SITE INFORMATION AND CORRESPONDENCE FILE 2

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MW California Tank Lines, Inc. Page 2 of 3 3105 South EI Dorado Street June 16, 2015 Stockton, California 95206 • Select and preserve continuous core soil samples from pilot boring MW-9 from depth zones of interest for chemical analysis by a California State-certified laboratory; sample selection will be based on field indicators of petroleum hydrocarbon staining or odor, geologic conditions, PID measurements, and professional judgement; ® Select and preserve up to five soil samples from the continuous core of MW-10 for chemical analysis based on the above-listed criteria; • Submit soil samples for analysis of total petroleum hydrocarbons (TPH) as gasoline (TPHg), TPH as diesel (TPHd) and TPH as motor oil (TPHo); and submit one soil sample that exhibits the highest TPHg concentrations from each boring/well for analysis of benzene, toluene, ethylbenzene and total xylenes (BTEX); methyl tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), di-isopropyl ether (DIPE) and tertiary-butyl alcohol (TBA); ® Collect groundwater samples quarterly from all ten monitoring wells for analysis for TPHg, TPHd, TPHo, BTEX, MTBE, ETBE, TAME, DIPE and TBA; (If product is present in the groundwater, the well will not be purged and a grab groundwater sample will be collected under the product for analysis of TPHg, TPHd, TPHo, BTEX, MTBE, ETBE, TAME, DIPE and TBA.); and Submit a Site Assessment Report prepared by DES following completion of the fieldwork. The EHD approves the work plan with the following conditions: Limit screen sizes to specific intervals of interest to avoid providing vertical conduits for contaminants; Hydrate the bentonite chips for at least thirty minutes before installing the grout; and Quarterly monitor and sample the newly-installed wells for one year; then sample semi- annually after the first year unless directed otherwise. The EHD approval is limited to only methods proposed for the physical installation of the above- mentioned wells. It is not a concurrence or endorsement for any other conclusions, conditions, or implications contained in the DES Work Plan dated 26 May 2015. For your information, the EHD will not enter into a Local Oversight Program (LOP) contract with the State Water Resources Control Board for the next fiscal year (2015-2016). As of 01 July 2015, the EHD will no longer be the lead agency for LOP sites. The EHD will continue to issue the permits for monitoring well and soil boring installations and destruction of all wells and borings at these sites. The EHD will be handing all active LOP cases over to Central Valley Regional Water Quality Control Board (CVRWQCB) to provide oversight and eventual closures of these cleanup cases.