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Table 4 summarizes the analytical results. In every case, no concentrations of petroleum hydro- <br /> carbons greater than method detection limits(0.5 µg/L for individual constituents; l mg/L for <br /> TPH) were measured. <br /> 2.4 EA MONITORING WELL INSTALLATION <br /> IaFebraary-198'9`LA•itt'stalled fouradditiorial-'whoriitoring..wells-{EA]'<through?EA4)'at the-site <br /> perimeters to monitor any potential off-site movement of the hydrocarbon plume toward domes- <br /> tic wells (Figure 4). The well logs are included in Appendix A. During borehole drilling,soil <br /> samples were collected and analyzed for benzene,toluene,ethylbenzene,xylenes,and total <br /> petroleum hydrocarbons;the analytical results are included in Table 2. Groundwater from the <br /> new wells was sampled and analyzed for the same compounds,and these results are summarized <br /> in Table 3. <br /> 2.5 QUARTERLY GROUNDWATER MONITORING <br /> From 11 February 1988 until 22 March 1990, EA gauged the monitoring wells quarterly. Wells <br /> that were not dry and contained enough standing water were sampled, and the samples were <br /> Pnalyxed. Sufficient water to permit proper sampling was last present on 21 dune 1989. After <br /> that,all wells dried out due to the drought and increased usage of groundwater in Stockton area. <br /> A summary of quarterly gauging is in Table 5; a summary of groundwater analysis is in Table 3. <br /> c67/97780/tx 3 <br /> . J <br />