SITE INFORMATION AND CORRESPONDENCE

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W.T.Nickerson April 23, 1997 Page 2 A third location listed in Item 2.of the 12 March letter was the PureGro Tank Farm. It was agreed to interview Mr. Mercer as to where the old tank farm was located, and what products were handled. You requested the 1995 soil sampling data that Wendy had referred to in her 12 March letter and she agreed to provide us with all she has. A soil investigation would be done in any areas of concern related to the former tank farm. A fourth location in Item 2. of the 12 March letter was the wash rack area. Wendy asked that Unocal collect soil samples in areas surrounding the wash rack. She also wants a narrative from Mr. Mercer as to how long it has been there, and some discussion of any previous problems, etc. Another item Wendy had inquired about was how ethylene dibromide (EDB) and dibromochloropropane (DBCP)were handled on the site. She wants to know if PureGro handled these chemicals in bulk. She also asked if PureGro had another wash rack in the past. She asked how the EDB and DBCP got into the former pond area soils. These questions all are to be addressed in a proposed interview with Bob Mercer. The next item of discussion was the requested human health risk assessment. You expressed concerns regarding the scoping of this task. Wendy asked us to review all the data tables, and to submit for her review a human health risk assessment work plan prior to submittal of the proposed scope of work to DTSC reviewers. She stressed that all the Regional Water Quality Control Boards (state-wide) have a memorandum of understanding with DTSC and other state agencies to the effect that the regional boards have regulatory oversight for ag-chem facilities in California, and that they (CVRWQCB)would therefore be the lead agency in this risk assessment work, including both soil and ground water. Rudy Schnagl backed up this statement. Jan Wagoner asked if there was a screening level for nitrogen in soil. Wendy said she would look this up. You stated that you would be leaning toward utilizing DTSC (rather than OEHHA) for oversight on the risk assessment. Wendy said she would provide to you the name of the person who will act as the point-of-contact at DTSC for this work, and she will also provide a sample contract for retaining DTSC in this capacity. RWQCB cannot contract with DTSC directly. Wendy urged that we stick to the approved work plan in doing the risk assessment, as other groups have not fared well in deviating from the approved work plan. Wendy is deciding whether to issue a letter notifying San Joaquin County Public Health Department about the recent detection of DBCP in our down-gradient wells. She also stated that the hits on 1,2-DCP and DBCP in MW-9 (in her samples and ours) indicated the need for a well farther down-gradient. You then asked how many more wells would be considered sufficient, and how far down-gradient to go? Rudy suggested that we formulate an opinion on this issue in the upcoming quarterly monitoring report. We shall do so. Four action items were discussed: 1) Sierra-Pacific to complete a written response to RWQCB comments on the 1,2-DCP report, 2) Sierra-Pacific to schedule an interview session with Bob Mercer of Western Farm Service, 3) Sierra-Pacific to prepare a letter indicating the proposed schedule for completion of the tasks listed in the 12 March letter from RWQCB to Unocal, and 4) Sierra-Pacific to complete a work plan for all the work discussed in this meeting and the 12 March letter.