|
3.1.5 Corrective Action Program
<br /> Field and laboratory results for CAP wells for the fourth quarter 2010 monitoring period
<br /> are summarized in Table 3-2. As shown in Table 3-2, five VOCs were detected in CAP
<br /> wells during the current monitoring period. Well AMW-I had the greatest number of
<br /> VOCs with four measured above the PQL.
<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, performed by Herst&Associates, are presented in Appendix D
<br /> and are 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.
<br /> Well Increasing Trends Decreasing Trends
<br /> Number
<br /> AMW-1 Barium,Bicarbonate, Specific Nitrate-N,pH,Sulfate,
<br /> Conductance, 1,1-DCA, Dichlorodifluoromethane(DCDFM)
<br /> cis-1,2-DCE
<br /> AMW-3 None Apparent None Apparent
<br /> AMW4 pH,Nitrate-N Barium,Bicarbonate,Calcium,Chloride,
<br /> Magnesium,Potassium, Sodium, Specific
<br /> Conductance,Strontium,TDS,cis-1,2-DCE,PCE,
<br /> TCE
<br /> AMW-5/5R Barium,Bicarbonate,Chloride, PCE
<br /> Nitrate-N,pH,Potassium,
<br /> Sodium,Specific Conductance,
<br /> Sulfate,TDS
<br /> AMW-10 Sulfate,cis-1,2-DCE Barium,Bicarbonate,Calcium,Chloride,
<br /> Magnesium,Nitrate-N,Potassium, Sodium,
<br /> Strontium,TDS, 1,1-DCA,DCDFM,PCE,TCE
<br /> AMW-I I pH Barium,Bicarbonate,Calcium,Chloride,
<br /> Magnesium,Potassium, Specific Conductance,
<br /> TDS, 1,1-DCA,cis-1,2-DCE,DCDFM,PCE,TCE
<br /> AMW-18 None Apparent Chloride,Nitrate-N,Potassium,Sodium,TDS
<br /> AMW-19 PCE,TCE Nitrate-N,Sodium, Sulfate,TDS
<br /> AMW-19BR pH,DCDFM Nitrate-N,Potassium, Sodium,Sulfate
<br /> As shown in the table above, significant increasing trends were calculated for one or
<br /> more VOC constituents in CAP wells AMW-1, AMW-10, AMW-19, and AMW-1 9BR,
<br /> while one or more decreasing VOC trends were noted in CAP wells AMW-1,AMW-4,
<br /> AMW-5/5R, AMW-10, and AMW-11. The increasing trend exhibited for cis-1,2-DCE at
<br /> wells AMW-1 and AMW-10, suggests reductive dechlorination is occurring in the
<br /> vicinity of these wells.
<br /> D:\2010_0013\FA_4Q10.doc 12 Geologic Associates
<br />
|