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3.ANNUAL REPORT FOR 2014 ' <br /> As shown in Figure 3 of this report and Figure 3 in Appendix F, groundwater flow patterns <br /> were consistent for the March 5, 2014,and September 10,2014, data. These groundwater <br /> flow patterns are also consistent with flow patterns from historical monitoring events before <br /> and after the active remediation systems (GWETS and SVETS) were shut down in February ' <br /> 2004 for the 3-year bioremediation pilot study. Groundwater flow is described in Section 2. <br /> 3.1.2 NAPH ' <br /> NAPH was not detected in any of the groundwater monitoring wells in 2014. NAPH has not <br /> been detected at the site since 2002. <br /> 3.1.3 BTEX and TPH ' <br /> BTEX and TPH constituents were not detected in the shallow downgradient wells (M-8, <br /> N-19, and N-20) during the first and second semiannual sampling events in 2014,which is ' <br /> consistent with the historical monitoring results. Well M-8 was able to be sampled only <br /> during the first semiannual monitoring event due to insufficient water for sampling during <br /> the second semiannual monitoring event. BTEX and TPH constituents also were not <br /> detected in the deeper well (N-24) during the first and second semiannual events in 2014. <br /> BTEX and TPH constituents were not detected in well N-18 as they had been detected in the ' <br /> past several years at low concentrations. The previous anomalous detections occurred from <br /> 2010 through 2013,which is consistent with the construction and use of farm buildings in <br /> the immediate vicinity of this well. A shallow seep was observed near N-18 during this ' <br /> time,which could have been from the building septic system. <br /> BTEX and TPH constituents continue to be detected in the remaining monitoring wells, <br /> which are located in the former release area (wells N-7 and N-15),on the plume fringe <br /> (wells 0-1,N-8,and N-16),and in the former extraction wells (RW-1 and N-17). As shown in <br /> the time-series concentration charts in Appendix D,since the start of the bioremediation <br /> pilot test, the long-term BTEX and TPH concentration trends have continued to decrease <br /> significantly for the wells with lower concentrations located on the plume fringe (wells 0-1, <br /> M-10, and N-8) and for the wells with higher concentrations located in the former release ' <br /> (source) area (wells N-7 and N-15). <br /> All these wells historically had NAPH,which is no longer detectable. The long-term <br /> concentrations for former extraction well RW-1 have exhibited a decreasing trend since <br /> monitoring for this well began in 2005. The decreases in wells M-10 and 0-1 have occurred <br /> to such an extent that well 0-1 is almost no longer in the hydrocarbon plume and well M-10 <br /> is now outside the plume. ' <br /> Before the start of the bioremediation pilot test,no long-term BTEX and TPH concentration <br /> trends for extraction well N-17 and nearby monitoring well N-16 were apparent. This ' <br /> potentially was due to extraction at well N-17 pulling hydrocarbons downgradient from the <br /> areas of higher contamination near the source area, which sustained the hydrocarbon <br /> concentrations. Since the start of the bioremediation pilot test in February 2004, the <br /> concentrations in wells N-16 and N-17 have shown similar behaviors, described in the <br /> following paragraph. <br /> Overall, the concentrations of BTEX and TPH constituents began to increase after extraction <br /> stopped from well N-17 in February 2004. This likely occurred because clean, downgradient <br /> 3.2 ES101214202053SCO <br />