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MONITORING WELL SAMPLE EVENT OF 6/26/01 Sampling Procedure Monitoring wells were vented and purged by normal methods per standards ofthe industry(see Groundwater Field Report by Del-Tech Geotechnical Services attached).Purge pump rates were+/-0.2 gallons per minute in all monitoring wells.Groundwater samples were extracted from each monitoring well using the check valve in tube technique. Samples were transported on ice for delivery under chain of custody to GeoAanalytical Laboratories for analysis. Sample Analysis Water samples were analyzed by EPA methods 8021B for BTEX, 5030/Luft for TPHg,and EPA 8260B for Oxygenates.Results of all sample analyses are attached in the original laboratory form and in recap form. Findings From Water Sample Analysis The sample from monitoring well MW-3 is the only sample that produced a detectable amount of Oxygenates present. BTEX and TPHg levels remain within the same range for GMX-1 and MW-2 as the last sampling event.The water samples taken from MW-3 and MW-4 were non-detect for both BTEX and TPHg.This is the first quarter that GMX-1 has not been above detection levels for Oxygenates. The groundwater surface has lowered about+/-2.4'from the last event(see Del-Tech Field Report enclosed). The groundwater hydraulic gradient has changed direction from southeast to south at a slope of S=0.002. Conclusions A major lowering of MTBE levels has occurred with these lower groundwater table elevation and are the lowest ever found on this site. The water sample analysis from monitoring well GMX-1 and MW-2 continue to produce analysis for TPHg around 22 mg1L, the same as the last sampling event. The more soluble Oxygenate compounds may be reaching higher dilution levels with the drop in groundwater table elevation. The less soluble TPHg compounds have remained at the same concentration levels for the last three Quarters. Recommendations As in the last event report,it is recommended that the installation of a groundwater reclamation system begin before the finish ofthe current property development.As ofthe date ofthis report,preapproval for the first step in a reclamation system has not been given by the UST fund. Quarterly groundwater monitoring should continue. Please contact Ervin Rifenburg of this office(209/368-9381)if any questions arise concerning this Report. Respectfully submitted, dap%0FfsS/t�, , RIF Foot gmeerin a� Ervin ltifenbur CE cc: Diana Maragos, Attorney for s 'Liquors . cc: W. T. Mitchell Group 2