ARCHIVED REPORTS_2006_2 - Laserfiche WebLink

Home Browse Search

v A single sample set was 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, surface water monitoring points, 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. The results of both 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 fourth quarter 2006 water quality monitoring event at the Austin Unit included analyses of four field blanks, four trip blanks, four laboratory method blanks, and one duplicate sample. The trip, field, and laboratory method blanks were analyzed for VOCs by EPA Method 8260 and are included with the laboratory data in Appendix C. The results of the QA/QC program indicate that six VOCs (bromodichloromethane, bromoform, chloroform, chloromethane, dibromochloromethane, and methylene chloride) were detected in the QA/QC field and trip blanks during the fourth quarter 2006 monitoring event. Review of the primary sample results indicates that several of these VOCs were detected in the primary samples collected, and were flagged as suspected laboratory contaminants. Several of these constituents were also detected in the third quarter 2006 monitoring event where BC concluded, during an internal audit, that the suspected laboratory contaminants were the result of contaminated VOA containers. It appears that BC may have provided ATC with several of these contaminated VOAs. Duplicate samples were collected from well AMW-12 and labeled AMW-DUP. Duplicate groundwater results are presented along with the primary data in Table 3-1. Comparison of the primary sample results with the duplicate indicates that with the exception of hexavalent chromium and suspected laboratory contaminants, there was good agreement (within 10%). 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 2006. 3.1.3 Groundwater Elevations and Contours Prior to purging and sampling, each well was sounded for water depth using a weighted electronic sounder, and the static water level was recorded on a well data sheet (Appendix Q. The groundwater elevations were calculated for each well by subtracting the depth -to -water measurement from the top -of -casing reference elevation. The current groundwater elevation data for the Austin Unit are summarized in Table 3-5. DA2003_02hForwardAasNn_06.dod 9 GeoLogic Associates