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flow rate of 240,953 gallons per day. During the monitoring period, it is calculated that the GTF removed approximately 1.12 pounds of VOCs. 3.2 CONSTITUENTS OF CONCERN During the first quarter 2013 monitoring period, groundwater, domestic well, and surface water samples from the Austin Unit were analyzed for the five-year COCs listed in RWQCB Order No. R5-2003-0049 and are summarized in Tables 3-1, 3-2, 3-3, and 3-5. As shown in Tables 3-1, 3-2, 3-3, and 3-5, with the exception of one semi-volatile organic compound (SVOC)that was measured at a trace concentration(di-n-butyl phthalate) in the sample from well AMW-4, no organic COCs were detected in the groundwater and surface water samples. It should be noted that phthalates are used as plasticizers in polyvinyl chloride (PVC), which is a common monitoring well material. Therefore, the presence of di-n-butyl phthalate in well AMW-4 is believed to be a field contaminant. Several inorganic COCs were detected in both up-gradient and down-gradient wells and surface water stations. The similarity in the concentrations in both up-gradient and down-gradient wells and surface water stations suggest that the inorganic COCs are naturally occurring. A comparison of inorganic COCl to Federal and State maximum contaminant levels (MCLs) for drinking water, indicate that the MCL for antimony (0.006 mg/L) was exceeded in all groundwater wells except AMW-4, AMW-5R, AMW-6, and AMW-10. No other inorganic MCLs were exceeded during the COC monitoring event. 3.3 SUMMARY Groundwater quality conditions beneath the Austin Unit during the first quarter 2013 monitoring period were generally similar to historical results. During the first quarter 2013 monitoring period, non-statistical exceedances for VOCs were identified at DMP wells AMW-6, AMW-13 and AMW-14. Trend analyses indicate that statistically significant increasing temporal trends were calculated for PCE and TCE in well AMW-13. These results are similar to previous results and it has been recommended that wells AMW-6, AMW-13, and AMW-14 be re-designated as CAP wells since they have historically contained VOCs. For the routine inorganic monitoring parameters, CLs were exceeded for constituent concentrations in DMP wells MW-2A, MW-13, MW-14, MW-15, and MW-23R. With the exception of nitrate-N concentrations measured in well MW-14 and sulfate concentrations measured in well MW-15,there were no statistically significant increasing trends calculated for the CL exceedances during the current monitoring period. In the CAP wells,trend analyses are performed instead of comparison to CLs. During the current monitoring period, statistically significant increasing trends were noted for three VOCs in CAP well AMW-1, while decreasing VOC trends were noted for several VOCs in CAP wells AMW-1, AMW-4, AMW-10, and AMW-11. The increasing trend exhibited for cis-1,2-DCE at well AMW-1 and generally decreasing (organic and inorganic)trends noted in all of the CAP wells, C:\2013-002I\FA_1QIIdoc 13 Geo-Logic Associates