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07 January 1997 <br /> AGE-NC Project No 96-0266 <br /> Page 3 of 6 <br /> in the P 1-20 sample <br /> Petroleum hydrocarbons were detected in the grab water samples collected in the former UST <br /> excavation in San Jose Street and in each additional grab water samples collected The water sample <br /> collected from probe boring P 1 contained TPH-g at 44,000 micrograms per liter ug/L (parts per <br /> billion ppb), benzene at 870 ppb and xylenes at 7,800 ppb The water sample collected from probe <br /> boring P4 contained no detectable TPH-g, benzene or ethylbenzene The water sample collected <br /> from probe boring P4 contained 0 6 ppb of toluene and 1 8 ppb of xylene TPH-g was detected in <br /> the water sample collected from probe boring P5 at 94 ppb, benzene at 0 6, toluene at 0 88 and <br /> xylene at 16 ppb, respectively The grab water sample collected from probe boring P3 did not <br /> contain detectable concentrations of TPH-g The only BTE&X compound detected was xylene at <br /> 15 ppb <br /> Surface soil samples collected in the vicinity of Building 1, the location of a metal plating shop, <br /> contained lead at 110 ppm and the STLC concentration for lead detected in the same soil sample was <br /> quantified at 2 5 micrograms per liter <br /> • 4.0. REGIONAL GROUND WATER ELEVATION <br /> The estimated depth to ground water at this property is approximately 10 to 20 feet below surface <br /> grade (bsg), based on information from Lines of Equal Depth of Water Wells, Fall 1995 published <br /> by the San Joaquin County Flood Control District and Water Conservation District However, the <br /> PHS-EHD records indicted that the highest ground water elevation was observed in 1986 at 10 feet <br /> bsg The prevailing ground water flow in western Stockton flows generally to the west, while <br /> localized ground water flow may vary during winter/summer cycles Ground water was observed <br /> at twelve feet bsg during the limited subsurface investigation <br /> 5 0 SCOPE OF WORK <br /> 5 1 PROBING AND SAMPLING <br /> An additional subsurface investigation at the site is necessary to determine the lateral and vertical <br /> extent of hydrocarbon-impacted and metals-impacted soil and/or ground water at the site AGE <br /> proposes to advance a minimum of ten soil probe borings at the site Probe bonngs will be advanced <br /> to depths of approximately 15 feet (below ground water), using direct push technology (DPT) <br /> • Four probe boring will be advanced near the boarder of the site to the west Two probe boring will <br /> be advanced surrounding the former UST in the City of Stockton right-of-way, in conjunction with <br />