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i MAANGE{6 ESGNFASTANSlRIN'15 i4.1 GROUNDWATER GRADIENT AND DIRECTION iBefore sampling, the depth to water was measured from surveyed points on the top of each well casing This data (presented in Table 1) was used to generate Figure 3 which shows the ' groundwater gradient and flow direction Groundwater in the vicinity of the former tank pit flows in a northeasternly direction along a north trending trough. The groundwater flow ' direction agrees with previous findings 4.2 ANALYTICAL SUMMARY r Both soil and groundwater samples were analyzed for TPH-g and BTEX using EPA Method ' 8015m and 8020, respectively Soil samples were also analyzed for TPH-d using EPA Method 8015 The method detection limit (DL) for TPH-g is 1 0 mg/kg for soil and 50 µg11 for water The DL for TPH-d in soil is 1 0 mg/kg The DLs for BTEX are 0.5 µg11 for water and .005 img/kg for soil iThe results of the soil and groundwater analyses from Phase III are summarized in Table 2. The complete laboratory analytical reports are presented in Appendix C. i � 4.3 SOIL SAMPLE RESULTS iAs shown on Table 2, only soil samples from MW-2A replacement well contained quantifiable chemical concentrations. This well was located along the south boundary of the 1988 tank iexcavation i TPH and BTEX concentrations were highest in the capillary fringe zone sampled at 45 feet bgs, where small beads of product were observed on soil during drilling No petroleum constituents itested for were detected in the three soil samples from MW-3A 4.4 GROUNDWATER SAMPLE RESULTS The bottom portion of Table 2 presents the groundwater sample analytical results As shown ion the table, petroleum constituents were detected in only two of the seven wells MW-2A, which is closest to the former tank pit, contained the highest concentration of petroleum I constituents in groundwater Floating product was encountered during the drilling of this well. MW-8, which is downgradient of the source area, contained 820 µg11 of TPH-g and 0 59 µg11 of benzene. Petroleum constituents were non-detectable in all other wells. i UPROJ[iCMSAMJOQ' SW"HASE M 6 29 Auvm 1995