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23 October 1995 <br />' AGE-NC Protect No 95-0104 <br /> Page 3 of 5 <br />' 3 2 GROUND WATER SAMPLING <br /> Monitoring wells MW-1 through MW-4 were purged and allowed to recover for a muumum of one <br /> hour prior to sample collection Water samples were collected from MW-I through MW-4 utilizing <br /> a dedicated, disposable polyethylene bailer and new nylon rope Sufficient sample was collected from <br /> each well to fill three 40-m1 EPA vials preserved with hydrochloric acid Care was taken to ensure <br /> that no air bubbles were present in the VOAs after filling and capping Ground-water sample <br /> containers were labeled with the well designation, date, time, and samplers initials <br /> 3 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> Following collection, each ground water sample was immediately placed in an ice chest and cooled <br /> to 4' C Each sample was logged on a chain-of-custody form, placed in a chilled container and <br />' transported to Alpha Analytical Laboratories Inc (AAL) in Ukiah, California, a California DTSC <br /> certified laboratory, for analysis of TPH-g, BTE&X, and halogenated volatile organic compounds <br /> (HVOCs) in accordance with EPA methods 5030 and 602, and 601, respectively The laboratory <br /> report and chains-of-custody are presented in Appendix B <br />' 3 4 PURGED WATER SAMPLE COLLECTION <br /> Twenty-rune drums of purged water are presently stored at the site The purged water has <br /> accumulated from quarterly samphng at the site On 24 July 1995, samples were collected from each <br /> drum on-site using PVC bailers and transported to AAL for analysis The 29 samples were <br /> composited at the laboratory into three samples for analysis Each composite sample was analyzed <br /> for TPH-g, BTE&X and HVOCs <br />' 4.0. FINDINGS <br />' 4 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> The relative elevation of ground water in each well was calculated by subtracting the ground water <br />' depth from the surveyed relative casing elevation (Table 1) The ground water elevation rose <br /> approximately 5 79 feet in MW-2, 5 85 feet in MW-3, and 6 10 feet in MW-4 between January and <br /> April Conversely, ground water elevation dropped approximately 103 feet in MW-2, 0 89 feet in <br /> MW-3, and 0 99 feet in MW-4 between April and July 1995 <br /> In April 1995, ground water gradient at the site was calculated to be 0 003 ft/ft (approximately 16 <br /> feet per mile) directed N 40° E In July 1995, the gradient was calculated to be 0 0015 ft/ft <br />