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Well <br />Increasing Trends <br />Decreasing Trends <br />Number <br />AMW-10 <br />Sulfate, cis-1,2-DCE <br />Calcium, Magnesium, Nitrate -N, <br />Potassium, Strontium, 1,1 -DCA <br />AMW-1l <br />Sodium <br />Calcium, Chloride, Magnesium, <br />Strontium, Specific Conductance TDS, <br />cis-1,2-DCE, PCE, TCE <br />AMW-18 <br />Bicarbonate <br />Arsenic, Carbonate, Chloride, Nitrate -N, <br />Potassium, Sulfate, Sodium <br />AMW-19 <br />PCE, TCE <br />Sodium, Sulfate <br />The increasing trend exhibited by cis-1,2-DCE suggests reductive dechlorination is <br />occurring in the vicinity of wells AMW-1 and AMW-10. As summarized in the Annual <br />Corrective Action Evaluation prepared by Herst & Associates (2007), the overall <br />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 5, 2008. Table 3-3 <br />summarizes the current analytical results for the domestic well samples collected. As <br />shown on Table 3-3, excluding suspected field/laboratory contaminants, two VOCs were <br />measured, both above the PQL, in the sample collected from domestic well 7898-A, and <br />five VOCs were detected in the sample collected from domestic well 8106-A, with three <br />VOCs measured above the PQL. <br />3.1.7 Surface Water Monitoring <br />Surface -water sampling was conducted at surface -water monitoring stations ASW -1 and <br />ASW -2 on May 6, 2008. Table 3-4 summarizes the current analytical results for surface <br />water samples collected at the Austin Unit and compares the results with the WQPS <br />(concentration limits). No CLs were exceeded at downgradient surface -water monitoring <br />station ASW -2, and no VOCs were detected at surface water monitoring stations during <br />the second quarter 2008 monitoring period. A comparison of upgradient (ASW -1) to <br />downgradient (ASW -2) surface water samples indicates generally similar concentrations. <br />3.1.8 Constituents of Concern <br />In addition to the routine quarterly monitoring parameters, samples were also analyzed <br />for the full suite of COCs stipulated in RWQCB Order No. R5-2003-0049 and performed <br />every five years. Table 2-1 summarizes the COCl included for the Austin Unit and <br />Tables 3-1 through 3-4 summarize the results. As shown in Tables 3-1 through 3-4 one <br />SVOC, bis(2-ethylhexyl)phthalate, a common field/lab contaminant was measured at <br />trace levels in the samples collected from wells AMW-6, AMW-7, AMW-5R, and <br />AMW-19BR. Dicamba (a chlorinated herbicide) was detected above the PQL in the <br />sample collected from AMW-4, and sulfide was detected above the PQL in the sample <br />collected from well AMW-10. Confirmation samples will be collected for each COC <br />DA2008 OO10\FA 2QO8.doc <br />13 Geologic Associates <br />