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r STATE OF CALIFORNIA-Environmental Protec�gency PETE WILSON,Governor CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION a 3443 Routier Road,Suite A Sacramento,CA 95827-3098 PHONE:(916)255-3000 FAX:(916)255-3015 14 May 1996 Mr. Verrill Norwood, Vice President Pioneer Americas, Inc. 116 Sunburst Lane, N.W. Cleveland, TN 37312 WORK PLAN FOR SOIL AND GROUND WATER INVESTIGATION, ALL PURE CHEMICAL COMPANY, TRACY, SAN JOQUIN COUNTY I have reviewed the 29 April 1996 Work Plan for Soil and Ground Water Investigation submitted for the All Pure Chemical Company at 26700 S. Banta Road. The work plan is inadequate and does not address the objectives of determining the lateral and vertical extent of ground water contamination. It also does not include the pumping history of the two onsite production wells as requested in my 22 January 1996 letter. The three proposed monitoring wells will not provide information on the lateral extent of volatile organic compounds (VOCs) in ground water to the northeast, the direction of the regional ground water flow. It is necessary to obtain this information to determine if VOCs have already migrated offsite and will be pulled to the north by the ground water extraction system to be installed at the Tracy Defense Depot this fall. As discussed in my 22 January 1996 letter, there is already evidence that VOCs have migrated from All Pure to the northeast. Investigation of ground water offsite of the All Pure facility is necessary to determine the lateral extent of VOCs to the north-northeast, east, and south-southeast of the All Pure facility. The proposed monitoring wells also will not determine the vertical extent of ground water contamination. Investigation of the ground water at depths deeper than the existing monitoring wells is needed to assess the vertical extent of VOCs in ground water. The work plan includes a closure plan for the ponds. We did not request this in either our 22 January 1996 or 20 March 1996 letters. We have just completed our review of the closure plan submitted in July 1994. You should have received our comments on that plan by now. The proposal for closure of the ponds in the April 1996 work plan is different from that proposed in the 1994 plan. The main differences are in the analyses to be performed on the soil samples, the ponds to be closed, and the soil sampling methodology. I have commented on the analyses to be performed and the ponds to be closed in my 9 May 1996 letter. Below are my comments on the soil sampling methodology proposed in the April 1996 plan.