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1 <br />C <br />carried into the field and delivered with the samples to the laboratory for analysis. The <br />field blank was opened in the field during sample collection. The purpose of the field <br />blank was to detect any influences from the ambient atmosphere on the analytical <br />results. The trip blank remained sealed during the duration of the sampling event and <br />was stored with the bottles used for sampling. The trip blank provided a check on <br />laboratory bottle cleaning procedures, and transportation and handling procedures. In <br />addition, one duplicate sample each was collected from Wells MW -1 and MW -4 during <br />the SWAT sampling event. These samples were labeled XDUP-1 and XDUP-2, <br />respectively. Duplicate samples were used to assess the variability associated with <br />sampling. The field and trip blanks were analyzed for volatile organics by EPA Method <br />624. The duplicate samples were analyzed for the same parameters as the primary <br />samples. Results for field QC samples are included with the analytical results for the <br />primary samples (Tables 3, 4, and 5). No volatile organic compounds were detected in <br />either the field blank or the trip blank (Table 3). Results for the primary and duplicate <br />samples were in good agreement (Tables 3, 4, and 5). <br />The laboratory QC samples included laboratory blanks, surrogate spikes, matrix spikes, <br />and matrix spike duplicates. Analysis of laboratory QC samples is routinely performed <br />as part of the required EPA analytical procedures. Laboratory blanks are analyzed to <br />assess the effect of laboratory environment on the analytical results. Surrogate spikes <br />are used to measure the efficiency of the analysis and are therefore good indicators of <br />data quality. Matrix spikes are used to measure how the sample matrix affects the <br />analysis, while matrix spike duplicates are used to determine the reproducibility of the <br />analytical method. Laboratory QC results were generally provided by the laboratory <br />and are sunnnarized below. <br />Laboratory QC results were submitted to EMCON along with the analytical results for <br />the soil sample from MW -3. A laboratory blank for EPA Method 624/8240 analyzed on <br />May 16, 1988 contained 33 micrograms per kilogram (ug/kg) of acetone and 24 ug/kg <br />of methylene chloride. A laboratory blank for EPA Method 625/8270 analyzed on May <br />26, 1988 contained 400 ug/kg of bis (2-ethylliexyl) phthalate. The recoveries for <br />surrogate spikes, matrix spikes, and matrix spike duplicates were within the limits <br />established by the laboratory. Relative percent difference (RPD) values did not exceed <br />8 percent. <br />STL 9390314 1 <br />