SITE INFORMATION AND CORRESPONDENCE

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California Reinal Water Qualit o p�-Board Central Valle Region `, 'l v Y g L� Robert Schneider Chair Terry Tamminen Sacramento Main Office Arnold Schwarzenegger Secretary for Internet Address: http://www.swrcb.ca.gov/rwq"VIRUNIVILIVT HEALTH Governor Environmental 11020 Sun Center Drive#200 Rancho Cordova,CA 9567 Protection Phone(916)464-3291 Fax(916)464-4797 IT/SERVICES 19 August 2004 Mr. Arnold Hof 28537 E. River Road Escalon, CA 95320 TRANSMITTAL OF MONITORING AND REPORTING PROGRAM NO. R5-2004-0805, FORMER CAL FARMSUPPLY, 2040 WEST WASHINGTON STREET, STOCKTON, SANJOAQUIN COUNTY Central Valley Regional Water Quality Control Board(Regional Board) staff reviewed the 6 May 2004 Groundwater Monitoring Report(GMR)prepared by Karsyn Environmental Ltd. (Karsyn) for the former Cal Farm Supply site at 2040 West Washington Street in Stockton. The GMR contains a summary of the site history,presents groundwater quality data, evaluates the status of the remediation system, and proposes changes to the draft Monitoring and Reporting Program. Monitoring and Reporting Program No. R5-2004-0805 On 30 April 2003, we transmitted a draft Monitoring and Reporting Program (draft MRP) to you, which proposed reducing the monitoring frequency to annually, and removing some wells from the sampling schedule since they do not contain constituents of concern In the GMR, Karsyn requests that analyses for ammonium be removed from the MRP since it is only occasionally detected at concentrations below the water quality goal of 0.15 mg/L. We concur and removed ammonium from the MRP. Karsyn also requests that the fuel consituents total petroleum hydrocarbons as gasoline (TPH-g), benzene, and MTBE be removed from the monitoring schedule due to declining concentrations in the related monitoring wells. We do not concur, since it is the declining concentrations that identify when the site is eligible to be considered for No Further Action(NFA). The groundwater cleanup goal for TPH-g is 5 ug/l,but since the method detection limit is 50 ug/l, this becomes practical cleanup goal. Similarly, Karsyn requested that benzene hexachloride be removed from the schedule for MW-3. Regional Board staff can consider a NFA request when the monitoring well data show that these constituents are no longer of concern. Without the data, that determination cannot be made. Therefore, you need to monitor for these constituents at least annually in their respective wells. Karsyn also observes that concentrations of all constituents have been steadily declining and that the site soon will be ready for NFA evaluation. Nitrate has declined dramatically in the past two years, and fuel California Environmental Protection Agency p�a Recycled Paper