ARCHIVED REPORTS XR0001334 - Laserfiche WebLink

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l August 11, 1992 'W" IM Working To Restore Nature ARCO Service Station 2168, Stockton, California i Product Line Sampling On April 28, 1992, while clearing underground utilities, a product line was accidently k fractured and subsequently leaked approximately 2 to 5 gallons into adjacent soil. To evaluate the effects of the leak, RESNA collected a soil sample above the product line (S-1- PL1) and a sample below the product line (S-5-PL2) for laboratory analyses. Analytical Methods Soil samples were analyzed for TPHg using modified Environmental Protection Agency (EPA) Method 8015 and benzene, toluene, ethylbenzene, and total xylene isomers (BTEX) using EPA Method 8020. Soil samples collected near the waste-oil tank were also analyzed for polychlorinated biphenyls (PCB) using EPA Method 8080, total extractable C8 - C30 hydrocarbons (TEH) using modified EPA Method 8015, halogenated volatile organic compounds (HVO) using EPA Method 8010, total oil and grease (TOG) using gravimetric Method 5520E/F, and cadmium, chromium, hexavalent chromium, lead, zinc, and nickel. Laboratory analyses were performed at Sequoia Analytical in Sacramento, California (Hazardous Waste Testing Laboratory No 1624) Results of analyses are summarized in Table 1 and Table 2 Results of Analyses of Soil Sales Results of laboratory analyses indicated TPHg and BTEX were detected in soil samples collected from at 1 feet (45 ppm) and 5 feet (4,100 ppm) bsg adjacent to the fractured f product line Trace to low concentrations of residual gasoline hydrocarbons were detected in boring B-6 drilled near the waste-oil tank the highest concentration of 43 ppm of TPHg was detected in the sample collected at the capillary fringe, approximately 40 feet below surface grade. ! Trace concentrations of TPHg and/or BTEX compounds were detected in the samples from boring B-5 and B-12 drilled in the vicinity of the existing UST's. The highest concentrations of gasoline hydrocarbons in these borings were at approximately 26 feet bsg (40 ppm in boring B-1). Data from bonngs B-3, B-4, and B-5 delineate the lateral extent of gasoline hydrocarbons east of the existing UST's The concentrations of TPHg detected in soil from borings B-8 through B-11 ranged from below detection limits to 160 parts per million(ppm) and BTEX concentrations ranged from below detection limits to 12 ppm of total xylene isomers. The highest concentrations of TPHg in these borings were detected in samples from 31.5 feet bsg in borings B-9 (150 ppm) and B-10 (160 ppm). 1 3100" � 3 1