ARCHIVED REPORTS_XR0007282 - Laserfiche WebLink

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Appendix A - Historical Background • g Rover City Petroleum and Connell Motor Lift Truck Page 6 of 14 anal samples zed P Y • Chlorinated volatile organic compounds (generally VOCs), specifically tetrachloroethene (PCE), were detected in three soil samples collected from between 45 feet to 55 feet bsg PCE was detected at a maximum concentration of 68 micrograms per kilogram (µg/kg) m soil samples collected from depths of 45 feet to 55 feet bsg 1,2-DCE was detected in soil samples collected between 45 feet and 65 feet bsg, at decreasing concentrations with increasing depth In addition, 1,2-Dichlorobenzene was detected at concentrations less than 68 µg/kg in the soil samples analyzed • The most intensely hydrocarbon-impacted soil was encountered in the area west of the truck bay building,in borings P26 and P27 Soil contamination between depths of 10 feet bsg and 55 feet contained the highest hydrocarbon concentrations encountered Moderate concentrations of TPH(1,000 mg/kg)and low concentrations(>10 mg/kg)were detected in the remaining boring samples at depths between 20 and 55 feet bsg • The lateral extent of impacted soil,between 35 feet and 55 feet bsg,was limited toward the west by soil boring P28 and the lateral extent of impacted soil between 30 feet and 45 feet bsg was limited to the south by soil boring M1 • A ground water sample collected at the southern most end of the site contained TPH-d and toluene at concentrations of 110 micrograms per liter (µg/1) and 0 81 µg/1, respectively There was an UST site located directly south, that was closed by the RWQCB, which may be a potential source of the TPH-d impacted ground water December 2000 -Additional Site Assessment In order to define the lateral and vertical extent of soil contamination and determine if ground water had been impacted by the unauthorized release(s)of solvents,AGE advanced four CPT soil borings P30 to P33 to depths ranging from 80 to 100 feet below surface grade(bsg)in December 2000, grab water and soil samples were collected from selected depths Based on the CPT data, generally, fine-grained soil was penetrated in the soil borings, however several sand intervals were locally encountered in two of the four CPT borings Sand was encountered at depths between 25 and 30 feet bsg m CPT P30 and at depths of 30 and 35 feet bsg in CPT P31 Sand and gravel were encountered at a depth of 30 feet bsg Sand,locally cemented or consolidated,was encountered at a depth of 80 feet bsg in three CPT soil borings,P30,P32 and P33 The deeper sand unit encountered in borings P32 and P33 was well indurated and caused CPT-data probing refusal at the two referenced locations Variable lithology including silty sand, silt and Advanced GeoEnvironmentai,Inc