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Well Increasing Trends Decreasing Trends Number AMW-2 Bicarbonate,Nitrate, Specific Conductance, None Apparent TDS AMW-6 Barium,Bicarbonate,Chloride,Magnesium, None Apparent Nitrate, Specific Conductance, Strontium, TDS AMW-7 Bicarbonate,Calcium,Chloride, Magnesium, Hexavalent Chromium, Potassium, Nitrate, Specific Conductance, Sulfate,TDS Strontium AMW-12 None Apparent Calcium,Chloride AMW-13 Bicarbonate,Sulfate Chloride,Nitrate,TCE AMW-14 Barium,Calcium,Chloride,Hexavalent PCE Chromium,Magnesium,Nitrate, Potassium, Sodium,Strontium,Sulfate Notes: TDS—Total Dissolved Solids PCE—Tetrachloroethene TCE—Trichloroethene With the exception of the barium concentration measured in well AMW-14, no constituent that exhibited a statistically significant increasing trend during the fourth quarter 2012 monitoring event also exceeded their concentration limit. It should be noted, however, that the barium concentration measured in the sample collected from well AMW-14 (0.280 mg/L) is within the historical range of values observed at this well. No increasing trends were noted for VOC constituents in the DMP wells. However, decreasing trends were noted for one VOC in wells AMW-13 and AMW-14. Corrective Action Program Field and laboratory results for CAP wells for the fourth quarter 2012 monitoring period are summarized in Table 3-2. As shown in Table 3-2, a total of 16 different VOCs were detected in CAP wells during the current monitoring period. Well AMW-1 had the greatest number of VOCs (15) with seven 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. For constituents whose historical data consists primarily of non-detects(carbonate alkalinity, oil and grease, volatile petroleum hydrocarbons, and VOCs), trend evaluations were performed on data from the earliest detection through the present. 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 the data. Trend analyses, performed by Herst& Associates, are presented in Appendix D and are summarized on the following table. 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. C:\2012-0025\FA4Q12.d" Geo-Logic Associates