SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Jamar Service • 0 December 2013 4075 East Main Street, Stockton Claim No: 14482 Other designated beneficial uses of impacted groundwater are not threatened, and it is highly unlikely that they will be, considering these factors in the context of the site setting. Rationale for Closure under the Policy • General Criteria: The case meets all eight Policy general criteria. • Groundwater Specific Criteria: The case does not meet Policy criteria because the contaminant plume is not defined to the northeast, the dissolved concentrations of MTBE are greater than 1,000 micrograms per liter (Ng/L), and the nearest water supply well is 534 feet northeast (downgradient) of the Site. • Vapor Intrusion to Indoor Air: The case meets the Policy Exclusion for Active Station. Soil vapor evaluation is not required because the Site is an active commercial petroleum fueling facility and the release characteristics do not pose an unacceptable health risk. • Direct Contact and Outdoor Air Exposure: This case meets Policy Criterion 3b. Although no document titled `Risk Assessment' was found in the files reviewed, a professional assessment of site-specific risk from exposure through the direct exposure pathway was performed by Fund staff. The assessment of site-specific risk from potential exposure to residual soil contamination found that maximum concentrations of petroleum constituents remaining in soil will have no significant risk of adversely affecting human health. The Site is paved and accidental exposure to site soils is prevented. As an active petroleum fueling facility, any construction worker working at the Site will be prepared for exposure in their normal daily work. Objections to Closure and Responses According to the Path to Closure page in GeoTracker, the County opposes closure because: • Secondary source remains. RESPONSE: Secondary source as defined by the Policy was removed by excavation in 1998 and soil vapor extraction conducted between October 2001 and May 2013. • The case does not meet Policy groundwater criteria. RESPONSE: We concur. Recommendation The Fund recommends that the County direct the Responsible Party to continue groundwater monitoring since some site wells are too new to establish a reliable trend and that the County direct the Responsible Party to further evaluation of the contaminant plume to the northeast. l Kirk Larson, P.G. Date Robert Trommer, C.H.G. Date Engineering Geologist Senior Engineering Geologist Technical Review Unit Chief, Technical Review Unit (916) 341-5663 (916) 341-5684 Page 2 of 14