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I 3 a' 22 August 2000 AGE-NC Project No 95-0144 Page 5 of 8 TPH-d was detected in 15B-6-6 and 15B-6-10 at concentrations of 520 mg/kg and 220 mg/kg, respectively,but was non-detect in 15B-6-15 TPH-d was not detected in the 15-9 samples,although the detection,limit for TPH-d increased with increasing TPH-g concentrations ' Ethylbenzene was detected in soil sample 15B-6-10 at a concentration of 3,500 gg/kg Xylenes were detected in samples 15B-6-6, 15B-6-10, 15B-9-6 and 15B-9-15 at concentrations ranging from 9 5 ug/kg to 79,000 ug/kg ' Lead was detected in eleven of twelve' samples collected from all 4 soil probe borings at concentrations ranging from 3 5 ppm to 5 9 ppm Analytical results of soil samples are summarized ' on Table 4 The laboratory report (Curtis and Tompkins, Ltd Lab ID Nos 145486-001 through 145486-0,12) and chain-of-custody forms are included in Appendix C 3 2 ANALYTICAL RESULTS OF THE GRAB GROUND WATER SAMPLE ' A grab ground water sample was collected during the May 2000 soil probe boring event from boring 15B-8 TPH-d and TPH-mo were detected in the grab water sample at concentrations of 190 `micrograms per liter (µg/_l)-=a<480 [ig/l, respectively Sample 15B-8-GW contained ! . concentrations of lead„av 12,000 uj g/l l6 analytical results of the grab ground water sample are summarized on Table S�-The laboratory report(Curtis and Tompkins, Ltd Lab ID Nos 145486-013 , through 145486-015) and chain-of-custody forms are included in Appendix C { 33 RELATIVE GROUND WATER ELEVATION AND GRADIENT The elevation of ground water in each wellwas calculated by subtracting the depth to water from the ' surveyed casing elevation(Table 1) Between February 2000 and May 2000,ground water elevation increased 1 89 feet in MW-20B and 1 90 in 1\4W-19B Ground water elevation increased between 142 and 1 78 feet in the other monitoring wells The approximate hydraulic gradient for the May ' 2000 monitoring event was calculated to be 0 0028 ft/ft with a northerly flow direction Ground water elevation contours derived from data collected on 09 and 10 May 2000 are depicted in Figure 3 Ground water was between approximately 2 25 and 7 58 feet above the screened interval in monitoring wells MW-1, MW-2, MW-4, MW-5, MW-8, MW-11, MW-12, MW-13 and MW-18 Ground water was within the screened intervals of MW-19A, MW-20A and MW-21A " ' t Ground water elevations in nested wells MW-19, MW-20 and MW-2l were between 1 35 and 1 61 feet lower in deeper screened intervals beneath a potentially confining clay layer than in the " shallower screened intervals Data from the upper screened intervals, established in first-encountered ground water, was utilized for gradient determination Advanced GeoEnvironmental,Inc I » u