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Non-Statistical Data Analysis The non-statistical V OC water analyses performed on the DMP well data indicates that there were three non-statistical exceedances for VOCs. The non-statistical exceedances were identified at well AMW-6 as a result of the detection of tetrachloroethene (PCE) and dichlorodifluoromethane (DCDFM) above the PQL and trichloroethene (TCE) at estimated trace concentrations; at well AMW-13 as a result of the detection of PCE,and TCE at concentrations above the PQL and 1,1-dichloroethane (1,1-DCA), cis-1,2- dichloroethene (cis-1,2-DCE), DCDFM, and trichlorofluoromethane (TCFM)at estimated trace concentrations. Trend analyses indicate that statistically significant increasing temporal trends were calculated for PCE and TCE in well AMW-13. Trend analyses are included in Appendix D. These results are similar to previous results and it is recommended that wells AMW-6, AMW-13, and AMW-14 be re-designated as CAP wells since they have historically contained VOCs. Concentration Limit Thresholds As specified in RWQCB Order No. R5-2003-0049 the routine monitoring parameters obtained during the third quarter 2013 monitoring period were compared to interwell CLs established for the Austin Unit DMP wells. The CLs shown in Table 3-1 were calculated using Sanitas®, a state-approved statistical software program. Details regarding the concentration limit calculations are discussed in Appendix D. Based on a comparison of the data obtained during the third quarter 2013 monitoring period, inorganic CLs were exceeded for barium in the samples collected from wells AMW-12 and AMW-13; for chloride in well AMW-12; and for hexavalent chromium in well AMW-7. For any inorganic monitoring parameter that exceeded a CL, Mann-Kendall/Sen's Slope trend analyses was performed to determine if statistically significant increasing temporal trends were evident in the data. Trend analyses indicate statistically significant increasing temporal trends for barium and chloride concentrations in well AMW-12. Trend analyses calculations are presented in Appendix D. Corrective Action Program Field and laboratory results for CAP wells for the third quarter 2013 monitoring period are summarized in Table 3-2. As shown in Table 3-2, 13 VOCs were detected in CAP wells during the current monitoring period. Well AMW-1 had the greatest number of VOCs with eight measured above their PQLs. Trend Analyses In order to evaluate the effectiveness of corrective action measures,particularly with the groundwater treatment facility (GTF),trend analyses were performed for CAP wells at the Austin Unit, beginning in 1994 when the GTF began operation. The observed groundwater quality constituent trends were evaluated using Mann-Kendall/ Sen's Slope trend analyses to determine if significant increasing or decreasing trends were evident in C:\2013-0021\FA_3Q13.doc 10 Geo-Logic Associates