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1 Figure 6-1). Laboratory analysis, performed by ACZ Laboratory in Steamboat Springs, Colorado <br /> measured total Benzene, Toluene. Ethylbenzene, and Xylene (BTEX) contaminant levels ranging from <br /> no-detect to 9.4 mg/Kg; and measured Total Extractable Petroleum Hydrocarbons (TEPH) contaminant <br /> levels ranging from no-detect to 25,000 mg/Kg (see Table 6-1). No benzene wai detected in the <br /> laboratory analysis of any of the samples. Copies of the analytical laboratory results are included in <br /> ' Appendix A. <br /> Review of analytical laboratory results indicates that the estimated areal extend of subsurface <br /> contamination is approximately 110 feet wide by approximately 90 feet long. The depth of <br /> contamination is unknown, although it is likely that the contamination does not extend much past the <br /> top of the sandstone caprock layer. The estimated areal extent of contamination (including <br /> approximate depths to caprock) is depicted on Figure 6-2. <br /> As previously stated, the petroleum contaminated mine spoils in the fuel spill area are expected to <br /> contain elevated levels of radionuclides, though no radionuclide analysis was performed during this <br /> ' investigation. <br /> 7.0 QUALITY CONTROL (QC) MEASURES <br /> Although there were no formal Data Quality Objectives established for this project. field personnel <br /> ' took replicate direct PID measurements to assure the production of quality data. Proper operation of <br /> the PID was checked using a known concentration of isobutylene gas prior to use. <br /> Seven replicate PID readings were taken during this investigation. This represents approximately <br /> 18% of the total number (39) of field measurements taken. The precision, expre,:sed as Relative <br /> Percent Difference (RPD), of the QC measurements varied from <l% to approximately 10%, with an <br /> ' average RPD of approximately 2% (see Table 7-1). <br /> 1 <br /> 1 <br />