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5.0 CHEMICAL ANALYTICAL 5.1 Analytical Methods Soil and groundwater samples were analyzed by ENVIRO-CHEM, INC., a State of California, Department of Health Services (DHS) certified laboratory. Selected soil samples were analyzed for TPH (C4-CA, BTEC and MTBE, in general accordance with EPA method nos. 8015 modified (for TPHg) and 8021 B (for BTEX and MTBE). Fewer selected samples were also analyzed for fuel oxygenates in general accordance with ii'riited EPA method no. 82GOB. All groundwater samples were analyzed for TPHg, BTEX and fuel oxygenates in general accordance with EPA method nos. 8015 modified (for TPN) and limited 8260B (for BTEX and oxygenates). K .,,'.: soil Samples Attached Table 1 summarizes the results of the soil sample analyses. A review of the data in Table 1 reveals the following major observations: • In borings B1 and g2 (drilled west of the Maintenance Department building), only samples from 20 feet or below (i.e. at or below the capillanj fringe) were reported to contain any detected TPH gasoline and/or BTEX. All reported concentrations in these borings were relatively minor; • In borncg. B3 (drilled near former UST#1), significant detected concentrations of TPH (gasoline & kerosene range), as well as TEX compounds, were reported in soil samples from 10 feet and deeper. No benzene or MTBE was detected in samples from this boring. The maximum reported concentrations in B3 samples were; 4,960 mg/kg (TPH gasoline range), 2,940 mg/kg (TPH kerosene range), 209 mg/kg (toluene), 106 mg/kg (ethylbenzene), and 542 mg/kg (xylenes). All samples from borings B7 and 68 (two borings stepped out laterally from B3)were reported to contain no significant detected TPH, BTEX or MTBE; • In boring B4 (drilled in the equipment washing area), the two foot deep sample was reported to contain 222 mg/kg of TPN (oil range), All other deeper samples were reported to contain no detected TPH, BTEX or MTBE; • In borings B5 and B6 (advanced across the fence from a leaking UST on the property adjoining the west-southwest site corner), no detected TPH, BTEX or MTBE was reported in any of the soil samples; • No detected benzene or MTBE was reported in soil samples from any of the soil borings. It is noted that a few soil samples with detected TPH had increased detection limits for benzene and MTBE; and • Selected soil samples from most soil borings were also; analyzed for other fuel oxygenates (DIPE, TAME, TBA, ETBE). None were reported in any of the analyzed soil samples. Details of the chemical analyses results are provided in the laboratory reports in attached Appendix C. Proj. No.: 04483-01 4 of 7 AEM