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4 SUMMARY OF FINDINGS AND RECOMMENDATIONS <br /> A summary of current groundwater conditions and PSC's recommendations are <br /> contained in the following sections <br /> 4.1 Groundwater Conditions <br /> PSC's data from this current monitoring event and from previous assessments <br /> indicates that the highest concentrations of petroleum hydrocarbon <br /> compounds are centered in the vicinity of the former gasoline USTs near well <br /> SP-1 Since the installation of new air sparging well SP-A, petroleum <br /> hydrocarbon concentrations in site monitoring well groundwater samples have <br /> decreased significantly <br /> The plume of groundwater impacted with detectable hydrocarbons appears to <br /> have decreased since the installation of sparging well SP-A This plume may <br /> be less than 150 feet wide and 300 feet long, elongated in the same east- <br /> northeast direction as groundwater flow <br /> Oxygenates concentrations have also displayed a reduction since the <br /> installation of sparging well SP-A D1PE has been detected in samples <br /> collected from wells close to the source Oxygenate compounds MTBE and <br /> TBA observed this quarter are considered to be potentially anomalous <br /> PSC recommends continuation of routine groundwater monitoring to assess <br /> evolving subsurface conditions at the Earthgrains facility For the next round <br /> of monitoring, scheduled in February 2003, PSC intends to collect <br /> groundwater samples from all of the site monitoring wells to evaluate <br /> conditions <br /> 4.2 Remedial Recommendations <br /> Groundwater sample and air vapor analytical results suggest that the air <br /> sparging and venting remedial operations has proved successful in removing <br /> dissolved phase gasoline contaminants in soil and groundwater However, the <br /> remedial system's effectiveness at continued contaminant removal may be <br /> near an end PSC intends to disengage the system from December to at least <br /> the next round of groundwater monitoring scheduled in February 2003 to <br /> assess whether contaminant concentrations fluctuate <br /> r Il <br /> November 2002 Groundwater Monitoring And Remediation Status Report <br /> The Earthgrams Baking Company <br /> 265E South Airport Way-Stockton,California <br /> Prepared Cor l i]E EARIIICRA1NS BAKING CONIPANY Prepared by Philip Services Corp <br /> If 1ENV\62400132\121382fG\Slockton\Stocklon1I 102mon doc ©ecembcr 9 2002 <br />