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Pombo Property Soil & Groundwater Sampling Boring B-8 located at 24124 Lammers Road barn encountered tan silty plastic clays ' grading into tan very fine grained, well sorted, silty sands similar that encountered in the fuel storage area. 3.2 Soils Contamination i Laboratory results of analyses of soil samples collected in the investigation are presented in Appendix A and summarized in the table of Soil and Groundwater Laboratory Sample Results.. Gasoline and diesel range petroleum hydrocarbons and fuel additives were detecte the laboratory samples collected from borings B-3 and B-5 located in the areas of a previously removed underground fuel tanks. The hydrocarbon contamination appears to be related to the use of the tanks. Analysis of soil samples collected from the above ground storage tanks, the Truck and ' Trailer Wash, and the 24124 Lammers Road barn did not detecteA contamination. 3.2 Groundwater Contamination Laboratory results of analyses of groundwater samples collected in the investigation ' are presented in Appendix A and summarized in the table of Soil and Groundwater g Laboratory Sample Results. 2.7ug/1 MTBE was detected in the groundwater sample from Boring B-1. 56 mg/l gasoline range petroleum hydrocarbons, 3700 ug/l '0 benzene, 1200 ug/l toluene, 2400 ug/1 ethyl benzene, 4000 ug/1 total xylenes, and 1900 ug/l MTBE were detected in the groundwater sample from Boring B-3. 0.09 mg/l gasoline range petroleum hydrocarbons, 7.1 ug/l benzene, 6.9 ug/l ethyl ' benzene, 11 ug/1 total xylenes, 7.9 ug/l MTBE, and 2.1 mg/1 motor oil range petroleum hydrocarbons were detected in the groundwater sample from Boring B-4. 0.5 mg/1 gasoline and 100 mg/l diesel range petroleum hydrocarbons, 0.9 ug/1 ' toluene, 5.3 ug/1 ethyl benzene, 13 ug/l total xylenes were detected in the groundwater sample from Boring B-5. 1.5 mg/1 motor oil range petroleum hydrocarbons were detected in the groundwater sample from Boring B-7. The concentrations of petroleum hydrocarbons, benzene, toluene, ethyl benzene, total xylenes, and MTBE detected in the groundwater samples exceed the .' established water quality goals for groundwater in the Tracy area. 4.0 CONCLUSIONS AND RECOMMENDATIONS ' The significant levels of soil and groundwater contamination disclosed during this . investigation appear to be associated with the former underground storage tanks at this ' site. Pesticides and chlorinated compounds (refrigerants) were not found in any of the samples analyzed for the materials. ' The extent of the petroleum contamination in the soil and groundwater is unknown. • Laboratory samples obtained in the vicinity of borings B-3 and B-5 were low to non- 1 ' S i