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Jonas & Associates Inc. <br /> ' the north-northeast [(OW-2, 14,000 parts per billion (ppb)], 65 feet to the north- <br /> northeast (OW-6, 11 ppb) and 40 feet to the south (OW-3, 59 ppb) of the former <br /> UST location (PG&E, 1988) <br /> 3 2 2 BTEX - 1988 Analytical Results <br /> BTEX were detected during this investigation in soil samples collected <br /> approximately 10 feet to the north-northeast (OW-2) of the former UST location <br /> (benzene, up to 16 ppm, toluene, up to 17 ppm, ethylbenzene, up to 45 ppm, <br /> xylenes, up to 83 ppm), at depths near the encountered water table <br /> 3 2 3 EDB, 1,2-DCA and PAHs - 1988 Analytical Results <br /> EDB 1,2-DCA and PAHs were not detected in any grsamples les collected <br /> P <br /> during the November 1986 field investigation or the 1988 investigation (PG&E, <br /> 1988) <br /> ' 3 2 4 Lead - 1988 Analytical Results <br /> Total lead appeared in all soil samples in concentrations ranging from non- <br /> detectable to 11 ppm Total lead (0 05 ppm) was found in one water sample <br /> collected from well OW-5 near the detection limit All lead concentrations found in <br /> soil samples were within a range typical of natural conditions There appeared to <br /> be no correlation between the distributions of lead and hydrocarbons at the Service <br /> Center <br /> 33 1989 through 1995 Groundwater Investigations <br /> Quarterly groundwater monitoring has been performed on all six wells from April <br /> 25, 1989 through November 21, 1995 Table 3-8 provides a summary of <br /> groundwater monitoring data from 1989 to 1995 Figure 3-7 presents a <br /> groundwater elevation contour map for the fourth quarter 1995 groundwater <br /> 1 monitoring event, which is representative of the hydraulic gradient direction <br /> encountered continuously since 1989 <br /> ' As indicated in Figure 3-7, monitoring wells OW-2, OW-4, OW-5, and OW-6 are <br /> downgradient of the former UST OW-2 is the only well which has ever shown any <br /> level of gasoline contamination <br /> As indicated in Table 3-8, during the last four consecutive quarterly sampling <br /> events, TPH-G and TEX were not detected in any of the wells Benzene (0 72 ppb) <br /> 11 <br /> 1 <br />