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J&L Market • 4 • <br /> 8125 S. EI Dorado St., French Camp 8 May 2013 <br /> San Joaquin County <br /> Site Geology and Hydrogeology <br /> Site lithology consists of clay, silt, and sand to 141' bgs, the maximum extent of investigations <br /> (Figures 6, 7, and 8). Groundwater flow direction varied from northeast to southeast, and by <br /> zone (Figure 9 shallow, Figure 10 intermediate, and Figure 11 deep). The groundwater gradient <br /> varied from 0.0004 to 0.024 ft/ft. <br /> Residual Mass Calculation <br /> The consultant did not estimate TPH removed during soil over-excavation, nor give residual <br /> mass estimates for soil and the mass removed by the ozone pilot study. In September 2011, <br /> the consultant estimated approximately 14.65 lbs. of TPH remained in groundwater, based on <br /> the June 2011 spike in concentrations. Groundwater concentrations had declined almost and <br /> order of magnitude by March 2012. Figure 12, Graphs 1 through 3 show TPHg should reach <br /> water quality goals (WQGs) by 2020; benzene should reach WQGs by 2015; and 1,2-DCA <br /> should reach WQGs by 2030. <br /> Public Participation <br /> Public participation was conducted from 23 July 2012 to 10 September 2012 with no adverse <br /> comments. <br /> Low Risk Closure Policy (LTCP) Review <br /> The Site qualifies for a low risk closure under the State Water Resources Control Board Low <br /> Risk Closure Policy, based on the following rationale: <br /> Groundwater Specific Criteria <br /> (5) a. The regulatory agency determines, based on an analysis of site specific conditions that <br /> under current and reasonably anticipated near-term future scenarios, the contaminant plume <br /> poses a low threat to human health and safety and to the environment and water quality <br /> objectives will be achieved within a reasonable time frame. <br /> While the nearest supply wells are 200' from the site, the monitoring well data indicate a low <br /> probability that the plume will leave the Site. See above Table (second table) and Sensitive <br /> Receptor Survey section. <br /> Petroleum Vapor Intrusion to Indoor Air <br /> Appendix 3, Scenario 3, Figure B. Benzene in groundwater <1000 ug/L and TPH in soil <100 <br /> mg/kg down to 10' bgs. Site is also exempt due to LTCP status as an active fueling station. <br /> See Risk Assessment and Table 2 above. <br /> Direct Contact and Outdoor Air Exposure <br /> a. Maximum concentrations of petroleum constituents in soil are less than or equal to those <br /> listed in Table 1 for the specified depth below ground surface (bgs). The concentration limits for <br />