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3.0 AUSTIN UNIT 3.1 WATER QUALITY MONITORING 3.1.1 Sampling and Laboratory Analyses During the first quarter 2011, depth-to-water measurements were recorded and the Austin Unit's DMP and CAP groundwater monitoring wells were sampled by Del-Tech on between March 18 and 31,2011; domestic wells 7898-A and 8106-A were sampled on February 24, 2011; and surface water stations were inspected and samples were collected from surface water stations ASW-1 and ASW-2 on February 24, 2011. Samples were collected from each sample point with sufficient liquid and submitted to Test America for analysis of the parameters stipulated in RWQCB Order No. R5-2003- 0049. Table 2-1 presents the monitoring schedule and summarizes the analytical methods utilized during the current monitoring period. Water quality samples were also analyzed in the field for dissolved oxygen,turbidity,temperature, specific conductance, and pH and recorded on well data sheets. The groundwater monitoring wells and leachate were sampled in accordance with the sampling and analysis procedures detailed in Appendix B. The well data sheets, raw laboratory data, certificates of analyses, and chain-of-custody records related to the sampling program are included in Appendix C. Field and laboratory analyses are summarized in Tables 3-1 through 3-6. 3.1.2 QA/QC Results The QA/QC program completed for the first quarter 2011 water quality monitoring event at the Austin Unit included analyses of two field blanks,two trip blanks, and seven laboratory method blanks. The trip and field blanks were analyzed for VOCs by EPA Method 8260 and method blanks were analyzed for all required analyses. The results of the QA/QC program indicate that a trace concentration of hexachlorobutadiene was detected in one of the method blanks during the monitoring period,however, hexachlorobutadiene was not detected in any of the primary samples. Review of laboratory analysis dates with the required holding times indicates with the exception of hexavalent chromium in the samples collected from AMW-10, the duplicate sample, and 8106-A, all of the samples were submitted and analyzed within the required holding times during the first quarter 2011. Review of the historical concentrations indicates that it hexavalent chromium is generally not detected in samples collected at wells AMW-10 and 8106-A. Based on the QA/QC results, it is concluded that the laboratory data generated for the first quarter 2011 monitoring period are generally acceptable and the water quality samples collected from the Austin Unit appear to be representative of water quality at the site. D:\201 1_N50TA_1Q1 l.docx 8 Geologic Associates