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Geo(agrea(Tecknus Inc Page 5 <br /> Groundwater Monitonng Report <br /> Project No 724 2 <br /> October 3,2002 <br /> ' screened intervals of these wells (55-60 feet bgs) are placed near the elevation of the <br /> groundwater table in 1992—approximately 54 feet bgs <br /> ' indicated i Figure — W- TPH- vs GW Elevation with the exception of June 20 <br /> As dicate n P gu e 9 M 2 G , p , <br /> ' 1997, contaminant concentrations have been stable in down gradient well MW-2 <br /> Oxidation/Reduction Potential (ORP) measurements (Table 5) show that wells MW-4, MW- <br /> ' 5 and MW-6 have positive values The negative ORP values observed in the rest of the <br /> wells show that they are either within the core of the contamination plume or are in the <br /> reaction/depletion shadow down gradient of the plume <br /> As required under AB2886, the laboratory data was submitted electronically to GeoTracker <br /> on September 11, 2002 - confirmation number 1307958364 <br /> ' Two previous GeoTracker submittals (3`d and 4"' Quarters 2001) were rejected due to <br /> incorrect values The Yd quarter 2001 report had incorrect values of TPH-G for MW-106 <br /> ' The electronic copy was corrected and resubmitted on October 2, 2002 — confirmation <br /> number 6161538422 The 4th quarter 2001 report had an incorrect MTBE value for MW-7 <br /> in GTI's data table submitted with the report The value was corrected and is included in <br /> this report The original electronic data was resubmitted on October 2, 2002 — confirmation <br /> number 7904575705 <br /> 3 0 CONCLUSIONS &RECOMMENDATIONS <br /> ' The contamination plume as observed from these wells is stable and does not appear to be <br /> sourcing a significant off site plume In GTI's opinion the levels of contamination present <br /> do not warrant an engineered clean up But in their correspondence dated April 24, 2002, <br /> the San Joaquin County Environmental Health Department (SJC/EHD) directed the <br /> submittal of a work plan for additional lateral plume definition GTI prepared this work <br /> ' plan on June 27, 2002 On September 3, 2002, Mr Nuel Henderson of SJC/EHD issued a <br /> letter requesting modifications to the work plan On September 25, 2002, GTI submitted a <br /> letter modifying the June 27, 2002 work plan <br />�1 <br />