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U f HYDRO INVIRONIMMAL TECHNOLOGIES,INC. 3.0 RESULTS AND DISCUSSION 3.1 Site Stratigraphy Sediments encountered during this phase of drilling consisted primarily of silty sand overlying fine to medium grained sand with some lean clay and lean clay with sand from ground surface to 30 feet below grade The stratigraphy encountered during this phase of drilling is generally consistent with that encountered during the previous phase Complete soil sample descriptions are presented on the Soil Boring Log and Well Construction Diagrams in Appendix C. 3.2 Results of Soil Sample Analysis Neither TPHg nor BTEX were detected in concentrations exceeding the method detection limits in soil samples collected from borings MW-7 and MW-8 A summary of soil sample analytical results is presented on Table 1 A copy of the laboratory reports and chain-of-custody forms are attached in Appendix E 3.3 Ground Water Gradient Ground water was initially encountered during drilling at depths of 20.5 and 25 5 feet below grade in borings MW-7 and MW-8, respectively On December 9, 1993, the depth to ground water in each of the wells ranged from 17 22 to 18 85 feet below grade. Depth to water measurements and wellhead elevation data were used to calculate ground water elevation contours. These contours are shown on Figure 3, the Ground Water Contour Map Figure 3 shows the ground water flow to be towards the northwest at an approximate gradient of 0 0006 ft/ft (0 06%'0) 3.4 Results of Ground Water Sample Analysis TPHg was not detected in concentrations exceeding the method detection linuts in ground water samples collected from monitoring wells MW-4, MW-6, MW-7 and MW-8 TPHg concentrations ranged from 230 parts per billion (ppb) in the ground water samples collected from MW-2 to 1,200 ppb in the ground water samples collected from MW-1 Benzene was not detected in concentrations exceeding the method detection limas in ground water samples collected from monitoring wells MW-3, MW-4, MW-7 and MW-8 Benzene concentrations ranged from 16 ppb in the ground water sample collected from MW-6 to 95 ppb in the ground water �I sample from MW-1 A summary of ground water elevations and sample analytical I ' i results is presented on Table 2 , Hydrocarbon' concentrations are displayed graphically on the Hydrocarbon 'Concentration Map (Figure 4) A copy of the laboratory reports and chain-of-custody forms are attached in Appendix E I t t V i V I I l f I �I I 4 l tl Ill I' IIT li ill it V � VI i I Y I