Laserfiche WebLink
' Attachment C: Data Usability Summary and Laboratory Analytical Reports <br /> Preservation and Holding Times <br /> All samples were received at the laboratory within the acceptance temperature criterion of 4+2 <br /> 'Celsius and were analyzed within specified holding times. <br /> ' Reporting Limits <br /> Data reported for this sampling event were reported with the program-specified reporting limits <br /> for groundwater samples. The program reporting limits were used to report data below the <br /> ' applicable action levels. In some cases, the action levels for compounds may be below the <br /> analytical capabilities of the instruments used to determine the concentration of target <br /> compounds in environmental samples. <br /> ' Laboratory Fuel Notes for TPHd Analysis <br /> The laboratory noted that the observed hydrocarbon fuel pattern for TPHd analyses were atypical <br /> ' in MW-7-W-100105, MW-9-W-100106, MWA I-W-100105, and MW-14-W-100105. The <br /> observed sample patterns were not typical of diesel because they eluted later in the diesel-carbon <br /> range, or the reported result was due to individual peaks eluting in the diesel-carbon range. The <br /> samples were also silica-gel cleaned prior to the analysis and TPHd were not detected after the <br /> silica-gel cleanup. This indicates the TPHd result is not likely petroleum in nature and may be <br /> due to some other contamination that elutes within the same carbon range as diesel fuel. <br /> COMPLETENESS <br /> Completeness is defined as the number of valid results (i.e., those not rejected) divided by the <br /> total number rejected. This evaluation of the data against the QC objectives determined that the <br /> percentages of valid data for each method and matrix are 100 percent. <br /> COMPARABILITY <br /> 1 Comparability is defined as the confidence with which one data set can be evaluated against <br /> another. The data evaluation determined that the data are comparable with other laboratory data <br /> for similar samples and sample conditions. The sample collection techniques, EPA test methods, <br /> detection limits, analytical laboratory, units of measure, and sample preparation procedures were <br /> selected to ensure data comparability between sampling events. <br /> SUMMARY <br /> SAIC-Benham's evaluation concluded that all analytical data are usable as qualified for the <br /> purpose of determining chemical concentrations in soil and groundwater collected at the Alden <br /> Park site in Tracy, California. <br /> Data evaluated for this report were qualified E for field duplicate precision and field blank <br /> contamination. Qualified data with applicable reason codes are shown in Table C-1. <br /> Analytical data collected in support of this investigation are considered precise, accurate, <br /> representative, complete, and comparable; and may be used for the intended purposes unless <br /> otherwise noted. <br /> 1 <br /> ' C-4 <br />