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5.0 LABORATORY RESULTS 5.1 Excavation Samples �. Very low concentrations of gasoline -range hydrocarbons were detected in samples from the north end of tanks #2 and #3 (Tab] 1). Both of these samples appear to be depleted of volatile L compounds (benzene) and enriched in the less volatile xylenes and ethylbenzene. L TABLE 1 L No hydrocarbons were detected above mandatory detection limits in the samples from the south enJ of tank #3 and north end of tank # 1. Moderate to high concentrations of hydrocarbons were detected in samples from the south ends of tanks #1 and #2. This supports the field observation of significant staining and strong odors 6. beneath these tanks. Based on the detected concentrations and the generally sandy texture of the soil, soil contamination in the center of the excavation probably extends to a depth of several feet telow the present floor. The sample from the waste -oil tank was analyzed for both diesel -range hydrocarbons and oil and 6. grease, in addition to gasoline -range hydrocarbons (Table 2). (hely xylene was detected. This sample was also analyzed for volatile ltalocarboas and semi -volatile hydrocarbons, including hw PCB's, and for five priority metals. Very low concentrations of dichlorobenzene and naphthalene were detected, and metals concentrations were within background ranges for the Stockton area. 6. Summary of Analytical Results: Alpine BP � Skil Mat: ix v. All result are in mg/kg (ppm) IDM Bate Ggsolinc Diesel t ead _— Benzene Toluene Ethylbenzene Xylenes �- 3S 9/14/94 ND --- ND ND ND ND ND 2S 19,000 ---- 10 1 12 650 410 3,000 L 1S 8,500 ---- 15 ND 55 94 750 IN ND ---- 4.9 ND ND ND ND 2N ND ---- 4.1 ND ND ND 0.029 �- 3N ND ---- ND ND 0.019 0.010 0.086 L ND = Not Detected ---- = Not analyzed L No hydrocarbons were detected above mandatory detection limits in the samples from the south enJ of tank #3 and north end of tank # 1. Moderate to high concentrations of hydrocarbons were detected in samples from the south ends of tanks #1 and #2. This supports the field observation of significant staining and strong odors 6. beneath these tanks. Based on the detected concentrations and the generally sandy texture of the soil, soil contamination in the center of the excavation probably extends to a depth of several feet telow the present floor. The sample from the waste -oil tank was analyzed for both diesel -range hydrocarbons and oil and 6. grease, in addition to gasoline -range hydrocarbons (Table 2). (hely xylene was detected. This sample was also analyzed for volatile ltalocarboas and semi -volatile hydrocarbons, including hw PCB's, and for five priority metals. Very low concentrations of dichlorobenzene and naphthalene were detected, and metals concentrations were within background ranges for the Stockton area. 6.