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Ms Lori Duncan <br /> Page 3 of 3 <br /> SUMMARY <br /> Groundwater levels and the direction of groundwater flow beneath the site were generally consistent with <br /> historical measurements An average of 0 26 feet of free product was measured in well MW3 during the <br /> reporting period, although the measured thickness has been steadily declining since Ground Zero initiated a <br /> program of regular product bailing from the well No petroleum hydrocarbon constituents have been <br /> detected in any of the other site wells (MWl, MW2, MW4) PCE and chloroform were detected in well <br /> MWI, MW2, and MW4, however The concentrations of PCE in groundwater samples collected during <br /> this sampling event ranged from 17 ppb to 24 ppb, which exceed the primary MCL of 5 0 ppb <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> Petroleum hydrocarbon contamination is apparent in groundwater within close proximity to the former UST <br /> Neither free product nor the dissolved petroleum hydrocarbon plume extends to perimeter wells, however <br /> The perimeter wells are located approximately 20 feet southwest, 35 feet north, and 40 feet northeast of the <br /> former UST PCE concentrations in groundwater remain above the primary MCL <br /> Based upon the groundwater data collected to date, Ground Zero recommends continuing periodic free <br /> product removal from well MW3 In correspondence dated April 16, 2002, the San Joaquin County <br /> Environmental Health Department (EHD) approved the April 4, 2002 workplan to further investigate <br /> the lateral extent of the VOC contaminant plume and requested a revised workplan to address the <br /> vertical extent of contamination and potential feasibility testing A revised workplan will be submitted <br /> • under separate cover <br /> The next monitoring and sampling event is scheduled for June 2002 Ground Zero will provide a minimum <br /> of 48 hours notice to EHD prior to conducting any fieldwork <br /> Please feel free to contact John Lane of Ground Zero at(209) 838-9888 if you have any questions regarding <br /> this submittal <br /> D GAO <br /> Respectfully, <br /> Ground Zer Analysis, Inc �tv� .10!'N P <br /> o L;Nc <br /> No 6795 <br /> Jo P Lane cls, 4 <br /> CA Registered Geologist No 6795 <br /> F OF CP�-1�C3 � <br /> Attachments <br /> cc Mr Gary Gabbard <br /> Mr Patrick Riddle, Attorney at Law <br /> Mr Marty Hartzell, RWQCB-Central Valley Region <br /> G\DaSa1GROi]NDZEIGP.$BARDlreports11QM2002 doc <br />