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< i <br /> MONITORING WELL SAMPLE EVENT OF 3/13/2001 <br /> . Sampling Procedure <br /> Monitoring wells were vented and purged by normal methods per standards of the industry (see <br /> Groundwater Field Report by Del-Tech Geotechnical Services attached). Purge pump rates were+/-0.2 <br /> gallons per minute in all monitoring wells. Groundwater samples were extracted from each monitoring <br /> well using the check valve in tube technique. Samples were transported on ice for delivery under chain <br /> of custody to GeoAanalytical Laboratories for analysis. <br /> Sample Analysis <br /> Water samples were analyzed by EPA methods 8021 B for BTEX, 5030/Luft for TPHg, and EPA 8260B <br /> for Oxygenates. Results of all sample analyses are attached in the original form and in recap form. <br /> Findings From Water Sample Analysis <br /> BTEX and TPHg levels remain within the same range for GMX-1 and MW-2 as the last sampling event. <br /> The water samples taken from GMX-1, and MW-3 contained low levels of MTBE and tert-Butanol <br /> ranging from 42 ug/L to 100 ug/L. The highest concentrations of MTBE and tert Butanol have shifted <br /> from GMX-1 down gradient to MW-3. <br /> The groundwater surface has raised about +/- 1.7 from the last event (see Del-Tech Field Report <br /> attached). The groundwater gradient continues to have a down slope gradient to the southeast at 5=0.002. <br /> Conclusions <br /> The water sample analysis from monitoring well GMX-1 indicates lower concentrations of BTEX,TPHg <br /> and TERT-BUT compared to the 08/29/2000 sampling event. Oxygenates are present in GMX-1,MW-3 <br /> in low concentrations.This is the first sampling event that produced non-detect for all oxygenates in MW- <br /> 4. The water surface in all of the monitoring wells has lowered about two feet from March of last year. <br /> This sampling event occurred at a time of the year with the lowest demand for domestic and agricultural <br /> irrigation. <br /> Recommendations <br /> As in the last event report,it is recommended that the installation of a groundwater reclamation system <br /> begin before the proposed start of property development. As of the date of this report, a reclamation <br /> system has not been installed. Quarterly groundwater monitoring should continue. <br /> Please contact Ervin Rifenburg of this office (2091368-9381) if any questions arise concerning this <br /> Report. <br /> Respectfully submitted, �ROFEBB/o <br /> RIFE&,# A-c <br /> Fo i eerin <br /> m <br /> No. 1 5 M <br /> Exp. <br /> Ervin Rif C <br /> " rOF r.-N.lw�a <br /> • cc: Diana Maragos, Attorney for° `un West Liquors <br /> cc: W. T. Mitchell Group <br /> 2 <br />