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Data Validation for Soil Samples, Soil Gas Samples and Groundwater Samples Collected from the Tracy Former MGP Site July/August 2008 and April 2009 Summary A total of ninety-three soil samples, nine groundwater samples, and twenty-seven soil gas samples were collected at the Former Tracy California MGP Site at 502 E. Grant Line Road in July/August 2008 and April 2009. The soil and groundwater samples were analyzed by Calscience Environmental Laboratories at 7440 Lincoln Way in Garden Grove, CA. The soil gas samples were analyzed by Air Toxics LTD at 180 Blue Ravine Rd. in Folsom, CA. Completeness for Validated Samples- The samples validated as listed in Table 1 totaled sixteen samples including method blanks. The number of compounds/analytes examined and verified was 879 not including the method blanks. Thirty four compounds/analytes were determined as estimates (Table 2) due to surrogate percent recovery being out of range. The percent completeness for the validated data package was 96%. General Information Data validation is performed to assess the quality of the sample data by the QA/QC criteria using the USEPA Contract Laboratory Program guidelines. Approximately 10% of the data were selected at random to be validated. The data packages for the analyses of the soil and groundwater samples include: analytical results; blank results; surrogate spike percent recoveries and control limits (organic methods only); the laboratory control samples (LCS)percent recoveries and control limits; the matrix spike percent recoveries, and the matrix spike duplicates percent recoveries (MS, MSD) including the control limits; and the relative percent difference of the MS and MSD and the control limits; and duplicates and control limits. Duplicates were validated for a soil (1) and groundwater samples (1). No raw data is included. The data package for the soil gas analyses for volatile organic compounds contained the analytical results, blank results, surrogate spike percent recoveries and the control limits, the laboratory control results of the LCS and the LCSDs including the control limits. Duplicates were run for two samples. No raw data is included. Table 1 shows the assigned Work Number, the analytical methods used for the analyses and the samples that were validated. The LCS results were evaluated by determining if the LCS sample was analyzed on the same day as the samples were run. The percent recoveries were all at or near the 100% recoveries. Table 1 shows the assigned Laboratory Work Number and the analytical methods used for the analyses and the samples that were validated. 1