Laserfiche WebLink
' 1.0 Introduction <br /> IT Corporation (M was retained by Pacific Bell to execute the verification monitoring <br /> program proposed in the rr Corporation, Site Investigation Report, Pacific Bell, Facility No. <br /> UE042, 345 North San Joaquin Street, Stockton, California, March 1992. <br /> The verification monitoring program consists of the sampling and analysis of groundwater <br />' samples collected from three off-site monitoring wells. This report summarizes the quarterly <br /> monitoring event conducted during January 1994. <br /> 2.0 Site Background <br />' The Pacific Bell facility located at 345 North San Joaquin Street in Stockton consists of a <br /> building which covers the entire site - half a block (Figures 1 & 2). In December 1990, two <br />' diesel UST's (300 gallon and 550 gallon) located beneath the basement floor in the center of <br /> the facility building were closed in place by filling with a cement slurry. Several borings <br />' were hand bored beneath the tanks and total petroleum hydrocarbons expressed as diesel were <br /> found in the soil as high as 22,000 ppm. <br /> In December 1991, IT Corporation installed three monitoring wells in the streets around the <br /> site (Appendix A). In the soil samples analyzed, no total petroleum hydrocarbons as diesel, <br />' was observed; however, in the upgradient boring, TPH as gasoline was observed (7.4 ppm). <br /> Benzene, toluene, ethyl benzene, and xylenes (BTEX) were identified in soil samples in <br />' MW-2 (downgradient) and MW-1 (upgradient). <br />' BTEX constituents were not observed in any of the groundwater samples collected during the <br /> initial sampling; however, the groundwater samples from MW-1 and MW-2 contained 130 <br /> ppb and 52 ppb TPH as diesel, respectively. Analysis of groundwater samples, collected <br />' during four consecutive quarterly sampling events, revealed no detectable petroleum <br /> hydrocarbons. <br /> 1 <br /> In February 1993, IT Corporation installed six off-site soil borings to examine the extent of <br /> Mpetroleum hydrocarbon migration from the site. Analysis of soil samples from these <br /> boreholes revealed no detectable petroleum hydrocarbons. Analysis of groundwater samples, <br /> collected from the boreholes, revealed no detectable diesel concentrations. No detectable <br /> M7l02-23-94/Us'C194-0016jc 1 <br />