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78 feet on March 3, 2003. Three samples of soil and three samples of the groundwater were extracted <br /> and analyzed. All CPT soil and groundwater samples were analyzed as non-detect. <br /> MONITORING WELL SAMPLE EVENT OF 12/10/02 FINDINGS AND RECOMMENDATIONS <br /> Sampling Procedure <br /> On March 27, 2003, Det-Tech Geotechnical Services, under the supervision of Foothill Engineering <br /> performed a quarterly groundwater monitoring event. Marcel Delacruz of the Caltrans was notified of <br /> the monitoring event on March 25, 2003, as required by Caltrans Permit No.1002-6NV-0218. All <br /> monitoring wells were vented and purged by standard of the industry methods(see Groundwater Field <br /> Report by Del-Tech Geotechnical Services, attached). Purge rates were 0.5 gal/min. Groundwater <br /> samples were extracted from each monitoring well using the Watera Inertia Pump technique with <br /> dedicated sample tubes. Samples were transported on ice for delivery under chain of custody to <br /> GeoAanalytical Laboratories for analysis. The extraction well,EW-1,was also sampled and that sample <br /> analysis is part of this report. <br /> Sample Analysis <br /> Water samples were analyzed by EPA methods 802113 for BTEX,5030/Luft for TPHg,and EPA 8260B <br /> for Oxygenates. At the request of EHD 1,2-DCA and EDB were also analyzed by EPA method 8062B. <br /> Results of all sample analyses are attached in the original laboratory form and also in recap form (See <br /> Water Sample Analysis Recap attached). <br /> Findings From Water Sample Analysis <br /> The plume concentration has changed from the last sampling event.MTBE concentrations in monitoring <br /> well GMX-1 have lowered from 23 ug/L on the last event to14 ug/L, while TPHg raised to 10 mg/L on <br /> this event. The only monitoring wells above the non-detect level for MTBE were GMX-1 and MW-3. <br /> The concentrations of TPHg in wells GMX-1,MW-3 and EW-1 have nearly doubled for this sampling <br /> event. <br /> The groundwater surface has raised about +/- 17 from the last event (see Del-Tech Field Report, <br /> enclosed). The groundwater hydraulic gradient is to the southeast at a slope of S=0.001. <br /> Conclusions <br /> MTBE above detectable levels only occurred in monitoring wells GMX-1 and MW-3 and at rates less <br /> than 15 ppb. Groundwater elevations have risen from the last event about two feet, which is about one <br /> foot lower than the same quarter last year. The water sample analysis for monitoring well GMX-1,MW- <br /> 2 and the extraction well EW-1 continue to produce low levels of TPHg(see Water Sample Analysis <br /> Recap attached). The natural attenuation of all analytes continues at 10%to 20%per year due in part to <br /> the yearly groundwater elevation cycles. <br /> Recommendations and Work in Progress <br /> Quarterly groundwater monitoring should continue as in the past.A Final Remedial Plan has been mailed <br /> to your office that recommends a"Pump and Treat"reclamation plan for the contaminated groundwater. <br /> The CPT work your office requested has been completed and a report issued by this office. Early action <br /> is requested on the"Pump and Treat"work plan for the groundwater reclamation of this site.Concurrence <br /> by the lead agency with the "Pump and Treat"reclamation plan is required before the UST Fund will <br /> grant a request for preapproval of reimbursements funds. <br /> 2 <br />