|
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.
<br /> Well Number Increasing Trends Decreasing Trends
<br /> AMW-2 Nitrate-N, Specific Conductance Arsenic
<br /> AMW-6 Barium,Bicarbonate,Chloride,Nitrate-N, None Apparent
<br /> Strontium
<br /> AMW-7 Bicarbonate,Calcium,Chloride, None Apparent
<br /> Magnesium,Nitrate-N, Specific
<br /> Conductance,Sulfate,TDS
<br /> AMW-12 None Apparent Calcium,Chloride,Magnesium,
<br /> Potassium,Strontium
<br /> AMW-13 Bicarbonate Nitrate-N
<br /> AMW-14 Barium,Calcium,Magnesium, None Apparent
<br /> Potassium, Sodium,Strontium
<br /> With the exception of barium concentrations measured in well AMW-14,no constituents
<br /> that exhibited a statistically significant increasing trend during the first quarter 2009
<br /> monitoring event and also exceeded their concentration limits.
<br /> 3.1.5 Corrective Action Program
<br /> Field and laboratory results for CAP wells for the first quarter 2009 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 2009, and are presented in
<br /> Appendix D. As shown in Table 3-2, 13 VOCs were detected in CAP wells during the
<br /> current monitoring period. Well AMW-1 had the greatest number of VOCs (12),
<br /> including five 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 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 A -1,AMW-10, and AMW-19, while
<br /> decreasing VOC trends were noted in CAP wells AMW-4, AMW-5/5R,AMW-10, and
<br /> AMW-11.
<br /> Well Increasing Trends Decreasing Trends
<br /> Number
<br /> AMW-1 Barium,Bicarbonate,Specific Nitrate-N,pH,Sulfate,DCDFM
<br /> Conductance, 1,1-DCA,cis-1,2-DCE,
<br /> Vinyl Chloride
<br /> AMW-3 None Apparent None Apparent
<br /> D:X2009_001 TFA_1 Q09.d oc
<br /> 11 Geologic Associates
<br />
|