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with the greatest number of VOCs,including six measured above the PQL,measured in
<br /> the sample from well AMW-1.
<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 Sen's Slope trend analyses
<br /> to determine if significant increasing or decreasing trends were evident in the data. Trend
<br /> analyses,performed by Herst&Associates, are presented in Appendix D and are
<br /> summarized below. Wells and analytes not discussed below either do not show
<br /> significant trends(rising or falling)or have too few data points to establish meaningful
<br /> trends. As shown in the following table, significant increasing trends were calculated for
<br /> one or more VOC constituents in CAP wells AMW-1,AMW-10, and AMW-19, while
<br /> decreasing trends were calculated for one or more VOC constituents in CAP wells
<br /> AMW-1,AMW-11,and AMW-18.
<br /> Well Increasing Trends Decreasing Trends
<br /> Number
<br /> AMW-1 Barium,Bicarbonate,Specific Chloride,Nitrate-N,pH,Sulfate,
<br /> Conductance,cis-1,2-DCE,Vinyl Chloride DCDFM
<br /> AMW-3 None Apparent None Apparent
<br /> AMW4 None Apparent Chloride,Barium,Bicarbonate,
<br /> Calcium,Magnesium,Potassium,
<br /> Strontium,TDS
<br /> AMW-5 None Apparent None Apparent
<br /> AMW-10 Sulfate,cis-1,2-DCE None Apparent
<br /> AMW-11 pH Calcium,Chloride,Magnesium,
<br /> Strontium,Specific Conductance
<br /> TDS,cis-1,2-DCE,DCDFM,PCE,
<br /> TCE
<br /> AMW-18 Barium,Bicarbonate Arsenic,Sulfate,Sodium,
<br /> 1,2-Dichloro ro ane
<br /> AMW-19 PCE Arsenic,Sodium,Sulfate
<br /> The presence of cis-1,2-DCE suggests reductive dechlorination is occurring in the
<br /> vicinity of wells AMW-1,AMW-4,AMW-10, and AMW-19A and in particular in the
<br /> vicinity of wells AMW-1 and AMW-10 where an increasing trend was calculated. As
<br /> summarized in the Annual Corrective Action Evaluation prepared by Herst&Associates
<br /> (2006),the overall groundwater quality at the site is generally improving.
<br /> 3.1.6 Domestic Well Monitoring
<br /> Two domestic wells (7898-A and 8106-A)were sampled on May 7,2007. Table 3-3
<br /> summarizes the current analytical results for the domestic well samples collected. As
<br /> shown on Table 3-3, four VOCs were measured in the sample from domestic well
<br /> 7898-A with three VOCs measured above the PQL,while seven VOCs were measured in
<br /> the sample from domestic well 8106-A with six VOCs measured above the PQL.
<br /> D:\2007_0043\Fwv2rdAus[in_VO7.d" "-
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<br /> Geologic Associates
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