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groundwater monitoring wells were sampled by Del-Tech between March 29 and 31, 2010. Both surface water stations were sampled on March 31, 2010. 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 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 2010 water quality monitoring event at the Austin Unit included analyses of three field blanks, two trip blanks, one equipment blank, three laboratory method blanks, and one duplicate sample. The trip, field, and equipment 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 low- levels of chloroform, chloromethane, methylene chloride, and toluene were measured in one or more of the QA/QC blanks during the monitoring period. Review of the primary sample results indicates that similar concentrations of toluene were detected in the primary samples collected from well AMW-18 and surface water station ASW-2 and were flagged as suspected field/laboratory contaminants. During the first quarter 2010 monitoring event, a duplicate sample was collected from CAP well AMW-I and labeled AMW-DUP. Duplicate groundwater results are presented along with the primary data in Table 3-2. With the exception of arsenic and vinyl chloride, comparison of the values in the primary sample with the duplicate indicates that there was good agreement(within 10%). Of note, concentrations less than the PQL were not included in the comparison since these are estimated values. Review of laboratory analysis dates with the required holding times indicates that, with the exception of hexavalent chromium for well AMW-2, all samples were submitted and analyzed within the required holding times during the first quarter 2010. The holding time for hexavalent chromium was exceeded by approximately 19.5 hours. Review of the analytical data indicates that the hexavalent chromium concentration measured in well AMW-2 is within the historical range of values measured for this constituent. Based on the results of the laboratory blank and duplicate analyses, it is concluded that the laboratory data generated for the first quarter 2010 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:\2010_0013\FA_IQ10.doc 9 Geologic Associates