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For the DMP wells at the Austin Unit, CLs are used for the water quality protection <br /> standards(WQPS). The CLs shown in Table 3-1 were calculated by Herst&Associates <br /> using Sanitas®, a state-approved statistical software program. Based on a comparison of <br /> the data obtained during the second quarter 2007 monitoring period,the following <br /> analytes were found to exceed a CL. The results of the statistical analyses performed by <br /> Herst&Associates are presented in Appendix D. <br /> CONSTITUENT Concentration DMP MONITORING WELL <br /> Limit AMW-28AMW-6 I AMW-7 I AMW-12 I AMW-13 IAMW-14 <br /> MONITORING PARAMETERS( ) <br /> Barium 1 02462 1 1 1 1 1 0.25 <br /> Chromium,Hexavalent 1 0.005059 1 1 1 0.0051 <br /> VOLATILE ORGANIC COMPOUNDS <br /> [Dichlorodifluoromedme 0.5 0.66 <br /> etrachloroethene 0.5 2.0 1 9.6 <br /> richloroethene 0.5 1.1 <br /> NOTES: (s)-Background Well. <br /> DMP-Trend Analyses <br /> In order to evaluate changes in water quality in DMP wells at the Austin Unit,historical <br /> trends in groundwater were evaluated beginning in 1994 when the groundwater treatment <br /> facility began operation. The observed groundwater quality constituent trends were <br /> evaluated using Sen's Slope trend analyses to determine if significant increasing or <br /> decreasing trends were evident in the data. Trend analyses,performed by Herst& <br /> Associates, are presented in Appendix D and summarized below. Wells and analytes not <br /> discussed below either do not show significant trends(rising or falling)or have too few <br /> data points to establish meaningful trends. As shown in the following table,no <br /> increasing trends were noted for VOC constituents, and none of the constituents that <br /> exhibited an increasing trend exceeded a CL. In addition,decreasing trends were noted <br /> for PCE and TCE in well AMW-14. <br /> Well Number Increasing Trends Decreasing Trends <br /> AMW-2 Nitrate-N,Specific Conductance Arsenic <br /> AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N Sulfate <br /> AMW-7 Bicarbonate,Chloride,Nitrate-N, None Apparent <br /> Specific Conductance,TDS <br /> AMW-12 Bicarbonate Calcium,Chloride,Magnesium,Strontium <br /> AMW-13 Bicarbonate Nitrate-N,Potassium <br /> AMW-14 Calcium,Magnesium,Potassium, Chloride,Specific Conductance,TDS, <br /> Sodium,Strontium PCE,TCE <br /> 3.1.5 Corrective Action Program <br /> Field and laboratory results for CAP wells for the second quarter 2007 monitoring period <br /> are summarized in Table 3-2. Data were graphed on time-series concentration plots by <br /> Herst&Associates from data collected through the second quarter 2007, and are <br /> presented in Appendix D. As shown in Table 3-2, excluding a suspected laboratory <br /> contaminant, 13 VOCs were measured in CAP wells during the current monitoring period <br /> D:X2007_0043\ForwardAustin_sp07.doe <br /> 10 <br /> Geologic Associates <br />