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CONSTITUENT Concentration DMP MONITORING WELL <br /> Limit AMW-2 AMW-6 AMW-7 AMW-12 AMW-13 AMW-14 <br /> MONITORING PARAMETERS i m <br /> Barium 0.2466 0.34 0.25 <br /> Bicarbonate 508.6 520 <br /> Chromium,Hexavalent 0.005299 0.0054 0.0054 <br /> OLATILE ORGANIC COMPOUNDS <br /> 1,1-Dichloroethene 0.5 0.51 <br /> is-1,2-Dichloroethene 0.5 1.5 <br /> Dichlorodifluoromethane 0.5 1.7 1.0 <br /> etrachloroethene 0.5 25 18 <br /> richloroethene 0.5 7.1 1.3 <br /> NOTES: (B)-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. For inorganic constituents, only bicarbonate <br /> in the sample from well A-13 and barium in the sample from well A-14 exhibited <br /> increasing trends that also exceeded a CL,though neither concentration represents a <br /> significant increase above the CL. For organic constituents, only cis-1,2-DCE in the <br /> sample from well A-13 exhibited an increasing trend,which also exceeded its CL. Since <br /> cis-1,2-DCE is a daughter product of TCE,the increasing cis-1,2-DCE trend observed in <br /> samples from well AMW-13 suggests that natural degradation by reductive <br /> dechlorination is occurring in the vicinity of this well. <br /> Well Number Increasing Trends Decreasing Trends <br /> AMW-2 Nitrate-N None Apparent <br /> AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N Arsenic <br /> AMW-7 Bicarbonate,Chloride,Nitrate-N, None Apparent <br /> Specific Conductance, Sulfate,TDS <br /> AMW-12 Bicarbonate Calcium,Chloride,Magnesium,Strontium <br /> AMW-13 Bicarbonate,cis-1,2-DCE Nitrate-N <br /> AMW-14 Barium,Calcium,Magnesium, Specific Conductance,TDS,DCDFM, <br /> Potassium, Sodium, Strontium TCE <br /> 3.1.5 Corrective Action Program <br /> Field and laboratory results for CAP wells for the first quarter 2008 monitoring period are <br /> summarized in Table 3-2. Data were graphed on time-series concentration plots by Herst <br /> & Associates from data collected through the first quarter 2008, and are presented in <br /> Appendix D. As shown in Table 3-2, nine VOCs were detected in CAP wells during the <br /> current monitoring period(although ethanol is a suspected field/laboratory contaminant). <br /> DA2007 0W\FA_IQ08.doc <br /> 10 Geologic Associates <br />