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volatile hydrocarbons were encountered in the groundwater samples collected from borings <br /> SB-1 through SB-4 and SB-6 upon analysis. The water sample collected from SB-5 revealed <br /> 0.8 ppb toluene only, upon analysis. <br /> ' In March 1993, IT Corporation submitted an "Offsite Investigation Report" to San Joaquin <br /> eP q <br /> County Public Health Services (SJCPHS), Environmental Health Division, requesting site <br /> closure. In a letter dated June 1, 1993, SJCPHS representatives requested further <br /> investigation of soil quality beneath the site building. At this time, the quarterly monitoring <br /> ' program has resumed. In the event that migration of the petroleum hydrocarbons located <br /> beneath the site building is encountered during quarterly monitoring activities, the <br /> ' necessity/feasibility of remedial actions will be addressed at that time. <br /> 3.0 Quarterly Activities <br /> The wells were sampled and groundwater elevations recorded on October 22, 1993. Water <br /> data was collected so gradient and flow direction could be calculated. Sampling procedures <br /> conformed to California Regional Water Quality Control Board and San Joaquin County <br /> Environmental Health guidelines. At least three well volumes of water were purged prior to <br /> the collection of samples. Purging and sampling data is contained in Appendix B. <br />' After purging, each well was sampled with a new Voss Technologies disposable bailer. <br /> Groundwater was transferred directly from the bailer to appropriately preserved bottles <br /> supplied by the laboratory. A distilled water field blank was collected. All sample bottles <br /> were labeled then placed into "zip-loc" bags, sealed with security tape, and placed in a <br />' refrigerated ice chest. Chain of custody forms accompanied the samples at all times <br /> (Appendix Q. <br /> IT Analytical Services in Martinez, California analyzed the TPH as gasoline and diesel <br />' EPA 8015), and BTEX (EPA Method 8020) samples. <br /> 4.0 Summary of Findings <br />' Survey and monitoring data indicated that groundwater flows to the northeast with a gradient <br /> of 0.011 ft/ft (Figure 3). The water table was encountered at approximately 42 feet below <br />' grade. Table 1 contains groundwater elevation data. <br /> MZ(11-W93/UST/93-0082 jf 2 <br />