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3.0 AUSTIN UNIT 3.1 WATER QUALITY MONITORING Sampling and Laboratory Analyses During the fourth quarter 2012, depth-to-water measurements were recorded on November 14, 2012 and the Austin Unit's DMP and CAP groundwater monitoring wells were sampled by Del-Tech on November 14 and 26, 2012. Surface water samples were collected on December 19, 2012 and a leachate sample was collected on November 27, 2012. Samples were collected from each sample point with sufficient liquid and submitted to BC 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 ORP, 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. QA/QC Results The QA/QC program completed for the fourth quarter 2012 water quality monitoring event at the Austin Unit included analyses of two trip blanks, four laboratory method blanks, and one duplicate sample. The trip 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 no VOCs were detected in trip or method blanks. Inorganic constituents including chloride, magnesium, sodium, iron, arsenic, tin, mercury, potassium, barium, and hexavalent chromium were measured at trace concentrations in method blanks. These constituents were measured at very low concentrations that generally did not affect the interpretation of primary sample results. However, since hexavalent chromium is only detected intermittently at groundwater monitoring well AMW-4 and was detected at an estimated trace concentration during the current monitoring period, it was flagged as a laboratory contaminant on Table 3-1. A duplicate sample was collected from CAP well AMW-19 and labeled AMW-Duplicate. Duplicate groundwater results are presented along with the primary data in Table 3-2. The duplicate sample analyses generally yielded good correlation with most quantifiable constituents having a relative percent difference (RPD)of less than nine percent. Only nitrate (as N) had a higher RPD (22 percent). Review of laboratory analysis dates with required holding times indicates that all samples were submitted and analyzed within the required holding times during the fourth quarter 2012. Based on the results of the laboratory blank and duplicate analyses, it is concluded that generally acceptable QA/QC c:\zotz-ooz5\FA4Qlz.aoc Geo-Logic Associates