SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Mr. Ken Gillies Gillies Trucking 3931 Newton Road, Stockton Page 4 of 6 impacted groundwater, you are hereby directed to destroy the well within 90 days from the date of this letter. This directive and your compliance with it are not contingent on reimbursement of destruction and replacement costs by the State Cleanup Fund. Failure to comply with this directive in this time frame may result in a request for enforcement action either through the San Joaquin County District Attorneys Office or the CVWQCB. It should also be noted that during a phone call with your consultant on 04 December 2003, the EHD noted that the report of findings for the December 2003 CPT investigation should include an estimate of the sorbed contaminant mass in the Modesto Formation, the effects of the Gillies well (G-1) on the contaminant plume, and a fate and transport model for contaminants should groundwater rise into the Modesto Formation again. These items were not addressed in the report of findings included in Fourth Quarter 2003 Report. The EHD cannot concur with your request for closure consideration at this time and has discussed the issue with the Central Valley Regional Water Quality Control Board (CVRWQCB) representative, who agrees with the EHD decisions and directives. The EHD cannot concur with closure of the site at this time for the following reasons: 1. The lateral extent of impacted groundwater in the three sand units has not been fully delineated as discussed above. 2. The vertical extent of impacted groundwater has not been fully delineated. In fact, contaminant concentrations appear to be higher in the deepest sample obtained at 115 feet bsg in CPT-1 than in the sample collected from 80 feet bsg. 3. Diesel contaminants were detected in the shallow water sample from CPT-2 placed near the domestic well, but deeper water samples were not collected and/or analyzed so it is not known if the deeper groundwater has higher contaminant concentrations, therefore the vertical extent of impacted groundwater near the domestic well has not been delineated. 4. An as-built well diagram and/or drillers log or video survey for the Gillies domestic well has not been provided to the EHD despite previous requests and your agreement to provide such a video, and despite the EHD approval of your 22 January 2003 work plan to conduct the down- hole video surveys of the Gillies and Barbot domestic water wells. With no information on the well design or geology, it is difficult to infer the potential future effect the well will have on impacted groundwater and vice versa. As noted by UEC in a previous report, there are over 30 domestic wells within 2000 feet of the site, some shallow, many without known designs. The shallow groundwater in this area is an important groundwater resource that must be protected.