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Mr. Eric Jenks ` -3 - i 13 March 2000 <br />`r <br />The hydropunch investigation revealed a variety of constituents at concentrations exceeding water <br />quality objectives. GeoSyntec proposes to analyze the monitoring well groundwater samples for nitrate, <br />ammonia, volatile organic compounds, chlorinated herbicides, and fumigants. Since the grab <br />groundwater investigation also found organophosphate pesticides, atrazine, carbamate and urea <br />compounds, gasoline, diesel, and other hydrocarbons, the monitoring well analyzes should include these <br />constituents as well. <br />Atrazine may be analyzed by using EPA Method 619, or EPA Method 8141 using a nitrogen - <br />phosphorous detector. As I discussed in the site investigation portion of this letter, a groundwater <br />sample containing non -diesel hydrocarbons should be fingerprinted for identification. <br />GeoSyntec also proposes a water use and well survey of wells located within 2,000 feet of the facility. <br />GeoSyntec proposes to prepare a report describing the monitoring well installation, the sampling results, <br />the water use and well survey results, and recommendations for further delineation. <br />The work plan is approved subject to the following conditions: <br />Groundwater analyses shall include organophosphate pesticides, atrazine, carbamate and urea <br />compounds, gasoline, diesel, and other hydrocarbons, in addition to analyses for nitrate, <br />ammonia, volatile organic compounds, chlorinated herbicides, fumigants and general water <br />quality parameters as proposed in the work plan. <br />2. If JTF has not positively identified non -diesel hydrocarbon constituents in grab groundwater <br />samples, a monitoring well sample containing unidentified hydrocarbons shall be fingerprinted to <br />identify the compound. Only one such sample needs to be fingerprinted. <br />According to the schedule proposed in the workplan, a report describing the results will be prepared <br />within 15 weeks of receiving your written approval. The monitoring well installation report shall <br />include sample results from the storm drain discharge location. Based on this schedule, the report will <br />be due by 14 July 2000. <br />If you have an uestions, you may contact me at (916) 255-3080. <br />�y <br />AMY TERRELL <br />Site Cleanup Unit <br />cc: Ms. Lori Duncan, San Joaquin Public Health Services EHD, Stockton <br />Ms. Carolyn Kneiblher, GeoSyntec, Walnut Creek <br />