ARCHIVED REPORTS - OZONE PILOT TEST & SEMI-ANNUAL GROUNDWATER MONITORING REPORT - THIRD QUARTER 2014

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' 20 March 2015 AGE Project No. 00-0769 ' Page 17 of 19 ' compared to previous sampling events. Trend graphs illustrating dissolved TPH-g, benzene, and 1,2-DCA concentrations versus time in well MW-1 are presented in Appendix F; the ozone pilot test operational period is depicted in the ' graph. • A moderate to significant reduction in dissolved concentrations of TPH-g, BTEX, TAME, and 1,2-DCA was observed at well MW-3B (screened 20-40 feet bsg) in ' August 2014 compared to baseline concentrations; samples were not collected from well MW-3B in October 2014. Well MW-3B is located approximately 12 feet ' from the closest ozone injection well (OZ-2: screened 66-70 feet bsg). TPH-g concentrations decreased from 8,000 pg/I in June 2013 to 2,400 pg/I in August 2014 (70% reduction); BTEX concentrations decreased from 110 pg/I, 14 pg/l, 61 pg/I, and 149.4 pg/I, respectively in June 2013 to concentrations of 40 pg/I, 4.2 pg/l, 2.7 pg/l, and 16.8 pg/l, respectively in August 2014 (63% to 95% reduction); TAME concentrations decreased from 1.3 pg/I in June 2013 to non- detect (<1.0) in August 2014; and 1,2-DCA concentrations decreased from 3.1 pg/I in June 2013 to non-detect (<0.5) in August 2014. Trend graphs illustrating dissolved TPH-g, benzene, and 1,2-DCA concentrations versus time t in MW-3B are presented in Appendix F; the ozone pilot test operational period is depicted in the graph. • A significant reduction in dissolved TPH-g concentrations was observed at well ' MW-3A (screened 100-105 feet bsg) at the conclusion of the pilot test compared to the baseline concentration. MW-3A is located approximately 12 feet from the closest ozone injection well (OZ-2: screened 66-70 feet bsg). TPH-g ' concentrations decreased from 14,000 pg/I in June 2013 to 3,100 pg/I in October 2014 (77% reduction). BTEX, TAME, and 1,2-DCA concentrations remained generally stable or increased and decreased slightly in October 2014 compared to baseline concentrations detected in June 2013 Trend graphs illustrating dissolved TPH-g, benzene, and 1,2-DCA concentrations versus time in MW-3A are presented in Appendix F; the ozone pilot test operational period is depicted in ' the graph. • A moderate reduction in dissolved concentrations of TPH-g, TEX, TAME, and ' 1,2-DCA was observed at well MW-2B (screened 20-40 feet bsg) in August 2014 compared to baseline concentrations; samples were not collected from well MW-2B in October 2014. Well MW-2B is located approximately 40 feet from the ' closest ozone injection well (OZ-4). TPH-g concentrations decreased from 7,300 pg/I in June 2013 to 2,500 pg/I in August 2014 (65% reduction); TEX concentrations decreased from 55 pg/I, 90 pg/I, and 350 pg/I, respectively in ' June 2013 to concentrations of 27 pg/I, 29 pg/l, and 78 pg/l, respectively in August 2014 (50% to 78% reduction); TAME concentrations decreased from 3.7 pg/I in June 2013 to non-detect in August 2014; and 1,2-DCA concentrations ' decreased from 19 pg/I in June 2013 to 11 pg/I in August 2014 (42% reduction). Benzene concentrations increased from 34 pg/I in June 2013 to 74 pg/I in August 2014. However, concentrations of benzene in MW-2B prior to June 2013 had Advanced GeoEnvironmental Inc.