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HomeMy WebLinkAboutCC AG PKT 2010-07-12#BBAGENDA STAFF REPORT DATE: July 12, 2010 TO: Honorable Mayor and City Council THRU: David Carmany, City Manager FROM: Sean Crumby P.E., Director of Public Works SUBJECT: JUNE 19, 2010 ARCO CORRECTIVE ACTION PLAN SUMMARY OF REQUEST: Authorize the City Manager to sign the attached letter commenting on the Arco Corrective Action Plan (CAP), which, among other recommendations, requests that Orange County Health Care Agency ( OCHCA) require implementation of ARCO's remedial alternative no. 1 (on -site soil excavation). BACKGROUND: In early 2009, the Orange County Health Care Agency ( OCHCA) informed the City that Arco would be installing a temporary soil vapor extraction system. The work was required due to high levels of benzene (a known human carcinogen that is found in gasoline products) detected in the Bridgeport area. Since November 2009, city staff has been working closely with OCHCA, City Attorney's Office, a specially retained environmental consultant, Dudek, and Arco representatives and the community to evaluate the health and safety risk caused by the soil, groundwater and soil vapor contamination. Under the direction of OCHCA, as an immediate remediation, Arco has collected soil samples underneath several 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 gasoline station at 490 Pacific Coast Highway. In February 2010, Arco submitted a "Preliminary Corrective Action Plan." On March 22, 2010, the City Council authorized the City Manager to send a letter stating the City's recommendations regarding the Preliminary CAP. That letter was dated and sent on March 24, 2010. OCHCA reviewed numerous comments on Arco's Preliminary Corrective Action Plan and ordered Arco to submit a revised Corrective Action Plan by June 19, 2010. Arco provided a copy of the revised Corrective Action Plan to city staff on June 21, 2010. Arco's revised Agenda Item BB Page 2 Corrective Action Plan addresses comments from the Preliminary Corrective Action Plan. On June 23, 2010, OCHCA notified the public that the comment period had commenced and that the deadline for receipt of public comments by the Agency is July 23, 2010. See attached letter. ARCO's revised Corrective Action Plan outlines seven basic topics: • Site Background (geological and groundwater conditions) • Review of historical investigations (how this all started) ® Assessment of extent of contamination (in soil, soil vapor, and groundwater) • Site model • Proposed clean -up levels for site and off -site (Bridgeport community) • Review of alternative remediation methods: i. Source area excavation with supplemental electrical resistance heating remediation (ERH) and off -site soil vapor extraction ii. On -site remediation by ERH and off -site soil vapor extraction iii. Dual -phase extraction for on -site and off -site soil vapor extraction • Summary and proposed implementation plan for ERH remediation system. In the cover letter to the CAP prepared by ARCO personnel (Mr. Chris Winsor), ARCO indicated that although ARCO preferred ERH, the company is prepared to implement either ERH or Alternative 1 (excavation of on -site contamination with supplementary ERH). The City's environmental engineering consultant and Environmental Quality Control Board, and the Bridgeport Community Technical Advisory Committee, have reviewed and commented on Arco's Corrective Action Plan. There will be ongoing meetings with ARCO /BP representatives to discuss the City's desire for "Dig and Haul ". After careful review, the following are a summary of comments to be submitted to OCHCA: 1) The most reliable and assured remedial alternative is an excavation of the source area ( "dig- and - haul ") approach. This is essentially Alternative No. 1 in the CAP. But, the scope of the excavation as described in the current CAP appears to be too limited and should be expanded to obtain cleanup standards that are fully protective of the Bridgeport community. 2) (2) ARCO's principal remedial alternative (Alternative 2), ERH, is a system that could be technically implemented, but still has some uncertainties in its potential application to this specific site. Given the length of time that remediation at this site has already taken, the City and residents urge that OCHCA not accept a remedy that is still in the "yet to be proven" status, at least as the specific soil conditions at this station. Page 3 3) ARCO's description of its short-term and long -term cleanup goals for soil and groundwater beneath the station (and in the off -site Bridgeport community) is both imprecise and uncertain. OCHCA should insist that the scope of the remediation obtain clear and measurable cleanup goals. FINANCIAL IMPACT: There is no financial impact. RECOMMENDATION: It is recommended that the City Council authorize the City Manager to execute the attached comment letter to be submitted to OCHCA concerning the ARCO Corrective Action Plan (CAP). SUBMITTED BY: Sean Crumby P.E. Director of Public Works NOTED AND APPROVED: David Carma y, City Manager Prepared by: Michael Ho, City Engineer Attachments: A. City Comments on Revised ARCO CAP prepared by DUDEK, dated July 7, 2010 B. City's comment letter to Mr. Martinez of OCHCA dated July 19, 2010 C. Copy of OCHCA June 23, 2010 letter requested comments on Revised ARCO CAP COMMENTS ON THE CORRECTIVE ACTION PLAN FOR ARCO SERVICE STATION NO. 6066 in SEAL BEACH Prepared for: City of Seat Beach 211 Eight Street Seal Beach, CA 90740 Contact Michael Ho Prepared by: UDEK 605 Third Street Encinitas, California 92024 tetc - ? �- L Peter T. Quinlan Donn L Ma in, PhD Principal Senior Scientist Derek Reed, PE Senior Engineer 7 JULY 2010 COMMENTS ON THE CORRECTIVE ACTION PLAN FOR THE ARCO SERVICE STATION NO. 6066 Dudek reviewed the Corrective Action Plan (CAP) for ARCO Station No. 6066 prepared by Stantec and dated June 19, 2010. The comments on the CAP presented below were prepared at the request of the City of Seal Beach. This review was based on data available at the time of the review. As additional data becomes available, Dudek may change the comments and observations contained in this document. The CAP was prepared to address subsurface gasoline - related contamination associated with the ARCO Station No. 6066 (the site). The CAP rates electrical resistance heating (ERH) as the preferred remedial alternative. The CAP rated on -site source area excavation with supplemental ERH as the second alternative followed by Dual Phase Extraction (DPE). All three alternatives entail continued soil vapor extraction off -site. The following comments are intended to assist in identifying additional data needs so that the effectiveness and costs of the alternatives -can be evaluated on a more equitable and realistic basis in the final CAP. The comments are grouped according to the following topics for . convenience: Comments- on proposed cleanup levels and goals (Comments 1 -4); comments on the technically preferred remedy, ERH, (Comments 5 -10); and comments on other portions of the CAP including its discussion of the extent of hydrocarbons in soil, soil vapors, and groundwater (Comments 1 I -14). Comment I Cover Letter The cover letter states: The remedial alternatives included in the CAP were evaluated against selection criteria identified by OCHCA and the Santa Ana Regional Water Quality Control Board in a letter to OCHCA dated April 15, 2010. These criteria include: • Remedial Effectiveness • Remedy Duration • Cost Effectiveness fiectiveness However the Regional Water Quality Control Board wrote: "Although the subsurface contamination may pose a threat to the environment and 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUDYW S i beneficial use of this Basin, the primary driver for this cleanup is the potential human health vapor risk to adjacent residents and commercial business occupants, posed by contamination emanating from soil and /or groundwater as a result of discharges from the ARCO service station. The cost of a given cleanup strategy can not be considered the primary or most heavily - weighted criteria for selection of a remedial technology at a site with this magnitude of contamination and potential threat. in fact, significant additional weight must be given to the strategy that provides the most immediate and certain resolution to this matter." The OCHCA wrote: "Although cost effectiveness is one factor in evaluating the CAP of any underground storage tank (UST) cleanup case, the ongoing potential public health impacts and the disruption to the community coupled with the age of this case, requires a revised CAP'the provides the most immediate, effective, and certain final remedy for this site." Both agencies stressed immediacy and certainty. The goals set in the cover letter replaced certainty with effectiveness. There are site - specific factors which make the effectiveness of ERH less than certain. Remediation by ERH at the ARCO Station 6066 may be successful in six months, but that is not certain without pilot testing. In contrast, there is much greater certainty regarding the effectiveness and costs of the excavation alternative (Alternative No. 1). Comment 2 Section 6.1 — Soil Cleanup Levels, Page 34 The CAP proposes setting short term cleanup soil goals based on USEPA Region IX Regional Screening Levels (formerly known as preliminary remediation goals (PRGs). Longer term goals would be determined based upon groundwater and soil vapor goals. However, USEPA Region IX has stated that the PRGs for benzene should not be applied in California; but rather, the California OEHHA risk factors should be applied (EPA, Region 4, webpage entitled "Regional Screening Levels, discussion of "Toxicity Hierarchy" ( "It should be noted that Cal /EPA's Office of Environmental Health Hazards Assessment ( OEHHA) also derives peer- reviewed toxicity values that should be used in California, particularly if they are more stringent than EPA's toxicity values. ") The soil cleanup level should be determined on the basis of potential impacts to human health (using the Cal -EPA Unit Risk Factor (URF)) and potential impacts to groundwater. The proposed soil cleanup goal presented in the CAP is the EPA Region IX Regional Screening Level (RSL). The residential soil RSL is 1,100 ug/kg. The industrial soil RSL is 5,400 ug /kg. The RSLs are not based on the Cal -EPA URF for benzene and would result in estimated increased cancer risks of on the order of I x 10` to I x 10 -3 when using the DTSC Herd modification of the Johnson and Ettinger model, which is designed to evaluate vapor intrusion. 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUDTK The CAP indicates that a leachability factor of 500 can be derived. Further, the CAP suggests that this leachability factor translates to a site - specific "Soil Screening Level" (SSL) for benzene of 0.5 milligrams per kilogram (mglkg), which would adequately protect groundwater. While the report notes that the current data set is insufficient to determine a site - specific SSL, there were two other soil samples that produced leachate with benzene concentrations above the analytical detection limit (i.e., SB -32 -8 and B- 35 -5). The leachability factor for the former was 1.6, which would substantially lower the site - specific SSL for benzene. Moreover, numerous soil samples collected from this site contain benzene levels in excess of the 10 mglkg reported for B -33 -8 (for which no leaching tests were conducted). Finally, a concentration of 0.5 mg /kg in soil may not be protective of human health (as a result of benzene partitioning into soil vapor beneath occupied structures), even if it were protective of groundwater quality. In addition to the range of results obtained from the leachability study, the leaching test (EPA Method 1 312) has technical limitations. The leaching test used to generate Table 16 in the CAP employs an 18 -hour agitation of soil with a volume of water equal to 20 times the weight of the sample; however, the results of this leachability test may produce lower leached concentrations than those derived from leaching tests that expose the soil samples to water for a period of weeks or months, instead of hours. In this site, a longer leachability test would appear to be appropriate given that the soil contaminating groundwater beneath this site has probably been inundated for years or decades (considering the estimated release dates) as a result of seasonal or episodic water level changes. Thus, the leachability factor of 500 may understate the tendency for actual leaching at this site, and thereby result in a cleanup goal for benzene in soils that is too high. Although not entirely clear, it appears that the CAP ultimately proposes to use EPA Regional Screening Levels as cleanup goals, at least in the short term. That in itself is a misapplication of the Regional Screening Levels (EPA Region 9), which states that: "It should be emphasized that SLs are not cleanup standards." (EPA Region 9, "Users Guide" to Regional Screening Levels, Introduction). Moreover, the CAP does not provide to the Agency or to the public a defined set of long -term soil cleanup goals. Instead, the CAP simply suggests that "as additional data.. . is collected, site - specific SSLs can be developed..." Comment 3 Section 6.2 — Groundwater Cleanup Levels, Pages 41 -42 The CAP proposes a short term groundwater cleanup goal based on the RWQCB's low risk threshold values for aquifers with non - drinking water beneficial use designations. This low risk threshold value can be applied only where it can be shown that the contamination does not present a significant risk to human health. The CAP suggests that in the long term remediation by natural attenuation will ultimately achieve MCLs in groundwater, but does not specify exactly when this long term cleanup goal will be achieved. The CAP suggests that "20 years" might be a reasonable time to reach that long term goal. 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUDTX The CAP's short term goal of 250 ug /I for benzene in groundwater appears to leave a level that could still pose a human health risk. The DTSC HERD vapor intrusion risk model indicates that a groundwater concentration of 250 ug/I of benzene at a depth of 5 feet yields an estimated excess cancer risk of 5.9E -04, assuming the properties of a sandy loam soil. Human health risk should guide the selection of cleanup goals, and the presence of soil vapor concentrations beneath the streets and houses in the Bridgeport community demonstrates that there is a potential human health risk. A groundwater concentration of 250 micrograms per liter (ug/l) of benzene yields a theoretical vapor concentration of approximately 53,900 micrograms per cubic meter (ug /m3) according to Henry's Law. This vapor concentration is far in excess of the residential site - specific cancer -based screening level for benzene of 40.3 ug/m3 established by McDaniel Lambert for the site. Comment 4 Section 6.3 — Soil Vapor Cleanup Levels, Page 42 The CAP specifies that the soil vapor cleanup level is the residential site - specific cancer -based screening level for benzene of 40.3 ug/m3 at 18 inches below land surface and deeper as established by McDaniel Lambert for the site and subsequently reviewed by OEHHA. This cleanup goal is appropriate for offsite residential areas. The proposed soil and groundwater cleanup goals appear insufficient to achieve this soil vapor cleanup goal. The CAP suggests that homes with excess cancer risks (as determined by the analysis of sub - slab vapor samples) did not correlate with proximity to the ARCO site. A review of benzene concentrations detected in vapor probes at 2- and 4 -foot depths indicates that there is a clear pattern of higher concentrations being located closer to the ARCO station. Vapor concentrations of benzene greater than 1,000 ug 1m3 are located within 80 feet of the station. Vapor concentrations of benzene greater than 100 ug /m3 are located within 200 feet of the station. But beyond this pattern, ARCO has concluded that there is vapor migration along preferential pathways in utility trenches. If there is anisotropic migration of contaminants along preferential pathways, the relevant factor would not be not proximity to the ARCO site, but proximity to preferential pathways that have intercepted contaminants. If the mode of transport is strictly vapor - phase, then preferential pathways could even intercept contaminants located hydraulically downgradient of the homes. Comment S Section 7. 1. The report suggests that Remediation by Natural Attenuation (RNA) will be used as "a polishing technology to reach MCLs in groundwater" after the main source area has been treated. At very low aqueous concentrations, benzene biodegradation by microorganisms may not be significant because the benzene no longer serves as an adequate carbon source. As such, it is likely that most of the RNA polishing will consist of dispersion and dilution. 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUDEK iv The report lists "evidence of ongoing RNA at the site" in various categories. Redox indicators such as BOD, COD, dissolved oxygen, and ferrous iron do indicate that highly reducing conditions and abundant organic substrates are present onsite. Based on the sulfate and methane concentrations, sulfate - reduction and methanogenesis are probably the predominant onsite biodegradation pathways at B -4 and B -17. By contrast, more oxidative and kinetically faster pathways such as iron - reduction (and even nitrate - reduction at a few wells) probably prevail at offsite locations. Based on the February 2010 concentrations of dissolved carbon dioxide, which is a product of hydrocarbon conversion for all common metabolic pathways (including acetotrophic methanogenesis), biodegradation may currently play a larger role in offsite RNA than onsite RNA. Five of the six highest CO concentrations (including the highest) were measured in offsite wells, suggesting that non - biological processes are likely contributing to the onsite restraint of the plume. Non - biological processes may include dilution, sorption, volatilization, or lower groundwater flow velocities than estimated. The hypothesis that biodegradation is primarily responsible for constraining the areal extent of fuel hydrocarbons is further challenged by the relatively small oxygenate (i.e., MTBE and TBA) plumes, because these two compounds are more refractory and water - soluble than are the hydrocarbons. The CAP also cites the apparent stability of the groundwater plume as evidence of ongoing RNA. The CAP presents a calculation of potential groundwater migration that predicts that the leading edge of the plume should be 300 feet from the site after 20f years and states that the plume has not migrated that far. However, the CAP uses assumed values for hydraulic conductivity and effective porosity. The report does not mention what values of bulk density and fraction of organic carbon were used in calculating retardation of hydrocarbons in the aquifer or whether this was factored in. The calculation might inspire greater confidence in the conclusion that results from it if site specific values for hydraulic conductivity derived from the recent aquifer test of a 20 -foot deep well was used. Furthermore, the CAP acknowledges that concern has been raised that the existing long screen monitor wells create the potential for dilution of petroleum hydrocarbon concentrations thus calling into question the degree to which the extent of benzene has been defined to the west and southwest (Section 4.4.2). Comparing the theoretical migration of groundwater based on assumed hydraulic properties to the extent of groundwater contamination based on potentially misleading groundwater concentrations is not convincing evidence of effective RNA at the site. Comment 6 Section 7.2.1 Excavation The lack of unambiguous soil and groundwater cleanup goals (short or long term) makes it difficult to evaluate the proposed extent of remediation. The CAP presents a proposed excavation foot print with a I -to- I slope that does not incorporate the areal extent of soil containing benzene at concentrations of 0.5 mg /kg, The excavation does not extend to 6551 -1 Comments on CAP for ARCO #6606 2010 v locations on -site where observed benzene concentrations in soil exceed 5.4 mg /kg or off-'site where concentrations exceeded 1.1 mg/kg. Notably, the excavation does not extend to SB -1, SB -7 (where 15 mg/kg of benzene was detected at 5 feet), SB -8 (2.9 mg/kg), SB -16 (8.6 mg /kg), SB -17 (1.6 mg/kg), SB -19 (14 mg /kg), and SB -23. Nor does the excavation extend beyond the block wall to the vicinity of SV -5 and SV -7, which originally contained benzene concentrations of 1.5 and 1.7 mg /kg and where there has apparently been some rebound of vapor concentrations while the SVE system has been operating (as indicated by Table 12). The CAP identifies difficulties associated the proposed large open pit excavation, including fugitive VOC vapors, proximity of utilities, and groundwater dewatering. These potential difficulties could be ameliorated if the excavation were conducted in discrete 20- by 40 -foot boxed cells using sheet pilings. Driving sheets to approximately 20 feet while dewatering within the boxed cell from depths of 15 feet or less could decrease the amount of groundwater that would have to be pumped, treated, and discharged. The sheet pilings could also protect utilities while, at the same time, allowing the excavation to more closely approach them by eliminating the I -to- I slopes. The smaller discrete cells would also lend themselves to covering the active excavation and managing vapor emissions. Comment 7 Section 7.2.2. The report suggests that increase air flow through the subsurface resulting from SVE will stimulate biodegradation of the contaminants. Whereas the subsurface air flow will likely result in conditions providing more oxygen along the dominant airflow pathways, the ability of SVE to "stimulate" biodegradation will depend on a number of unrelated physical, chemical, and biological factors. Given the heterogeneity of soils underlying this neighborhood (including high - permeability conduits), it is unlikely that "two preliminary radius of influence tests" are adequate to project the kind of SVE coverage displayed on Figure 36. Comment 8 Section 7.2.3. The CAP indicates that ERH can be safely performed adjacent to or under buildings and public right -of -ways with a 99% or greater reduction in contaminant concentrations in both soil and groundwater. There a number of questions related to implementing ERH at this site, including: Are all subsurface utilities and deep- rooted plants (trees) unaffected by ERH? The proposed treatment temperature is approximately 100 degrees C. There may be temperature - related issues to subsurface utilities within the treatment area. Water lines are reportedly Schedule 80 PVC. The typical maximum service temperature of Schedule 80 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUDEK vi PVC pipe is 60 degrees C. A Verizon fiber optic line is located within the treatment area. The typical maximum operating temperature for fiber optic cable is 50 -80 degrees C. o What exactly does a contractor's ERH performance guarantee provide —and to whom? v Do the relatively high TDS levels measured at this site provide enough electrical resistance (as soil pore water) to permit adequate heating of the subsurface? A presentation by the Navy Facilities Engineering Command (NAVFAC) at RITS 2007 on ERH listed the "presence of non - volatile solutes, such as chlorides, sulfate, calcium, carbonate, etc." as factors making it more difficult to achieve boiling point temperatures. o Are the local soils optimal for ERH, which is reportedly more efficient in sands than in silts or clays and more applicable to source ( offsite) areas than to peripheral (offsite) locations? Again the NAVFAC presentation indicated that design temperatures were more successfully achieved at all depths in sandy soil. ERH will initiate a variety of physical and chemical processes that occur simultaneously — depending on how quickly the temperature rises. Can the resulting pressures and chemical products be adequately contained by the recovery and treatment systems as currently designed? These systems will have to deal with peak contaminant loads, whether or not subsurface temperatures are monitored and regulated on a real -time basis. Whereas elevated temperatures on the periphery of the ERH treatment zone may increase the kinetics of biodegradation processes, extreme temperatures within the active treatment zone will kill any non - thermophilic soil microorganisms. How long is the typical recovery period for soil microflora? As noted in the report, many of offsite areas within the neighborhood contain elevated levels of high molecular weight organics (i.e., ORO), which may interfere with or complicate the ERH treatment processes. How will this affect the performance of offsite remediation using ERH? Comment 4 Section 7.3. The first paragraph in this section indicates that the SVE system will operate until the cleanup goals are attained at key vapor monitoring points or until it is demonstrated that the offsite system is no longer necessary. Where are the key monitoring points and how have they been (or will they be) selected? Other than achieving the cleanup goals, what exactly will "demonstrate" that the operation of the SVE system is no longer necessary? 6551 -1 July 2010 Comments on CAP for ARCO #6606 DUD V EK vii The report reiterates that all remedial alternatives depend to some extent upon RNA to reduce contamination to background levels after the active remediation phase has addressed the bulk of the contamination. As previously noted, RNA includes physical processes such as dilution, dispersion, and phase partitioning, as well as biodegradation. The degree to which biodegradation is a primary component of the RNA will depend on the active remediation alternative that is implemented and the characteristics of the residual contamination. Comment 10 Sections 7.3.1 and 7.3.2. The report indicates that about 80 °l0 of the temperature monitoring probes and electrodes required for Alternative 2 (ERH) would be required for Alternative I (excavation plus ERH). Considering that a substantial portion of the plume would be excavated and dewatered during the initial phase of Alternative 1, it is not clear why the peripheral and offsite portion of the plume would require almost as many ERH - related probe installations (for temperature sensors and electrodes) as Alternative 2. Comment I I Section 4.3.4. The CAP concedes that the extent of GRO and benzene have "not been defined" to the west and southwest, and indicates that further work in the west and southwest of the service station is in progress. Considering the long history of site investigation and the importance of defining the lateral extent of contamination to the selection of offsite remediation alternatives, this is a critical data gap. Comment 12 Section 4.4.2. The CAP and pertinent figures suggest that the areal extent of fuel- related contaminants in groundwater have not been defined in most cardinal directions, including the intersection of Schooner Way and Galleon Way. Given that water contamination may exist under homes and streets, the options for offsite remediation may be substantially more limited that those for onsite contamination. This data gap raises the question of whether an appropriate offsite remediation alternative be selected at this time. 655 1 -1 Comments on CAP for ARCO #6606 2010 viii Comment 13 Section 4.5.4. The CAP cites a residence where a leaking natural gas line was believed to be the source of methane and benzene contamination in soil vapor or sub -slab samples. Was a detailed analysis of the gas performed and, if so, where are the results? Natural gas has a distinctive fingerprint in terms of both its light hydrocarbon constituents and its various additives. What concentrations of benzene in soil vapor probes or sub -slab samples is the report attributing to natural gas leaks? The last sentence of this section suggests that SVE has been successful in reducing concentrations of hydrocarbon vapors in the vicinity of the service station. Once again, this generalization may be valid for most vapor sampling points; however, it is certainly not true for all. In fact, one of the five wells (VP -10) listed on Table 8 displayed increasing TVH and benzene concentrations after the initial 7 -week operation of the SVE system. Considering the location of VP­ 10 and its proximity to offsite groundwater contamination (or to soil contaminants that are in equilibrium with groundwater), how effective is SVE for vapors emanating from offsite soil or groundwater contamination. Might SVE be applicable only to offsite vapors that have an onsite source? If so, defining the lateral extent of offsite soil and groundwater contamination (particularly beneath residences) is critical to selecting an offsite remediation technology. Comment 14 The CAP provides no data to substantiate the conclusion that "SVE is mitigating potential vapor intrusion risks." For example, have sub -slab vapor concentrations in the homes with a greater than one -in -a- miIlion cancer risk exhibited declining benzene levels that correspond to the operational period of the SVE system? 6551 -1 July 2010 Comments on CAP for ARCO #6606 ix July 19, 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 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 Corrective Action Plan ( "CAP ") submitted by Stantec on behalf of Atlantic Richfield Company ( "ARCO ") dated June 19, 2010. For the reasons stated below and those in the attached comment report of Dudek, the City urges that the Orange County Health Care Agency ( "Agency ") require significant modifications to the CAP. I. CONCERNS ABOUT THE CAP AS PRESENTED A. The CAP Fails to Identify the Appropriate Soil and Groundwater Cleanup Levels 1. Groundwater Cleanup Levels Are Not Clearly Stated and the Suggested Short -Term Level for Benzene is Not Protective of Human Health In Section 6.2 of its CAP, ARCO admits that the appropriate Santa Ana Regional Board Basin Plan 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). Thus, the appropriate groundwater cleanup level should be the applicable state (or federal) Maximum Contaminant Level (MCL). While ARCO agrees with this general observation, and correctly states that the MCL for benzene is 1 µg/L, it then immediately shifts to a different standard for at least "short- term" cleanup of 250 µg/L based upon a set of "Low - Risk" Threshold Values. This "short- term" cleanup goal is unacceptable for the reasons explained in the attached Dudek report, Comments on the Corrective Action Plan for Arco Service Station 6066 —Seal Beach, comments 3. We also note that even the "Low- Risk" 57296 -1131 \ 1243452v l . doc Threshold Value for TBA, another gasoline related compound of concern, is 100 µg/L, and that this level is exceeded at numerous locations on the service station site. ARCO's CAP does not expressly commit to a long -term groundwater cleanup goal, but appears to suggest that a long -term goal might be MCLs achieved only by "remediation by natural attenuation." As explained in the attached Dudek report, there are a number of technical questions concerning the reliance on remediation by natural attenuation at this site, Comment No. 5. The City also incorporates by reference its prior set of comments in its March 24, 2010 letter to the Agency concerning questions about ARCO's reliance on remediation by natural attenuation as stated in ARCO's Preliminary CAP. 2. Appropriate Soil Cleanup Levels In Section 6.1 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. But, as noted by EPA Region 9 itself in its guidance document accompanying its Regional Screening Levels, these levels are not to be used for establishing cleanup goals. (Dudek Report, Comment No. 2). But, ARCO departs from the EPA Regional Screening Levels based upon its characterization of a "Synthetic Precipitation Leaching Procedure ", which ARCO suggests will result in a sit - specific level of .5 mg/kg for benzene. (CAP, Section 6.1 at p. 40). The Dudek Report confirms that this static -type leaching test and the data relied upon are at best incomplete. (Dudek Report, Comment No. 2). Ultimately, ARCO does not commit to a single soil cleanup level, but only suggests that "site- specific SSLs can be developed" in the future. This position of "we'll develop the cleanup goals later over time" is inconsistent with State Water Board regulations that require a CAP to include: "applicable cleanup levels, in accordance with Section (g) of this Section." 23 Cal. Code Regul. §2725 (d)(3). Subsection (g) of Section 2725 further provides that: "The responsible parry shall recommend target cleanup levels for long -term corrective actions to the regulatory agency for concurrence." In this instance, it appears that ARCO has not recommended long -term cleanup soil levels, but only promised to do so in the future. B. Uncertainty as to the Effectiveness of ARCO's Proposed Electric Resistance Heating (ERH) Preferred Alternative The CAP apparently rejects ARCO's preference for In -Situ Chemical Oxidation ( "ISCO ") in favor of a different technology not even mentioned in the Preliminary CAP, Electric Resistance Heating ( "ERH "). Although ERH can be effective in treating below - ground contaminants, it has been principally used on VOCS, not hydrocarbons. As with any in -situ remedial system, there are a number of technical questions about the efficacy of ERH to this specific site. Dudek Report, Comments Nos. 8, 10. The City does not have direct experience with the potential impact of ERH to municipal PVC pipelines, but is concerned that any off -site application of ERH that impacts city and private PVC pipelines could heat those pipelines beyond recommended heat levels. Dudek Report, Comment No. 8. 2 57296 -1131\ 1243452v l . doc C. ARCO's "Evaluation" of the Remedial Alternatives is Seriously Flawed ARCO's CAP rates the ERH proposed remedial alternative highest, with on -site excavation "coming in a close second." 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 time span deemed acceptable to Orange County Health Care Agency, but contends that it "achieves overall soil and groundwater cleanup goals slower ", apparently because it will purportedly "delay the installation and startup of the ERH system." (CAP, Section 7.4, p.61). But, the City believes that the paramount concern of the Bridgeport residents is for the fastest possible cleanup of the on- site sources of contamination that threaten their neighborhood. If this goal (on -site soil and vadose zone contaminant removal) is achieved first, then the highest priority for the City and its residents is achieved. 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. The City respectfully refers the Agency to the analysis in the attached Dudek, Comments on the Corrective Action Plan, which could impact upon the effectiveness of the proposed ERH remedy. (Comment No. 8). This is not to say that under no circumstances could ERH work at 490 Pacific Coast Highway; rather, the Dudek report demonstrates that a number of site - specific subsurface soil chemistry issues need to be evaluated carefully before any selection of ERH 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. The City also does not understand the CAD's preference for ERH based upon alleged regulatory simplicity. At Section 7.4, page 62, the CAP states that a large excavation project will 3 S7296- 1131 \1243452v l .doc require a California Coastal Commission permit "in contrast to ERH." But, the ERH project will require demolition and removal of the existing service station structure. (CAP, Section 8.3). Public Resources Code section 30600(a) requires a Coastal Development Permit for "development." "Development" is defined in PRC Section 30106 as including "... the "discharge or disposal of any dredged material or of any gaseous, liquid, solid, or thermal waste: grading, removing, dredging, mining, or extraction of any materials; ... demolition, or alteration of the size of any structure ...." Thus, ARCO's proposed demolition of the service station structure as part of ERH will in fact require the same type of "time- delaying" California Coastal Permit approval that the excavation remedy will require. II. RECOMMENDATIONS FOR MODIFICATIONS TO THE CAP The City recommends that OCHCA accept the 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 a concentration of benzene in soil that ensures that soil vapor concentrations are less than 40 micrograms per cubic meter in residential areas and 325 micrograms per cubic meter in commercial areas. (2) The CAP be modified to include the most recent data on hydrocarbon contaminants in the soils and groundwater based upon more recent data and also include in depictions of groundwater impacts all available hydropunch data as well. (3) The selected remedy should be Alternative No. 1 (soil excavation, with supplementation from an alternative technology as necessary) and be modified as follows: (a) ARCO should supplement its on -site excavation remedy to include excavation to a depth of up to 10 feet (the exact depth of excavation to be based on the currently available data) in the street and alley areas to the north, west, and southwest of the site where benzene and other gasoline hydrocarbon levels in soil are above clean-up levels. (b) ARCO should include replanting the dead trees along the fence line in the contaminated area south of the site and shrubs to re- establish visual screening of the site from the Bridgeport Community. In addition, the high intensity lighting at the back of the site should be screened or shielded from glaring at the residential community. (c) Excavations and permanent wells or soil sampling locations in Bridgeport community streets must be completed to current City standards for both construction quality and visual appearance. Cease any further pilot study work for air sparging on the grounds that given the site conditions and contaminant distribution, further studies are unlikely to establish a cost - effective remedy at this site; (d) ARCO should use low- emission trucks to haul excavated soils to the appropriate disposal or incineration facility. The Agency should also require training of all truck 4 S7296 -1131 \ 1243452v l .doc drivers as to the proper methods of entering onto station property and properly exiting from Fifth Street to access northbound PCH; (e) ARCO should developing a traffic safety plan that addresses vehicles, bicycles, and pedestrian traffic and includes notifications, routing alternatives, signage; (f) ARCO should 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; (g) ARCO should comply with all City permits for both off -site and on -site remediation work; and (h) ARCO should submit to the Orange County Health Care Agency 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 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 Honeyboume, 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 Cannany City Manager City of Seal Beach Attachments: Dudek, Comments on the Corrective Action Plan for ARCO Service Station No. 6066 in Seal Beach cc: Mr. Larry Honeybourne (OCHCA) Mr. Richard Sanchez (OCHCA) Mr. Osman Taban (OCHCA) Ms.Carole H. Beswick, Chair, Santa Ana Regional Water Quality Control Board Mr. Gerard J. Thiebault, Executive Officer, Santa Ana Regional Water Quality Control Board Mr. K. Williams, Senior Engineer /Geologist, Santa Ana Regional Water Quality Control Board Ms. Valerie Jahn -Bull, Environmental Scientist, Santa Ana Regional Water Quality Control Board Mr. H. Chris Winsor, Regional Environmental Manager (BP /Atlantic Richfield Co.) Mr. Darrell K. Fah, Operation Project Manager (BP /Atlantic Richfield Co.) Mr. John M.W. Moorlach, Supervisor, Second District Orange County 5 S7296-113 1\ 1243452v 1. doc COUNTY OF ORANGE HEALTH CARE AGENCY PUBLIC HEALTH SERVICES ENVIRONMENTAL HEALTH Excellence Service PUBLIC NOTICE Revised Corrective Action Plan, dated June 19, 2010 Posting Date: June 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 amartinez@ochca.com DAVID L. RILEY DIRECTOR DAVID M. SOULELES, MPH DEPUTY AGENCY DIRECTOR RICHARD SANCHEZ, REHS, MPH DIRECTOR ENVIRONMENTAL HEALTH MAILING ADDRESS: 1241 E. DYER RD., #120 SANTA ANA, CA 92705 -5611 TELEPHONE: (714) 433 -6000 FAX (714) 754 -1732 E -MAIL: ehealthRDochca.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 was prepared by the responsible party. After a public comment period, the OCHCA issued a request for a revised CAP. This plan has been submitted to the OCHCA for review and approval prior to its implementation. OCHCA staff is currently reviewing the revised CAP and is accepting comments from the public until July 23, 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 three remedial alternatives described in the plan. The three alternatives described in the preliminary CAP are as follows: 1) Source area excavation with electrical resistance heating and off -site soil vapor extraction; 2) Electrical resistance heating with off -site soil vapor extraction; and, 3) Dual -phase extraction and off -site soil vapor extraction. OCHCA will hold a public meeting in July to discuss and take public comments about the Corrective Action Plan. 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 Environmental Health Records at (714) 433 -6022. The revised CAP can be found at: https -// geotracker .waterboards.ca.gov /esi /uploads /geo_ report/8704722106/TO605900372.PDF, and https: / /geotracker. waterboards. ca. gov /esi/ uploads / geo _report/8015855193/TO605900372. PDF You can find other information about this site at: https: / /geotracker.waterboards .ca.gov /profile_report.asp ?global id= TO605900372.