SITE INFORMATION AND CORRESPONDENCE_FILE 2

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October 15, 2003 a meeting was held at the San. Joaquin County Environmental Health office to discuss necessity for ground water remediation. The following participated: Mr. Harlan Knoll, Mr. Noel Henderson's Margaret Liguria Mr. Bill Little, AGE consultant Mr. Brian Newman / Mr. James Barton, State Water Resources Control Board. (Central Valley Region) Not invited was Russell F. Chapin (property owner) At this meeting a directive was adopted to perform an operation hiatus the ground water extraction and treatment system the extraction system operation suspend after October 18 2003 sampling. The following items were discussed during the October 15 2003 meeting: I The ground water pump-and-treat system continuously operated at the site for one and a half years Over this time period approximately three million_gallons of impacted water have been treated. Cumulative totals of Benzene and TPH-g were also discussed at the meeting. 2 Continuous concentration has been reduced when compared in pre- remediation levels at most impacted ground water monitoring wells. The disposition of the remaining soil contamination under the building at the site was discussed It was generally agreed that remaining soil was the source of residual contamination documented in the extraction well water samples Subsequently, an assessment and mitigation of the soil contamination under the building by soil vapor extraction or if feasible established by soil excavation would be required. 4 The continual removal of ground water was not concurred by the Board. The Board indicated that soil vapor extraction was the most effective measure to remove contamination from the site over and compared to the ground water extraction The Board recognized the need to remove contamination within the saturated zone possibly utilizing duel-phase extraction of both soil vapor and ground water. However the Board recommended a soil vapor extraction rebound pilot study, along with additional soil vapor or soil sampling under the subject building. The Board also recommended a ground water extraction "hiatus". The groundwater extraction system will be shut down for thirty- days to determine if an increasing concentration would be observed. Sampling prior to the hiatus would be required to evaluate changes in concentration. 6 The Environmental Health Dept advised that a mass calculation of the pre ground water extraction process should be generated, allow for a mass percentage removal-analysis by the SVE and ground water extraction system.