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Petroleum Hydrocarbons as gasoline (TPH-g), and 8020 for benzene, toluene, ethylbenzene, and xylene (BTEX) four soil samples and six water samples were also analyzed for Total Petroleum Hydrocarbons in the diesel range (TPH-d) All water samples were also analyzed for five gasoline oxygenates and dichloroethane (1,2-DCA) The laboratory report is included in Appendix B, and'the results are discussed in section 40 4.0 RESULTS 4 1 Soil Samples Table 1 shows the laboratory results for all borehole samples that have been collected in the three phases of drilling Whereas several samples from the first two phases contained detectable concentrations of gasoline hydrocarbons, hydrocarbons were detected in only three of the eighteen samples collected in this phase The laboratory reported that strongly aged gasoline (TPH-g) was detected at a concentration of 8 2 milligrams per kilogram (mg/kg=parts per million) in JLM-9-18' Toluene was also detected in this sample The sample was collected at a drilled depth of 18 feet, which corresponds to a vertical depth of approximately 17 feet For compartsbn, a concentration of 4,200 mg/kg was detected in sidewall sample JL-P-15 at a depth of 12 5 feet and a concentration of 1,300 mg/kg was detected in borehole sample JLM-2-20' at a depth of 20 feet Figure 3 shows the westward decline in gasoline concentrations recorded by these samples • The laboratory also reported that a concentration of 4 0 mg/kg was detected In one sample using EPA method 8015 for extractable petroleum hydrocarbons (Total Petroleum Hydrocarbons in the diesel range) This sample was collected at a depth of 20 5 feet in boring JLM-11 (Table 1) Longer-chain (heavier) hydrocarbons in the motor oil range were also significant in the sample, but it is uncertain whether the results actually represent diesel fuel or weathered gasoline ' The main purpose of collecting the soil samples was to identify the western limit of the contaminated soil that was left in place beneath the building during the 1995 interim remediation work, and to determine whether the soil contamination that was identified in boring JLM-5 in 2002 was also part of that impacted area or represented a separate area of impact The data from the thew borings indicate that impacted soil is primarily limited to the area near the northern end of the service station building As shown in Figure 4, the impacted area is centered in the vicinity of JLM-2, JLM-9, and JLM-5 Only one petroleum source is required to explain the distribution of the impacted soil, and the pipeline that carried fuel from the UST's to the dispenser islands is the likely culprit, 4.2 Water Samples I The analytical results for water samples are shown in Table 2 It is clear that gasoline is present, but concentrations reported by the laboratory as TPH-g were low and only two water-table samples exceeded the 50 part-per-billion detection limit The laboratory reported TPH-g concentrations of 160 µg/l and 170 µg11 in the two samples from beneath 5