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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-2 AMW-6 AMW-7 AMW-13 AMW-14 <br /> MONITORING PARAMETERS(mg/1) <br /> Barium 1 0.2284 0.256 0.244 <br /> Chloride 1 77.69 82.2 <br /> Chromium(hexavalent) 1 0.004872 .0063j <br /> OLATILE ORGANIC COMPOUNDS ) <br /> etrachloroethene 1.0 8.2 2.0 <br /> richloroethene 1.0 2.2 <br /> NOTES: (B)-Background Well. <br /> j -Trace Value <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 Mann-Kendall / Sen's Slope trend analyses to determine if significant <br /> increasing or decreasing trends were evident in the data. Trend analyses,performed by <br /> Herst&Associates, are presented in Appendix D and summarized below. Wells and <br /> analytes not discussed below either do not show significant trends (rising or falling) or <br /> have too few data points to establish meaningful trends. <br /> Well Number Increasing Trends Decreasing Trends <br /> AMW-2 Bicarbonate,Nitrate-N,Specific pH <br /> Conductance <br /> AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N, None Apparent <br /> Strontium,TDS <br /> AMW-7 Bicarbonate, Calcium,Chloride, Potassium <br /> Magnesium,Nitrate-N, Specific <br /> Conductance, Sulfate,TDS <br /> AMW-12 None Apparent Barium,Calcium,Chloride,Magnesium, <br /> Potassium,Strontium <br /> AMW-13 Bicarbonate Nitrate-N <br /> AMW-14 Barium,Calcium,Hexavalent Chromium, PCE,TCE <br /> Magnesium,Nitrate-N,Potassium, <br /> Sodium,Strontium <br /> With the exception of barium concentrations measured in well AMW-14, no constituents <br /> that exhibited a statistically significant increasing trend during the fourth quarter 2010 <br /> monitoring event and also exceeded their concentration limits. It should be noted, <br /> however, that the barium concentration measured in the sample collected from well <br /> AMW-14(0.244 mg/L) during the current monitoring period is within the historical <br /> range of values observed at this well, and is well below the state primary drinking water <br /> standard(1 mg/L). <br /> D:\2010_0013\FA_4Q10.doc <br /> 11 Geologic Associates <br />