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MONITORING WELL SAMPLE EVENT OF 12/22/2000 <br /> Ole 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+1-0.5 <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 /> Contamination of BTEX and TPHg in low concentrations was found in the water of monitoring wells <br /> MW42 and GMX-1. The water samples taken from GMX-1,MW-3,and MW-4 contained low levels of <br /> MTBE ranging L to 73 ug/L. Tertiary-butanol was non-detect in all the monitoring wells, <br /> g g frown 1.0 u� <br /> which is a considerable drop from the last event. <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 /> and MW-4 in low concentrations. The water surface in all of the monitoring wells has raised one foot <br /> from the last monitoring event. The direction of the hydraulic gradient is to the Southeast with a slope <br /> of S=0.002. This event occurred at a time of the year with the lowest demand for agricultural irrigation. <br /> This may account for the rise in groundwater elevation. <br /> Recommendations <br /> The last event report recommended the installation of a groundwater reclamation system before the <br /> proposed start of property development. As of the date of this report,a reclamation system has not been <br /> installed.It is recommended by this author that a groundwater reclamation system be installed before any <br /> development starts on the property. Quarterly groundwater monitoring should continue. <br /> Please contact Ervin Rifenburg of this office (209/368-9381) if any questions arise concerning this <br /> Report. <br /> Respectfully submitted, <br /> RIFC.0 rn <br /> �keO t <br /> Foothil ineen <br /> No.187 <br /> Exp. <br /> Ervin Ri n ur , R OFC <br /> cc: Diana Maragos, Attorney for Sun West Liquors <br /> cc: W. T. Mitchell Group <br /> 2 <br />