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' submitted and analyzed for the above referenced tests. Laboratory analyses by the above methods detected no petroleum ' hydrocarbon constituents in the water sample collected from MW-6 or the trip blank (MW-7) . The water sample taken from monitoring well MW--4 was nondetectable for all hydrocarbon constituents except for a concentration of 0. 66 ppb ethylbenzene. The water sample from well MW-5 detected concentrations of TPHG and BTEX at concentrations of 860 ppb, 18 ppb, 4 . 1 ppb, 6. 1 ppb, and 120 ppb, ' respectively. Certified analytical data sheets and chain-or- custody documentation are included in Appendix C and the results of chemical analyses are summarized in Table 2 . 4 . 0 FINDINGS 4 . 1 Groundwater Hydraulic Gradient The groundwater hydraulic gradient was evaluated by triangulation of stabilized depth to water in monitoring wells MW--4, MW-5, and MW-6. The data collected from all 3 wells assumes that all wells are constructed within the same aquifer. TPE believes that all 3 well are hydraulically interconnected. Elevations of the groundwater are shown in Table 3 . Groundwater levels, measured on July 1, 1992, ranged from 9 . 30 to 9 . 10 feet MSL. The ' Groundwater Hydraulic Gradient Map (Figure 3) shows that groundwater beneath the site flows toward the north with a gradient of approximately 0. 002 ft/ft. 1 5. 0 SUMMARY OF FINDINGS Groundwater beneath the site is estimated to flow in a northerly direction with a gradient of 0. 002 ft/ft. CGI measurements made during the field screening of ' soil samples detected only background (< 5 ppm) levels at monitoring wells MW-4 and MW-6. Monitorng well MW-5 GCI readings ranged from background to a high of 45 ppm at 20. 5 feet below grade. Soil samples located at the vadose zone / groundwater interface and showing the presence of hydrocarbons were ' selected for TPHG and BTEX laboratory analysis. In addition, the soil sample showing the highest GCI reading was analyzed for total lead. ' TPHG was not present at concentrations above analytical detection limits in any of the soil samples tested ' except for a sample taken at 20. 5 feet from MW-6. Some petroleum constituents were detected in bor1ng° MW=5' I I I soil samples, taken Gat 1 16 and 20. 5 feet below grade', and a sample taken at 20 . 5 feet from boring MW-6,. I I r r I r E 1 r ' ' e 7 I I �