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STATE OF CALIFCRNIA-Environmental Protection AbwCy tir PETE WLSON,Govemor CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION 3443 Routier Road,Sufte A —_— Sacramento,CA 95827-3098 PHONE:(916)255-3000 FAX:(916)255-3015 19 September 1995 Mr. Nathan Esformes Triple E Produce P.O. Box 239 Tracy, CA 95378 GROUND WATER INVESTIGATION AND REMEDIATION, TRIPLE E PRODUCE, TRACY, SAN JOAQUIN COUNTY I have reviewed the 10 August and 15 August 1995 letters regarding the cost analysis of extracting ground water from MW-7 and addendum to the revised work plan, respectively, for the Triple E Produce facility in Tracy. Cost Analysis of Extracting Ground Water from MW-7 Triple E agreed at our 7 July 1995 meeting to conduct a cost analysis of extracting ground water from MW-7 at a low rate, if necessary, to achieve capture of the known extent of chloroform. It was not decided at the meeting to use this well for extraction, but simply to evaluate the cost of doing so. Your 10 August letter goes against this agreement. This analysis is still needed, since this well may need to be used to achieve full containment. Along with the cost analysis, Triple E needs to submit capture zone maps corroborating its statements that the extraction scenario (20 gpm at XW-1 and five gpm at MW- 4A) will capture the plume beyond MW-7. By 18 October 1995, you shall submit a report including the cost analysis and capture zone analysis. Addendum to Revised Work Plan Alternative to MW4A Increasing the pumping rate of XW-1 to compensate for the loss of MW4A, should MW4A not be able to sustain a five gpm pumping rate after redevelopment, is not the most efficient way to remediate the ground water. Removal of the higher levels of chloroform from MW4A is more efficient than pulling the high levels of chloroform near MW4A over 1,000 feet downgradient to be extracted from XW-1. It is preferable to replace MW4A with a well which could sustain the 5 gpm pumping rate, if MW4A cannot sustain this rate. Details of Construction and Development of XW-1 Triple E needs to present the rationale for using 45 mg/kg chloroform as the level to determine if cuttings should be removed to a landfill and idenify the "appropriate locations on site" for disposal of soil containing chloroform at concentrations below 45 mg/kg.