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• Jet fuel-weight petroleum hydrocarbons were detected in soil at a depth of 10 feet bgs at a <br /> concentration of 10,500 mg/kg at the south end of the vehicle inspection rack. Oil-weight <br /> petroleum hydrocarbons were also detected in soil at this location at a concentration of 153 <br /> mg/kg. TPH-g and TPH-d were detected in soil at a depth of 25 feet bgs at maximum <br /> concentrations of 25.4 mg/kg and 209 mg/kg,respectively. <br /> 6.0 RECOMMENDATIONS <br /> The following recommendations are made based on the information and opinions presented and <br /> expressed in this report. The recommendations are presented for each investigated area of the <br /> Stockton CA ARNG facility. <br /> 6.1 AASF <br /> A potentially residual impact to soil from TPH-g was detected in the location of a release from a <br /> former wash rack, paint spray booth, and battery storage in the southwest corner of the AASF. <br /> The release from the former washrack in this area has been remediated to the satisfaction of the <br /> CVRWQCB. Indication of impact to soil from the former paint spray booth and battery storage <br /> was not detected in boring B-3. Versar does not believe further investigation is warranted in this <br /> area. <br /> Elevated concentrations of zinc were detected in shallow soil adjacent to a former clarifier <br /> location near the aircraft fueling facility. No other indication of release was detected in boring <br /> B-1. The elevated zinc concentrations are well below regulatory action levels for protection of <br /> human health, and hazardous waste classification. Versar does not believe further investigation <br /> is warranted in this area. <br /> Groundwater does not appear to have been actionably impacted by a release of petroleum <br /> hydrocarbons to soil from former USTs in the AASF fueling area. Versar recommends <br /> requesting case closure from the lead regulatory authority, and subsequently removing the three <br /> groundwater monitoring wells. <br /> 6.2 CSMS <br /> An elevated concentration of lead was detected in shallow soil beneath the former location of a <br /> battery storage room in the north portion of the CSMS building (boring B-12). The <br /> concentration of lead is well below state and federal action levels, is inaccessible to CSMS <br /> personnel, and is overlain by impermeable barriers. Versar does not believe further investigation <br /> is warranted in this area. <br /> Oil-weight petroleum hydrocarbons were detected in soil just west of the carpenter shop building <br /> • (boring B-14), and at the former location of hazardous materials storage east of the carpenter <br /> 2187-01/3134-100/MAY26'00 16 <br />