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Table 6 <br /> Summary of Laboratory Quality Assurance Notations <br /> ARCO Service Station No. 5469 <br /> .130 S. Wilson Way <br /> Stockton, California <br /> Based on the review of the electronic and hardcopy data (chain-of-custody records, blanks, dilutions, <br /> holding times, LCSILCSD results, MS/MSD results, and surrogate recoveries), the data are acceptable as <br /> reported by the laboratory with the following limitations: <br /> 1. The elevated reporting limits were due to dilutions performed by the laboratory in order to quantitate a <br /> target analyte. <br /> Sampled on January 14, 2003 <br /> 2. The reported results for TPHG in samples MW-4 and MW-5 are due to chromatographic peaks <br /> present in the gasoline quantitation range, however, the peaks present do not resemble the pattern for <br /> gasoline. <br /> 3. The reported results for TPHG in samples MW-6 and MW-10 are due to a discrete peak at C6-C7 <br /> (probably MTBE). <br /> 4. The reported results for TPHG and BTEX in samples MW-1, MW-6, and MW-7, and for dissolved <br /> oxygen and oxygen/reduction potential in all samples may be biased low since the analyses for these <br /> analytes were performed beyond the USEPA recommended holding times. <br /> 5. The reported results for ferrous iron in sample MW-4 should be considered estimated and the <br /> detection limits for ferrous iron in all other samples have been rejected due to a very low average <br /> percent recovery reported in the associated MS/MSD analyses. <br /> Sam led on Februa 12 2003 <br /> 6. The reported results for ethanol and TBA in samples MW-5, MW-7, and MW-8 may be biased low <br /> because the associated continuing calibration standard was outside of acceptance criteria. <br /> 7. The reported results for the USEPA Method 8260B analysis in sample MW-5 may be biased low since <br /> the analysis was performed 1 day beyond the USEPA recommended holding time of 14 days. <br /> 8. The reported result for MTBE in sample MW-5 should be considered estimated due to a high relative <br /> percent difference reported between the associated LCS and LCSD. <br /> P:lsp-Arco for URS154691Quarterly120031Arco_5469_1 Q03.doc 5 TRA TU5 <br />