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Ms.Patricia Sullivan <br /> Page 2 <br /> July 1, 1996 <br /> even though Hydropunch results for MW-22 indicated PNAs and lampblack <br /> was found in shallow soils at MW-23R. The decision was made to install the <br /> Zone B wells in those locations rather than on EI Dorado Street so that the <br /> wells could be closer to the former MGP and because there are historic <br /> petroleum-related sites upgradient of Area H. This information was <br /> provided by Linda Turkatte of San Joaquin County Health. <br /> Based on results from the new wells,the extent of PNAs in Zone B has been <br /> confirmed beneath Area I. PNAs were also detected in Zone B in Area IL <br /> PNA concentrations in Zone B have been similar upgradient as well as <br /> downgradient of Area I. The highest PNA and BTEX concentrations in Zone <br /> C have been found in MW-16,a cross-gradient well,located near historic <br /> service stations. The extent of benzene has been defined as beneath Area I <br /> within Zones A,B, and C. <br /> Fernando asked if we have enough information to compile the FS since we <br /> havenot found the extent of PNAs in Zone B. Paula responded that because <br /> there are very limited locations for drilling new wells in Area II,it does not <br /> make sense to drill in Area II at this time to try to further define <br /> groundwater. Patricia also said that we need at least four quarters of <br /> groundwater data to delineate PNAs in the new B Zone wells,and that <br /> PG&E will assume a nondetect line for PNAs in Zone B for the purpose of <br /> evaluating alternatives in the FS. It was decided that this assumption would <br /> be included in the final responses to comments on the Phase IV report. <br /> Philip said that he did not agree that Zone C concentrations have been <br /> defined since he believes that the gradient in Zone C may have been different <br /> historically. Paula stated that PNAs in well MW-16 could be due to the <br /> historic service stations located near this well since PNAs are found in diesel. <br /> Philip asked which PNAs are found in diesel. Paula said that CH2M HILL <br /> would distribute information on which PNAs are found in diesel. <br /> Fran said that PG&E should substantiate the existence of other sources (e.g. <br /> through Hydropunch samples). Patricia stated that PG&E is not in the <br /> position to drill on other properties.Tricia asked Philip if he would provide <br /> information on other nearby sites because PG&E and CH2M HILL are aware <br /> that there have been and there exist petroleum and PNA-related release sites <br /> such as the Port of Stockton and McCormick and Baxter and that PG&E is not <br /> the only source in this area. <br /> C. Paula Bolio reviewed the conclusions that are made following results of <br /> previous investigations as well as the Phase rV investigation. The <br />