ARCHIVED REPORTS XR0004079 - Laserfiche WebLink

Home Browse Search

Performed a quarterly groundwater monitoring event. Marcel Delacruz of the Caltrans was notified of the monitoring event on December 12, 2002, as required by Caltrans Permit No.1002-6NV-0218. Monitoring wells were vented and purged by standard of the industry methods(see Groundwater Field Report by Del-Tech Geotechnical Services, attached). Purge rates were 0.5 gal/min. Groundwater samples were extracted from each monitoring well using the Watera Inertia Pump technique with dedicated sample tubes. Samples were transported on ice for delivery under chain of custody to GeoAanalytical Laboratories for analysis. The new extraction well was also sampled and that sample analysis is part of this report. Sample Analysis Water samples were analyzed by EPA methods 8021B for BTEX,5030/Luft for TPHg,and EPA 8260B for Oxygenates. At the request ofEHD 1,2-DCA and EDB were also analyzed by EPA method 8062B. Results of all sample analyses are attached in the original laboratory form and also in recap form. Findings From Water Sample Analysis The plume concentration has changed from the last sampling event.MTBE concentrations in monitoring well GMX-1 have raised from non-detect on the last event to 23 ug/L on this event. The only monitoring well above the non-detect level for MTBE was GMX-1. The major changes in TPHg has occurred in extraction well GMX-1 with TPHg dropping from 20 mg/L to 5.9 mg/L. GMX-1 also,was analyzed to contain 175 ug/L of Tert-Butanol. The groundwater surface has raised about +/- 2' from the last event (see Del-Tech Field Report, enclosed). The groundwater hydraulic gradient is to the southeast at a slope of 5 .002. • Conclusions MTBE above detectable levels only occurred in monitoring well GNIX-1. Groundwater elevations have risen from the last event about two feet, which is very similar to the same quarter last year. The water sample analysis for monitoring well GMX-1,MW-2 and the extraction well EW-1 continue to produce low levels of TPHg(see Water Sample Analysis Recap attached). Recommendations And Work in Progress Quarterly groundwater monitoring should continue as in the past.A Final Remedial Plan has been mailed to your office that recommends a"Pump and Treat"reclamation plan for the contaminated groundwater. A preapproval request for funding for the installation of a CPT to 75'is in the hands of the UST Cleanup Fund. Planning for the installation will begin when funds are granted. Please contact Ervin Rifenburg of this office (209/368-9381) if any questions arise concerning this Report. Respectfully submitted, ��P ` VkVEp��9 Foot n eenn _ LU W.1975 rrt Ervin Ri e cc: Diana Maragos, Attorney for Sun est Liquors, W. T. Mitchell Group 2