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elevation contours estimated using the depth-to-water measurements collected on December 31, 1997 indlLated that groundwalcr tlow at the srtL was generally cons]StLnt with the estimated flow on September 18, 1997 On March 27 1998 Condor personnel were on SILL to conduct quarterly groundwater monitoring I aboratory ,malyses of groundwater Samples collected from the, site monitor wells indicated that BTEX, TPH-G and the sLlectcd gasoline oxygenates/additives were not detected at or above the laboratory reported detection limits in the sample collected from MW-1 Ltlianol, tertiary-butanol, DIPS, ETBE and TAME were not detected at or ' above the, laboratory reported detection limits in any of the groundwater samples Detection limas for the analysis of tHc tramples collected from MW-2 and MW-1 were, raised, however, due to rLlativcfy high concentrations of MI 13h in the sampIts collected from those wells (as described below) Benzene and I,PH-G I wLrL not CIOLLted at or above raised detection limits and low concentrations of rEX constituents were detected ui the ,anip[L col lccted trom MW-2 MTBF was detectLd at 110,000 ILg/l in the MW-2 sample B l FX and TPH-G were. not detected at or above,the laboratory reported detection limits in the sample collected from MW-3 MTBE ' was dLtcLtc,d at 1 900 �eg/l in the MWA sample IPH-(1 and BrFX constituents were detected in the sample collected from MW-4 M I BF was not detected at or above the laboratory reported deteLtlon limit In the MW-4 sampie No floating product sheen, or petroleum Hydrocarbon odor was noted in the monitor wells ' laboratory analytical results of the groundwater samples for the first quarter, 1998, monitoring event were generally consistent with historical quarterly groundwater analytical data M I'BE concentrations in samples from MW-2, howLve.r inLrcased by more than tv <) orders of magnitude, during the three sampling events conducted at the site I GroundwatLr elevation measurenlLnts collected at thL site monitor wells on March 27, 1998, indILated that the average depth from the. ground surface, to groundwater was approximately 5 1LLt Ilic average depth to water at the trite; increa',Ld by approximately 1 foot between December 31, 1997 and March 27, 1998 Groundwater elevation c.untours estimated using ihc, dLpth-to-water measurements collected on March 27, 1998, md]catLd that groundwatLr gradu.nt at the. site was gcnerall) e.onsIstent with the estimated gradient on September 18, 1997 and DLLLmbcr 31 1997 ' 1n a telephone convLr%dtion on March 23, 1998, Mr Ronald Rowe of the San Joaquin County Public Health Services/L,nvironmental Health Department (PHS/FIID) indicated that based on his review of the report dated December 11, 1997 (referenced above), he was requesting that quarterly groundwater monitoring continue. at the ' site FUrthLrmore, he requested that a work plan be prepared for conducting quarterly surface water sampling and additional invLstigation of the gasoline oxygenate/additive plume to the east of monitor well MW-2 Condor subsequently prtparcd the Wu1 k Plan Additional Soil and Gi oundxvater Inveingatuon / Surface Water ' Sampling dated May 27, 1998 In a faxed note dated June 1, 1998, Mr Rowe approved the work plan with the stipulation that a work plan addendum be prepared describing installation of additional borings to those proposed in the work plan and grab sampling of the Herman & Helen's Marina drinking water source Condor I subsequently prepared the Woik Plan Addondum, dated July 9, 1998 In a fax dated July 27, 1998, Mr Ron Rowe approvLd the work plan addendum adding that both the facility pre-treated drinking water and the post- treatment water should he sampled and analysed by appropriate methods On June 26, 1998, a C ondor representative was on site to conduct quarterly groundwater monitoring Laboratory analyses of groundwater samples collected from the site monitor wells indicated that BTEX, TPH-G and the ~elected gasoline oxygenates/additives were not detected at or above the laboratory reported detection limits in the sample collected from MW-I Ethanol., tertiary-butanol, DIPS, and ETBE were not detected at or above the laboratory reported detection In-nits in any of the groundwater samples TAME was detected in the samples collected from MW-2 and MW-3 M I'BE was detLLtLd in the samples collected from MW-2, MW-3, and MW-4 BTEX and TPH-G were not detected at or above. raised laboratory detection limits in the samples collected from MW-2 and MW-3 Relatively low concentrations of benzene, ethyl benzene, total xylenes, and TPH-G were detected in the sample collected from MW-4 Toluene was not detected at or above a raised laboratory detection