectiveness • Long term effectiveness Impacts to community Environmental impacts • Impacts on water conservation DUDEK ARCO rates all 4 alternatives as equally protective However, they are only equally protective if they are thoroughly implemented. €=' It is not clear at this stage what density of air sparging, ISCO or DPE wells will be necessary to reach all gasoline Excavation provides greater certainty of addressing all gasoline DUDEK "' ARCO rates all 4 alternatives as equally effective in reducing hydrocarbons Again this is accurate if each alternative is executed with enough rigor to reach all hydrocarbons E Air Sparging, ISCO and DPE all rely on unseen migration of fluids in the subsurface to work Extensive application and monitoring required to be certain these alternatives are working Greater certainty with excavation DUDEK ARCO rates excavation hardest • Station demo Shoring, trucks, permits ISCO rated easiest, but proposed number of wells may be fewer than needed rg Air Sparging and DPE rated relatively easy DUDEK [-,-j ISCO estimated at $857,500 to $1.7 million Air Sparging estimated at $857,500 to $2 million ;� DPE estimated at $1.2 million to $2.2 million -� Excavation estimated at $3 million to $5.4 million Much greater uncertainty in first 3 than in excavation P# Excavation costs lower than assumed noxni evil camrilir►rr based on '} Excavation ranked 1St ISCO 2nd Air Sparging 3rd DPE 4 t DUDEK �? . � � Sri•. ARCO rates all equal +� Accurate. if all alternatives are executed thoroughly and successfully DUDEK `= Excavation rated worst • Noise, dust, vapors, traffic, business interruption Neglects longer implementation of other alternatives Neglects perception of impact to property value DUDEK All 1 �•� , 1 1 E E t z E m DUDEK t'... '1 1 "on kiF 00 r s• .i �»Tr •�. t ��w ,y» G a. 1 .j� • ygAygA11 j � �� ` i DUDEK vP -44.a r HPA1 e.. . if NX\ 3 VP, m HP -12 ✓ 2 '� / \ ✓! VP -74.2 22 N k \ c1 ' VP- 42 / °f x -525.2 1.. -21 3•z 0 P4 ?� HP -$ � � � t ° t ,r�� liP- 2fe•7y , \ '� 2 /j, ` J \ -zz �` r it 'r �u' `v156i VP VP-aaz VP11 2. J HP-9 i ✓ < ae ,17 ' VP 484 l n •2 ', a / i+0 DUDEK MurtM.wwMhdillbGuW� t4EWbww e,.w,wonwaaaata�artww. IPes"Ity tllo ( a,bpapoil C*MMr1*r a 1 iYr✓ _- . Benzene Concentration (pglkg) • <10 and non -Meted • 10.100 • 100.1,000 0 1.0oo- 10,000 Benzene Concentrations in soil * samples co0ecled 7=010.7JIOQO10 -- Conlours Concentrations IM D -1.000 1.000.1 MOOD Benzene Concentrations in soil 0 -3ft. 668 ,� V11-11841 VP-4194 \ VP-04 -33/4 - � Benzene Concentration fpglkg) 0 clo and non-dated 10 10-100 0 100-1.000 0 1.000-110.000 Benzene Concentration In soll Contours Concentrations DUDEK Benzerm Concentrations in sail 3.1 -M. BGS we j u•s,igleA' S V-6 . U . ka.S 0-1-YM f tu SMC MAY na as C41mS t V., 3 44 HP-1 I—G..ndwAu fulondming Well 0 410 *1 norl-deted 0 10.10,000 dropunch Locallohl; 0 00 or mon•doind 1111 10.1,000 • Apprmffmte Contours 5 - IF MO Screen and Hytimpunch Cormum 6 - 30' WWI Screen Contours • V - W Well Screen Apprtmirrele Contours Pricentration 010-100 IN 100.1,000 1000.10,01M Hp- 0 i2. e 40, .79 6 4 • s. we. Ytf ON. -MMMA �W QxWm; m, P4 -A :131-M-11 0 5 4C2!! I .O EN "I 9 r 30144, cmf&,WA;CA I 1) U D NoW, Ffgure presents dots evadable to OWIX 30 of ZMIO. caged to re,"mon upon receipt of ad"W data, dEK Hydropunch and Groundwater Monitoring Well Locations with Benzene Concentration jpg4) J s HP-5 f � HP-1 t-Cl 00 rxa,n Groundwater Monitoring Well ■ <50 ■ 10-100 ® 100.1,000 1 101000- 100,000 Hydropunch Locations 0 410 br non -detect • 100-1.0oo 0 1.000. 10.000 • 10,0110.400.000 - - 5'- 15' Weil Screen and Hydropunch Approxnete Contours • S' • 30' Well Screen Contours • • • • 5'- 39 Well Screen Approximate Contours Concentraflon S i k / // o / �N 1 461QNIeen12rape , #� dH.Oaneon•Brd DUD K rnwe Fy1Hr pMnls due ewlledeb DWIN ae of 7122)10,WA*ed to 10"On upon mill of rdd,lorw des IFGSW*RY logo I Bddaoport Commun" d Lip; swe VP41 DMY , >rPao�� ` Soil Vapor Sample Locations Concentration 1� • <10 and non- ted • 10 -100 0 100 -1,000 0 1,000- 10,000 0 10,000- 100,000 • 100,000- 1,000,000 - - - Contours Concentration = 10.100 so 100-1.000 9W, -,"I.000-10.000 10,000-100,000 100,000 - 1,000,000 Sample ponis wah IDs beginning with SV were collected at 113" SGS. w a: Sample points with IDs beginning with ;-4 VP were collected at Y BGS Sub-slab !m samples are denbiled by address. Note that sub -fib sample results wire not contoured, /l oniuuae. ` t �v `rte Soil Vapor Concentrations - .Benzene (pg/mS) �r Y' i VP.0' .. �VP40 , t 1 ,l Y'� J > 0-,r }u„ vP-GI PrO —. \��\�f.. ,J ,w L f Soil Vapor Sample Locations Concentrations al 410 and non-detect. 40 IG-100 b 100 -1,000 O 1,000. 10,000 0 10,000-100,000 i 100,000- 1,000,000+ Concentration 10-100 100-1,000 1.00010.000 10,000- 100,000 100,000. 1,000,000 Sample points with IM begmning with SV were collected at I r BGS Sample points with IDs beginning vath VP were collected at x BGS. Sub-slab samples are identified by address Note that sub-Slab sample results were not contatuad. Soil Vapor Concentratlom = B6nzene (N 3B} de t VP40 !� a 30 w D U D E K MO1 m mromo upon racNpl or addIdordl dot& FEBRUARY 2010 &idgepod Comm rdy �r Y' i VP.0' .. �VP40 , t 1 ,l Y'� J > 0-,r }u„ vP-GI PrO —. \��\�f.. ,J ,w L f Soil Vapor Sample Locations Concentrations al 410 and non-detect. 40 IG-100 b 100 -1,000 O 1,000. 10,000 0 10,000-100,000 i 100,000- 1,000,000+ Concentration 10-100 100-1,000 1.00010.000 10,000- 100,000 100,000. 1,000,000 Sample points with IM begmning with SV were collected at I r BGS Sample points with IDs beginning vath VP were collected at x BGS. Sub-slab samples are identified by address Note that sub-Slab sample results were not contatuad. Soil Vapor Concentratlom = B6nzene (N 3B} Tablailir Valuation of Rpmedial Allematives AACO Facility 08066 bolueo6k—,,, Alternative ?= F(ill Sh MoVistion Od no Aftem W2;-Alr�p i� arid OMM 11ilterhallive3�11a4b C -I 9m1coI0xQr*PW- w1*11 Tte=ff b4-OwU61D ass Extraddon and A "diriterii, i: ii 014is ,�Irigqnd J60419 and O"is M11"i PK1i*E t7 ,, I Doswipt[on of SVE will be Used to address 00-silb Soil vapors SVE will be used to address on- and off-site soil vapors SVE will be used to address on- and off-site Boil YopOrS SVE will be used to address off -site iitoil vapors and Alternative and romeallate the off -site ursalutated zone, M. and Yernediste the on- and off-aft unsaturated zone Air and ismaidote the on -and off-site unsaturated zone remediste the off-sits unsaturated zone Dual-phase sde excavation will be used to directly remove the •sparging (AS) will be utilized to terriedrate the on4le in-situ chemical oxidation will be used to romediete the eidracl!66 will be used to remedlots the on-siti 9611 and corsaimihated soil td a depth of appruxiinately 10 "pacted groundwater AS will remove cksootiraid on•%ft groun[Noateir zone groundwater zone to 15 feet bg& contaminants enhance SVE system effectirverim and vtornote bloriftchation 2 Level or All 4 allernsillyeili are equal for this Woluation Ali 4 alternatives are equal for Ihs evolualicin,coterlon. All 4 alternatives are equal lot this evaluation criterion. All 4 alternatives mie equal r ,It fo thisevalustionRillied n PfivIection of criterion Human Health, the Frivironment, and Beneficial Uses U'l Ground and Surface Waters I Reduction of All 4 alletnefives are equal tot this evaluahnn AN 4 alternatives bte equal lot this Mivatlon criterion A114 aftemAes are equal far this evaluation ctilerion All 4 alternatives are equal for the evaluation criterion H ocarbons criterion, of 4 E� Rank v 4 Rank u 2 Rank a I Rank A 3 Implementiatio Very difficult to implemert due to station demo, Relatively easy to,irriplemerti; Easiest to implement' Relatively easy to implement n and permitting, shoring logistics large number or OMrstion trucks etc 5 cost Ronk #: 4 Rank - 2 Rank -1 Rank ='3 Effectiveness $3,0313,000 to $5 390,00 $832 500 IQ $11,052,51X) $11151,M0 to $1,713,500 S11.24,500 toS2,237,500 6 compliance This altetriative can be implemented within This alternative can be irriplartionled within regulatory This aftc-native can be implemented within regulatory This afternalNe can be implemented within regulatory with regulatory guldelinsi; guidelines guidelines guidelines, Regulatory •Guidebries I Short Term Rork =1 Rankal Rank z 2, Rank a 4 Effectiveness This attetriatiVe I woula addiess, aft conlaminaft 7Kr; alternative would address sle-coritapnods line the fastest • slowest P, Long Term All 4 alternatives are squat for this evaluation AM 4949MRIver- are equal for this evaluation entetion Al 4 afternallves are equal for this evaluation criterion, All 4 alternatives are equal for this evaluation criterion Effectiveness criterion 9' Impacts to Pat* = 4 Rank = 2 Rank =1 Rank: 3 Community Significant commurigy Impacts dud to noise dust, No significant impacts except r6r•trilhor disruptions during No significant impacts except for minor disruptions No significant irnpi* except lot minor dmtijpijbns during VOC vapom traffi r, businea disruptions ffst" installation arg removal tem installation and removal Mom Installation inil removal —0 _EnvmnmmntaI Rank a 4 Rank -- 2 a" Rank * 3 Impacts Adverse impacts to 60'mmunity Include noise Only mini environmental ftactiii due to SVC iystirfi brily minor enylioftmental impacts due 10 SVE systd4i Only min6i onvirionmantal impicts due to SVE and UPE traffic dust va b ration operation system operation •10 —Impacts on . No significant impacts on water conservation No significant Impacts on water conservation No significant impacts on water consefolton No significant impacts on water conservation Water Conservation Table 13 Cost Estimate for Altemative 1 - On -Site Excavation and Off -Site SVE ARCO Service Station No. 6066 Table 13 Remedial Excavatton/Backfill Contractor ($35 /cubic yard) $420,000• $630,000 Contaminated Sod Trucking and Disposal Temporary Relocation of Utilities Lower Estimate Upper Estimate On -Site Excavation Work Plans and Permitting $20,000 $30,000 Cal Coastal Commtsion Exc'Fees $100,000 $200,000 Groundwater Monitoring Well Removal $20,000 $20,000 (11 Wells) Remedial Excavatton/Backfill Contractor ($35 /cubic yard) $420,000• $630,000 Contaminated Sod Trucking and Disposal Temporary Relocation of Utilities $50,000 $100,000 within Excavation Limits Loss of Business Payments to Adjacent Payments $50,000 $80,000 ($10,000 /mo.) Off -Site Laboratory Analysis $50,000 $75,000 ($100/sample• -20 cubic yards) On -She Lboratory Analysis $250,000 $500,000 ($2,500 /day) Groundwater Dewatering, Treatment and POTW Discharge $250,000 $500,000 (if allowed) GW Monitoring Well Re- Installation /7 %All $20,000 $20,000 Sub= Operation of Existina Off -Site SVE Svstem O&M Labor, Utilities, Lab. Fees, Reporting, Expenses $240,000 1$600,000 ($10,000 /mo) OW Monitorina and Reportina Costs OuarterlyGauging, Sampling, Analysis, Reporting, Fcpenses $80,000 ,$240,000 (15 Wells, $10,000 /qtr) , SVE System Decommissioning and Well Abandonment $20b,000 $400,000 Total Cost Range 93.036.000 $5,360,000 Table 14 Cost Estimate for Alternative 2 - On -Site AS /SVE and Off -Site SVE ARCO Service Station No. 6066 Lower Estimate Upper Estimate Install On-Site AS /SVE System. Pilot Testing and Reporting $10 000 $15,000 On -Site AS /SVE System Design and Permitting $10,000 $20,000 Cal. Coastal Comm. Wells Capital Equipment (Air Compressor) $15,000 $30,000 Remediation Installation Contractor (Existing SVE Cmpd and System Stay in Place) $100,000 $175,000 SCAQMD Rule 1166 Monitoring $7,500 $12,500 .Contaminated, Soil Transport and Disposal ($55/tor)) $10,000 $1,5,000 Project Management and Reporting $20.000 $40.000 Sub- Oberatiorr of Existing Off -Site SVE System and On -Site AS /SVE System O &M Labor, Utilities, Lab. Fees, Reporting, Expenses $300,000 $900,000 ($12,500/mo) GW Monitoring and Reporting Costs Quarterly Gauging, Sampling, Analysis, Reporting, Expenses $120,Obd $280,000' (15 Wells, $1.0,000 /qtr) SVE System Decommissioning .,and Well Abandonment $200,000 $400,000 Total Cost $832,600 $1,962,600 Table. 15 Cost Estimate-for Alternative 3 - On -Site ISCO and On- and Off -Site SVE ARCO Service Station No. 6086 Lower Estimate Upper Estimate Install On -Site SVE System Pilot Testing and Reporting $5,000 $5,000 On -Site SVE System Design and Permitting $7,500 $1,000 Cal - Coastal Comm Fees $1'0,000 $20,000 Install On -Site SVE Wells $10,000 $15,000 (8. SVE Wells) Remediation Installation Contractor (Existing SVE Cmpd and System Stay in Place). 150,000 $75 „000 SCAQMD Rule 1166 Monitorina $5,000 $7,500 Contaminated Soil, Transport and Disposal 'd.— $10,000 $15,000 Sub - Total: $112,500 $173,500• Operation of Existing Off -Site SVE System and On -Site SVE System ,O&M Labor,, Utilities, Lab. Fees, Reporting, Expenses $240,000 $600,900 ($10.000 /mo) Perform On -Site ISCO Pilot Testing and Reporting $30,0,00 $50,000 Work Plans and Permitting $10,bb0 $20,000 Install Temporary ISCO Wells Using Dlrect Push Rig, $25,000 $40,000 (29.One -Inch PVC Wells to 15 ft bgs) ISCO'Contractor and Chemicals .$100.000 $150.000 Sub - Total: $185,000 $300,000. GW. Monitorina and Reporting Costs Quarterly Gauging, Sampling, Analysis, Reporting, Expenses $120,000 $240,000 (15 Wells, $10,000 /qtr) SVE System Decommissioning and Well Abandonment $200,000 $400,000 Total Cost 1867,600 $1 713 500 Table 16 Cost Estimate for Alternative 4 - On -Site DPE and Off -Site SVE ARCO Service Statio ri. N6.130813 Lower Estimate Upper Estimate Install On -Site AS /SVE System Pilot Testing and Reporting $10,000 $15,000 On -Site AS /SVE System Design and Permitting $10,000 $20,000 Cal Coastal Comm. Fees $10,000 $20,000 Install On -Site DPE Wells (12 DPE Wells) $25,000 $40,000' Capital Equipment (Air Compressor, Pumps, GW Treatment Skid, Carbon Vessels) $100,000 $150,000 Remediation Installatiori.Contractor tExisting SVE Cmpd and System Stay in Place) $150,000, $-2-00,000 _SCAQMD Rule 1166 Monitoring $7 500 $12,500 Contaminated Sod Transport and Disposal ($55 /ton) $5,000 $10;000 Project Management and Reporting $5,000 '$10,000 Sub - Total'. 5322500 sa77_r%nn Operation of Existing Off -Site SVE System and On- Site AS1SVE• System O &M Labor, Utilities, Lab. Fees, Carbon Changeouts, Reporting, Expenses $15.000 /mo $540,000 $1,080,000 GW Monitorina and Reaortina Costs Quarterly Gauging, Sampling, Anal"is, Reporting, Expenses $160,000 $280,000• (15 Wells, $10,000 /qtr) SVE System Decommissioning and•Well Abandonment $200,000 $400,000 Total Cost $1,222.600 $2 237 500