SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

STATE OF CALIFORNIA-Environmental Protect;agency PETE WILSON,Governor CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION °' 3443 Routier Road,Suite A Sacramento,CA 95827-3098 `;1Lzp ; PHONE:(916)255-3000 v (f FAX:(916)255-3015 A PR 2 U 1995 18 April 1995 ENVIRONMENTAL HEALTH PERMIT/SERVICES Mr. Nathan Esformes Triple E Produce Post Office Box 239 Tracy, CA 95378 GROUND WA TER REMEDIA TION A T TRIPLE E PROD UCE CORPORA TION, TRA CY, SAN JOAQUIN COUNTY I have reviewed the latest reports regarding the monitoring results and evaluation of the efforts to bioremediate the elevated levels of chloroform in ground water originating from the Triple E Produce Corporation in Tracy. These reports include the 6 February 1995 Progress and Quarterly Report submitted by PC Toxic, the 6 February 1995 Quarterly Groundwater Monitoring Report, Fourth Quarter 1994 submitted by AGRO Environmental Services, and the 9 February 1995 Assessment of Chloroform Genesis and Migration at the Triple E Produce Corporation Facility submitted by Condor Earth Technologies, Inc. (Condor). I disagree with the conclusions of the 6 February PC Toxic report that the chloroform concentrations in MW-7 have generally decreased. Chloroform concentrations in MW-7 have increased significantly since the well was first sampled in October 1992. The most significant increase in chloroform concentration in this well occurred between September and October 1994 when the concentrations increased from 10 µg/1 to 21 µg/1. Chloroform in MW-7 continued to increase to 28 µg/1 and 43 µg/1 in November and December 1994, respectively. The recent increase in chloroform in MW-7 occurred before the heavier than normal rains in early 1995, thus the increase is most likely due to liquid migration of the chloroform plume, rather than due to gas migration to the well in response to recent high intensity rainfall, as suggested in the 9 February 1995 Condor report. In that report Condor proposed to submit to the Board a ground water flow analysis and work plan for evaluation of gas phase transport within 30 days. We have not received this report. In my 6 July 1993 letter, I stated if chloroform concentrations increased in MW-7, we would require Triple E to install additional wells downgradient to determine the lateral extent of contamination. Due to the recent increases in chloroform in MW-7, Triple E is now required to complete characterization of the ground water contamination. In addition to defining the extent of ground water contamination, it is also necessary to prevent further migration of the plume. It is not necessary to wait for an evaluation of the effectiveness of the bioremediation before these activities occur since it is apparent that the plume is continuing to migrate beyond MW-7 in spite of the bioremediation being conducted at the source area.