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2.12 Confirmation Sampling and Analyses After field monitoring procedures indicated that the significantly impacted soil had been removed, confirmation soil samples were collected from the walls and floors of the excavations Sampling locations are identified on Drawing 2-1 Samples were collected according to regulatory guidelines and MARK standard procedures and methods presented in Appendix C The soil samples were submitted to a State of California-certified laboratory for the E following United States Environmental Protection Agency (EPA) analyses ■ Total Petroleum Hydrocarbons as diesel (TPH-d) by EPA Method 8015M; ■ Total Petroleum Hydrocarbons as gasoline (TPH-g) by EPA Method 8015, ■ Benzene, Toluene, Ethylbenzene, and total Xylenes (BTEX) by EPA Method 8020, and ■ Total lead by EPA Method 7421 Laboratory analysis of the confirmation samples collected from the south excavation indicated no detectable petroleum hydrocarbon Analysis of the north pit confirmation samples indicated no detectable hydrocarbons in the north, south and west walls, however, trace levels of petroleum hydrocarbons were present in the floor and east wall samples BTEX constituent concentrations in floor soil sample B1/B2 were 0 082 milligrams per kilogram (mg/kg) benzene, 0 087 mg/kg toluene, 0 008 mg/kg ethylbenzene, and 0 030 mg/kg total xylenes Hydrocarbon concentrations in east wall soil sample EVE2 were 3 6 mg/kg TPH-d, 3.9 mg/kg TPH-g, 0 071 mglkg toluene, 0 042 mg/kg ethylbenzene, and 0 250 mg/kg total xylenes Benzene was not detected in sample EVE2 Total lead concentrations in samples from both pits ranged from 4 2 to 6 6 mg/kg, well below the Total Threshold Limit Concentration (TTLC) as designated by Title 22 of the California Code of Regulations (CCR) Further excavation of the north pit was curtailed due to adjacent buildings and structures FASCLOSE.2 2-2 92-1177102 36