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measured in wells AMW-12 and AMW-14. Trend analyses calculations are presented in
<br /> 0 Appendix D.
<br /> Corrective Action Program
<br /> Field and laboratory results for CAP wells for the first quarter 2013 monitoring period are
<br /> summarized in Table 3-2. As shown in Table 3-2, 15 VOCs were detected in CAP wells
<br /> during the current monitoring period. Well AMW-1 had the greatest number of VOCs
<br /> with six measured above their PQLs.
<br /> Trend Analyses
<br /> In order to evaluate the effectiveness of corrective action measures, particularly with the
<br /> groundwater treatment facility (GTF),trend analyses were performed for CAP wells at
<br /> the Austin Unit, beginning in 1994 when the GTF began operation. The observed
<br /> groundwater quality constituent trends were evaluated using Mann-Kendall / Sen's Slope
<br /> trend analyses to determine if significant increasing or decreasing trends were evident in
<br /> the data. Trend analyses, are presented in Appendix D and are summarized below. Wells
<br /> and analytes not discussed below either do not show significant trends (rising or falling)
<br /> or have too few data points to establish meaningful trends.
<br /> Well Increasing Trends Decreasing Trends
<br /> Number
<br /> AMW-1 Arsenic,Barium, 1,1-DCA, Nitrate-N,pH, Sulfate,DCDFM, Chloroethane
<br /> Chlorobenzene,cis-1,2-DCE
<br /> AMW-3 Chloride,Nitrate-N Arsenic,Barium,pH
<br /> AMW-4 pH Chloride,Potassium,TDS, 1,1-DCA, 1,2-DCP,
<br /> 1,4-DCB,Benzene,cis-1,2-DCE,DCDFM,PCE,
<br /> TCE,trans-1,2-DCE,Vinyl Chloride
<br /> AMW-5R None Calculated Bicarbonate,Chloride
<br /> AMW-10 Sulfate Barium,Bicarbonate,Calcium,Chloride,
<br /> Hexavalent Chromium,Magnesium,Nitrate-N,
<br /> Potassium, Sodium, Strontium,TDS, 1,1-DCA,
<br /> DCDFM,PCE,TCE
<br /> AMW-11 pH Chloride,Hexavalent Chromium,Magnesium,
<br /> Potassium,TDS, 1,1-DCA, 1,2-DCP,cis-1,2-DCE,
<br /> DCDFM,PCE,TCE,trans-1,2-DCE
<br /> AMW-18 Bicarbonate Chloride,Hexavalent Chromium,Potassium,
<br /> Sodium,Sulfate,TDS
<br /> AMW-19 Barium Hexavalent Chromium,Nitrate-N, Sulfate
<br /> AMW-19BR Chloride,pH Hexavalent Chromium,Nitrate-N, Sulfate
<br /> Notes: 1,4-DCB—1,4-dichlobenzene 1,2-DCP—1,2-dichloropropane trans-1,2-DCE—trans-1,2-Dichloroethene
<br /> As shown in the table above, significant increasing trends were calculated for three VOC
<br /> constituents in CAP well AMWA, while decreasing VOC trends were noted for several
<br /> VOCs in CAP wells AMW-1, AMW-4, AMW-10, and AMW-11. The increasing trend
<br /> exhibited for cis-1,2-DCE at well AMW-1 and generally decreasing (organic and
<br /> inorganic)trends noted in all of the CAP wells, suggests that corrective action measures
<br /> have been successful in reducing facility related groundwater impacts downgradient of
<br /> the Austin Unit.
<br /> CA2013-0021\FA_1Q13.doc 11 Geo-Logic Associates
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