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samples were: stored on ice and transported to McCampbell Analytical <br /> in Pacheco. The samples were analyzed for TPH as gasoline and <br /> I diesel and BTE&X in accordance with EPA methods 8015m and 8020, <br /> respectively. The contaminated stockpile was then spread to allow <br /> access to monitoring well MW-1 and to facilitate future <br /> remediation. <br /> 3 . 6 Groundwater Monitoring <br /> On September 9 , 1993 , representatives of GeoAudit visited the site <br /> to perform quarterly monitoring. Water depths were measured, wells <br /> were purged, and groundwater samples were collected. <br /> 3 . 6. 1 Monitoring Well Purge Procedures <br /> A Solinist water level meter was used to measure the depth to water <br /> I in the four monitoring wells (Table 1) . The wells were then purged <br /> of 7 to 9 gallons using a three-stage purge pump. Temperature, pH <br /> and conductivity of the purge water were measured at one-gallon <br />' intervals using a Hydac water analyzer (Table 2) . The water was <br /> stored on site in DOT-approved drums. <br /> 3 . 6.2 Groundwater sample Collection <br /> Water samples were collected from the four wells in 40-m1 EPA vials <br /> and 1-liter amber bottles using disposable plastic bailers. The <br />' samples were transported in a chilled container to McCampbell <br /> Analytical in Pacheco and analyzed for TPH as gasoline and diesel <br /> and BTE&X in accordance with EPA methods 8015m and 602 . <br /> 1 <br /> 4 . 0 FINDINGS <br />' 4 . 1 Analytical Results of Excavation Samples <br /> Petroleum hydrocarbons were detected in sample TP-3 (north wall of <br />' excavation) at levels of 350 mg/kg (TPH-g) and 160 mg/kg (TPH-d) <br /> (parts per million) . TPH as gasoline and diesel were also detected <br /> in sample TP-7 at levels of 1.4 ppm and 1. 4 ppm, respectively. <br />' Benzene and ethylbenzene were detected only in sample TP-3 (0. 082 <br /> PPM and 2 . 7 ppm) . Toluene was detected in all soil samples at <br /> levels to 0 . 92 ppm. Xylenes were detected in five soil samples at <br />' levels to 11 ppm. Laboratory results are summarized on Table 3 . The <br /> laboratory report and chain of custody are included in Appendix B. <br />' 4.2 Analytical Results of stockpile Samples <br /> Average concentrations for all petroleum hydrocarbons are very low <br /> within the stockpiled soil. Six of the fourteen samples analyzed <br /> were reported as "not detected" for TPH and BTE&X (Table 4) . Only <br /> two samples had TPH-g concentrations of more than 10 ppm, and only <br /> 9 <br />