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agricultural pumping and in the Stockton area is generally northeast, toward a large groundwater <br /> ' pumping depression northeast of Stockton. <br /> ' Krazan conducted a subsurface investigation at the site in April 2010 to investigate <br /> recognized environmental conditions identified in a previous Phase I Report. The subsurface <br /> investigation consisted of drilling and sampling ten soil borings throughout the property, <br /> including drilling three soil borings (B 1, B2, and B3) near the inactive wash rack/drain/clarifier <br /> area in the southern portion of the building. Soil samples collected from borings B2 and B3 <br /> contained petroleum hydrocarbons at depths of 10, 15, and 20 feet bgs. No samples were <br /> ' collected beneath 20 feet bgs. Lee & Pierce supervised the drilling and sampling of four <br /> additional soil borings (LPB-1 through LPB-4) near the inactive clarifier in October 2010 to <br /> further investigate the extent of soil contamination beneath the clarifier and to determine if <br /> groundwater beneath the site had also been impacted. Figure 3 presents site detail showing the <br /> locations of the soil borings. Tables 1 and 2 summarize the results of soil and groundwater <br /> samples collected near the inactive clarifier. <br /> ' Based upon the analytical results of soil samples collected at the site, soil beneath the <br /> ' clarifier has been impacted by low to moderate concentrations of petroleum hydrocarbons and <br /> chlorinated solvents. The area of impacted soil appears to extend approximately 12-15 feet from <br /> ' the source (clarifier), and occurs to a depth of approximately 32 feet below ground surface. <br /> Naphthalene was previously detected at a concentration as high as 29 mg/kg (Krazan, April <br /> ' 2010), which exceeds its Preliminary Remedial Goal (PRG) of 4.2 mg/kg for soil in an industrial <br /> setting, as established by the US EPA, Region 9. <br /> ' Only low levels of PCE were detected in groundwater, at levels below the Maximum <br /> Contaminant Level (MCL) of 5.0 µg/L. Based upon the lack of contaminants in boring LPB-4, <br /> located east of the clarifier and near the former waste oil UST, it does not appear that the <br /> ' documented contamination is related to the former USTs that were removed from the site in the <br /> early 1990s. <br /> ' SOIL REMOVAL WORKPLAN [04/13/11] 2 LEE&PIERCE INC. [JOB#107591 <br /> 1 <br />