SITE INFORMATION AND CORRESPONDENCE FILE 2

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California Tank Lines, Inc. Page 3 3105 South EI Dorado Street August 17, 2011 Stockton, California 95206 Based on the high petroleum hydrocarbon concentrations detected in groundwater from MW-4 at the California Tank Line site, and MW-7 and MW-1 at the Pacific Pride facility, one would expect to find high contaminant concentrations in groundwater collected between these impacted areas if the southern site is the source of contaminants impacting MW-4 on the subject site; however, this is not the case. Based on this review, it does not appear that the petroleum hydrocarbon contamination detected in groundwater from MW-4 came from the Pacific Pride facility. If your consulting firm can demonstrate that the petroleum hydrocarbon contaminants detected near MW-4 are not related to the former USTs on your site, the EHD will refer the case to the Spills, Leaks, Investigations, and Cleanups (SLIC) program of the California Regional Water Quality Control Board Central Valley Region. Taber compared doing no remedial action at this site to several active remedial methods: pump and treat (groundwater extraction); dual phase extraction; air sparging/in-situ chemical oxidation; free product removal by bailing; and monitored natural attenuation (MNA). Taber concluded that free product removal by bailing groundwater from MW-2 is the best remedial method to remove petroleum hydrocarbon contamination in the area of the former waste oil tanks; and MNA is the recommended remedial method to remove contaminants of concern in the area of MW-4. Taber also recommends that an additional monitoring well (MW-5), screened between 17 and 37 feet bsg, be installed adjacent to MW-2. Since depth-to-groundwater measurements taken in February 2011 were approximately 25 feet bsg, this new well may enhance the removal of free product that is currently above MW-2's screened interval of 30 to 50 feet bsg. Taber proposes to continuously log the borehole to total depth of approximately 40 feet bsg. Although Taber does not illustrate the proposed location of MW-5 in any of the Figures presented in the CAPFS, the EHD approves the work plan for installing MW-5 adjacent to MW-2. Submit a boring/well permit application permit/inspection fee to the EHD and complete the well installation by 01 November 2011. (Please note that the EHD's hourly fee has increased from $122 to $125 per hour.) The EHD also approves the pilot test using disposable bailers to bail free product from both MW-2 and newly-installed MW-5. Taber proposes to remove the free product daily for a period of one week or until the free product recovery rate has stabilized. If necessary, Taber proposes to use a skimmer if hand bailing fails to keep up with the recharge. Taber proposes to use existing data and collect additional data to input into the Bioscreen model to: • Predict the future extent and concentration of the dissolved-phase contaminant plume by modeling the effects of advection, dispersion, sorption, and biodegradation; • Assess the possible risk to potential down-gradient receptors; and • Provide technical support for selection of the MNA option as the best remedial alternative." The EHD approves the collection of the MNA parameters as proposed by Taber. The data will be used in the Bioscreen model to determine: • Natural degradation rates; • Fate and transport of dissolved degraded fuel hydrocarbons; and • Potential risk to human health and the environment.