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facility began operation. The observed groundwater quality constituent trends were evaluated using Sen's Slope trend analyses to determine if significant increasing or decreasing trends were evident in the data. Trend analyses, performed by Herst & Associates, are presented in Appendix D and summarized below. Wells and analytes not discussed below either do not show significant trends (rising or falling) or have too few data points to establish meaningful trends. As shown in the following table, with the exception of cis-1,2-DCE, no increasing trends were noted for VOC constituents, and none of the constituents that exhibited an increasing trend exceeded a CL. Since cis-1,2- DCE is"a daughter product of TCE, the increasing cis-1,2-DCE trend observed in samples from well AMW-13 indicates that natural degradation by reductive dechlorination is occurring in the vicinity of this well. Well Number Increasing Trends Decreasing Trends AMW-2 Nitrate-N,Specific Conductance Arsenic AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N Arsenic AMW-7 Bicarbonate,Chloride,Nitrate-N, None Apparent Specific Conductance,Sulfate,TDS AMW-12 Bicarbonate Calcium,Chloride,Magnesium,Strontium AMW-13 Bicarbonate,cis-1,2-DCE Nitrate-N AMW-14 Barium,Calcium,Magnesium, j::Specific Conductance,TDS,TCE Potassium, Sodium,Strontium 3.1.5 Corrective Action Program Field and laboratory results for CAP wells for the fourth quarter 2007 monitoring period are summarized in Table 3-2. Data were graphed on time-series concentration plots by Herst& Associates from data collected through the fourth quarter 2007, and are presented in Appendix D. As shown in Table 3-2, excluding suspected laboratory contaminants, 13 VOCs were detected in CAP wells during the current monitoring period. The greatest number of VOCs, including nine measured above the PQL, were detected in the sample from well AMW-1. 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 Sen's Slope trend analyses to determine if significant increasing or decreasing trends were evident in the data. Trend analyses,performed by Herst & Associates, are presented in Appendix D and are summarized below. Wells and analytes not discussed below either do not show significant trends (rising or falling) or have too few data points to establish meaningful trends. As shown in the following table, significant increasing trends were calculated for one or more VOC constituents in CAP wells AMW-1, AMW-10, and AMW-19, while decreasing trends were calculated for one or more VOC constituents in CAP wells AMW-10 and AMW-11. D:12007_0043\Fonra rd Austin_4Q07.d oc 11 GeoLogic Associates