SITE INFORMATION AND CORRESPONDENCE

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Ms. Nancy Bishop - 2 - 5 March 2003 ongoing monitoring of the HRCO pilot study. In the draft MRP,we have added the chlorinated herbicide suite of analyses (EPA 815 1) and toluene to the groundwater monitoring program for two operations area monitoring wells, as discussed further in the attached Memorandum. If these constituents are not detected for two consecutive monitoring events, they may be removed from the monitoring program for that well. Groundwater Monitoring Reports The groundwater monitoring reports include all the required information in a very readable format, although a few changes to the figures will improve the overall utility of the reports. Please add site features to the site maps, add the date that the pilot study began to the MW-2 graphical data summary, and maintain the same horizontal scale for all graphs on this data summary page. In the Second Quarter 2002 and in the Third Quarter 2002 Reports, the Geochemical Parameters Data Summary Table for HRC Pilot Scale Field Demonstration presented data obtained for MW-5 listed under the column heading of MW-4, and vice versus. GeoSyntec corrected this error in the 2002 Annual Report. The results tabulated for the analytes methane and carbon dioxide for monitoring well MW-5 during the 3 June 2002 sampling event are incorrect. The laboratory data sheets show that in MW-5 methane was detected at 0.006 mg/l, and carbon dioxide was detected at 3.74 mg/l. Please correct these entries in the next monitoring report. Soil Investigation As detailed in the attached Memorandum, the extent and nature of soil contaminants are sufficiently defined to proceed with the development of a cleanup plan with the exception of the rinse pad and stormwater ponding area in the northern area. The northern area is where the pilot study is underway, and soil characterization can be completed and associated remedial action can be developed after WFS evaluates the pilot study. Soil beneath the former tank farm needs to be remediated, and WFS needs to provide a schedule for a feasibility study, or a schedule for a cleanup plan, if it intends to excavate the material. Summary Please provide comments on the attached draft MRP and a schedule for a feasibility study or a cleanup plan for soils beneath the former tank farm by 15 April 2003, a date suggested by your consultant,Ms. Carolyn Kneiblher of GeoSyntec Consultants. If you have any questions, you may contact ea 916) 255-3080. UIQ � ti� AMY TERRELL Private Sites Cleanup Unit Enclosures (3) cc: Mr. Michael Infurna, San Joaquin County Environmental Health Department, Stockton Ms. Carolyn Kneiblher, GeoSyntec Consultants,Walnut Creek