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UM �- <br /> L Ms.Michelle Le <br /> San Joaquin County Environmental Health Department <br /> February 7,2006 <br /> L Page 4 <br /> and January 3, 2006). Analytical results of the composite samples from the over-excavated soil (SP-13- <br /> 14, SP-15-18 and SP-19-22)indicated that GRO was present at a maximum concentration of 620 mg/kg, <br /> 1. toluene at 1.5 mg/kg, ethylbenzene at 3.7 mg/kg, and xylenes at 29 mg/kg. Due to the presence of <br /> petroleum hydrocarbons, the over-excavated material was hauled off site by Dillard Environmental and <br /> disposed of at Forward Landfill in Manteca, California. The soil disposal manifests are presented as <br /> ` Attachment E. <br /> Summary of Activities and Findings <br /> • Three 12,000-gallon, double-walled fiberglass USTs were removed on December 29, 2005. <br /> The tanks were in good condition with no apparent holes or cracks. <br /> L • Soil in the southwest comer of the UST pit and beneath two of the dispensers was stained <br /> and had a strong petroleum odor. <br /> • Significant concentrations of petroleum hydrocarbons were identified in UST pit sample <br /> L PB-3 and dispenser samples DI-1 and DI-4. Benzene was not identified at or above the <br /> reporting limit in any of the soil samples collected. Oxygenates/additives were not identified <br /> in any of the soil samples, with the exception of one detection of TBA in sample DI-3 <br /> (0.039 mg/kg). <br /> • Approximately 57 cubic yards of soil from beneath the southwest comer of the former UST <br /> complex and two of the dispensers were over-excavated to approximate depths of 21 and 13 <br /> feet bgs,respectively. <br /> • Over-excavation was discontinued prior to removal of all impacted soil because of <br /> equipment limitations and interference from an overhead service canopy. <br /> • At the total depth of the tank and dispenser over-excavations, evidence of petroleum <br /> hydrocarbons persists. In the tank pit, stained soil with a petroleum odor was still present <br /> prior to backfilling. Analytical results of confirmation soil samples collected at the <br /> dispenser over-excavation identified concentrations of petroleum hydrocarbons. <br /> Clean stockpiled materials were used as backfill at the site. Stockpiled materials containing <br /> Lpetroleum hydrocarbons were hauled off site for proper disposal. <br /> LCONCLUSIONS <br /> Based on the analytical data collected during the above-described fieldwork, detectable concentrations <br /> L of petroleum hydrocarbons remain in soil near the southwest corner of the UST complex and beneath <br /> two of the dispenser areas. Quarterly groundwater monitoring will continue at the site. <br /> L <br /> KAWpro mV5 BP"COb0595\05 UST Re va]\UST Remmal Rpt.dm <br />