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05 April 1996 AGE-NC Project No 95-0111 Page 4 of 6 ` ' 4 2 GROUND WATER GRADIENT AND FLOW DIRECTION ' The relative elevation of ground water in each well was calculated by subtracting the ground water depth from the surveyed casing elevation(Table 1) All wells were surveyed relative to MW-1, MW-1 was assigned an arbitrary casing elevation of 20 feet The relative ground water elevation ranges from ' 8 12 feet in MW-1 to 5 97 feet to MW-4 Ground water elevation increased an average of 2 feet at the site between July 1995 and March 1996 Free product tluckness was not measurable in MW-4 nor MW-5, however drops of hydrocarbons were observed ' The ground water gradient appears to follow the regional and lustoncaI gradient to the northeast However, a strong localized gradient exists parallel to Grant Line Road, towards the direction of ' MW-5 (Figure 3) ' 43 FIELD AND LABORATORY RESULTS OF SOIL SAMPLES Organic vapors were detected in soil samples collected from MW-5 at concentrations up to 22 parts per million (ppm) No organic vapors were detected in samples collected from MW-6 ' TPH-d was detected in samples from MW-5 at concentrations up to 1,700 (5-foot depth) TPH-d was detected in one_sample from MW-6 (10-foot depth) at 3 2 ppm TPH-g and BTE&X were detected only in sample MW5-5 at concentrations up to 150 ppm The analytical results of the soil samples are ' depicted in Table 2 The laboratory report (MAI Lab ID 61872 to 61876) and chain-of-cu stody are included in Appendix C 4 4 PETROLEUM HYDROCARBON-IMPACTED GROUND WATER TPH-g was detected in samples from MW-4 and MW-5 at concentrations of 570 Acg/l (parts per billion ppb) and 720 ppb, respectively TPH-d was detected in samples from MW-4 and MW-5 at concentrations of 47,000 and 76,000 ppb, respectively Laboratory notations for the samples from MW-4 and MW-5 indicated the presence of free product Benzene was detected in samples collected from MW-1, MW-2, MW-4 and MW-5 at concentrations up to 30 ppb, toluene was detected in MW-5 at 0 72 ppb, ethyl benzene and xylenes were detected in samples from MW-2 and MW5 at concentrations up to 2 1 ppb MTBE was detected in the sample from MW-5 at a 6 0 ppb (confirmed by GC/MS) INopetroleum hydrocarbon were detected in samples from MW-3 or MW-6 Analytical results of the ground water samples are summarized in Table 3 The laboratory report (MAI Lab ID 62283 to 62288) and chain-of-custody are included in Appendix D