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calculated using Sanitas®, a state-approved statistical software program. Details
<br /> regarding the concentration limit calculations are discussed in Appendix D. Based on a
<br /> comparison of the data obtained during the second quarter 2013 monitoring period,
<br /> inorganic CLs were exceeded for barium in the samples collected from wells AMW-13
<br /> and AMW-14; for chloride in wells AMW-12 and AMW-14; and for hexavalent
<br /> chromium in wells AMW-6 and AMW-7. For any inorganic monitoring parameter that
<br /> exceeded a CL, Mann-Kendall/ Sen's Slope trend analyses was performed to determine
<br /> if statistically significant increasing temporal trends were evident in the data. Trend
<br /> analyses indicate statistically significant increasing temporal trends for barium
<br /> concentrations in well AMW-14 and for chloride concentrations measured in wells
<br /> AMW-l2 and AMW-14. Trend analyses calculations are presented in Appendix D.
<br /> Corrective Action Program
<br /> Field and laboratory results for CAP wells for the second quarter 2013 monitoring period
<br /> are summarized in Table 3-2. As shown in Table 3-2, 15 VOCs were detected in CAP
<br /> wells during the current monitoring period. Well AMW-1 had the greatest number of
<br /> VOCs with seven 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,pH,Sodium, Sulfate, 1,2-DCB, 1,2-DCP
<br /> Chlorobenzene,cis-1,2-DCE
<br /> AMW-3 - -
<br /> AMW-4 pH Potassium,TDS,PCE
<br /> AMW-5R - Bicarbonate
<br /> AMW-10 Sulfate Barium,Bicarbonate,Calcium,Hexavalent
<br /> Chromium,Magnesium,Nitrate,Potassium,
<br /> Sodium,Strontium,TDS,PCE,TCE
<br /> AMW-11 pH Hexavalent Chromium,Magnesium,Nitrate,
<br /> Potassium,TDS
<br /> AMW-18 - -
<br /> AMW-19 Barium Hexavalent Chromium,Nitrate,Sulfate
<br /> AMW-19BR Barium,Calcium,pH Hexavalent Chromium,Nitrate, Sulfate,cis-1,2-
<br /> DCE
<br /> Notes: 1,1-DCA—1,1-Dichloethane 1,2-DCB—1,2-Dichlorobenzene cis-1,2-DCE—cis-1,2-Dichloroethene
<br /> 1,2-DCP—1,2-Dichloropropane PCE—Tetrachloroethene TCE—Trichloroethene
<br /> TDS—Total Dissolved Solids
<br /> C:\2013-0021\FA_2Q13.doc 10 Geo-Logic Associates
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