SITE INFORMATION AND CORRESPONDENCE FILE 2

Home Browse Search

07 November 2011 AGE-NC Project No. 00-0769 Page 5 of 7 • TPH-g were detected in ground water samples collected from wells MW-4E and MW-5E at concentrations of 3,600 pg/I. BTEX compounds were detected in the same samples at maximum concentrations of 250 pg/I benzene (MW-4E), 140 pg/I toluene (MW-4E & MW-5E), 60 pg/I ethylbenzene, and 256 pg/I xylenes (MW-4E). • 1,2-DCA and TAME were detected in ground water samples collected from wells MW-4E and MW-5E at maximum concentrations of 5.9 pg/I (MW-4E) and 2.6 pg/I (MW-5E), respectively. • No additional analytes were detected above laboratory detection limits in the ground water samples analyzed. The estimated extent of dissolved TPH-g, benzene, and 1,2-DCA for HU-1 through HU-5 are illustrated in Figures 7 through 11, respectively. Analytical results of ground water samples collected in October 2011 are summarized in Table 2. The laboratory report (CTEL Lab Project. No. CT214-1110128), quality assurance/quality control report, and chain-of-custody form are included in Appendix D. Electronic deliverable format(EDF)files and depth to water data will be uploaded to the State GeoTracker database system. Graphs illustrating depth to ground water, ground water elevation and TPH-g concentrations versus time (trend graphs) for each hydrogeologic unit are presented in Appendix E. 4.0. CONCLUSIONS Based upon the results of ground water monitoring, AGE presents the following conclusions: • On 14 October 2011, depth to ground water at the site ranged from 16.24 feet btoc (MW-7A)to 23.12 feet btoc(MW-5E)and ground water elevations ranged from 6.22 feet (MW-7A) below NAVD88 to 12.32 feet (MW-7D) below NAVD88. • On 14 October 2011, ground water on-site was generally inferred to be flowing towards the northeast and southeast in HU-1 and HU-2, respectively, toward the southeast in HU-3, and toward the northwest in HU-4. • TPH-g, BTEX, 1,2 DCA, and TAME were reported in every hydrogeologic unit. • During the fourth quarter 2011, TPH-g and BTEX concentrations generally increased slightly to moderately in samples collected from wells MW-3B and MW-6B and decreased slightly to moderately in samples collected from wells MW-2B, MW-3A, MW-4 (B,D&E), and MW-5 (A-E) compared to the previous sampling event. TPH-g and BTEX concentrations remained generally stable in all Advanced GeoEnvironmental,Inc.