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number of VOCs(two)measured above the PQL in well -14. For the DMP wells at the Austin Unit, CLs are used for the water quality protection standards (WQPS). The CLs shown in Table 3-1 were calculated by Herst&Associates using Sanitae, a state- approved statistical software program are presented in Appendix D. Based on a comparison of the data obtained during the third quarter 2006 monitoring period, the following analytes were found to exceed a CL. CONSTITUENT Concentration DMP MONrrORING WELL Limit AMW-2* AMW-6 AMW-7 AMW-12 AMW-13 AMW-14 ONITORING PARAMETERS m arium 0.2441 1 0.250 :arbonate 10 17 hromium(hexavalent) 0.004951 0.0060 VOLATILE ORGANIC COMPOUNDS romofonn 0.33 1.9** 1.6** 1.8** bromochlommethane 0.14 0.73** 0.68** ehachlomethene 0.15 1.6 7.6 richloroethene 0.18 1.0 NOTES: (*)-Background Well. (j)-Trace Value(between MDL and PQL). (**)-Confirmed Laboratory Contaminant. DMP-Trend Analyses In order to evaluate changes in water quality in DMP wells at the Austin Unit,historical trends in groundwater were evaluated beginning in 1994 when the groundwater treatment facility(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 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, increasing trends were noted for two VOCs in DMP well AMW-13,while decreasing VOC trends were noted in well -14. Of the increasing constituent trends identified during the third quarter 2006 monitoring period, only the PCE concentration in well AMW-13 exceeded a concentrations limit. Well Number Increasing Trends Decreasing Trends AMW-2 Nitrate-N,Specific Conductance Arsenic AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N Arsenic,Sulfate AMW-7 Barium,Chloride,Nitrate-N,Specific Arsenic Conductance,TDS AMW-12 Bicarbonate Arsenic,Chloride AMW-13 Bicarbonate,PCE,TCE Potassium,Nitrate-N AMW-14 Calcium,Magnesium,Potassium,Sodium, Chloride,Specific Conductance, Strontium Sulfate,TDS,PCE,TCE 3.1.5 Corrective Action Program Field and laboratory results for CAP wells for the third quarter 2006 are summarized in Table 3-2. Data were graphed on time-series concentration plots by Herst &Associates from data collected through the third quarter 2006, and are presented in Appendix D. D:%2003 02IWorwa _ 11 Geologic Associates