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Focused Groundwater Investigation Work Plan Deuel Vocational Institution(DVI), Tracy, California Data Acquisition and Quality Assurance/Quality Control 5.2.4 Comparability Comparability is a qualitative parameter expressing the confidence with which one data set can be compared to another. Sample data will be collected and reported consistently,to be comparable with other measurement data for similar site samples and sample conditions. This goal will be achieved by using standard operating procedures to collect and analyze representative samples,reporting analytical results in appropriate and consistent units, and meeting similar accuracy and precision acceptance criteria. 5.2.5 Completeness Completeness is defined as the percentage of valid measurements to planned measurements. Valid data are values that are not rejected for any reason, including deviations from QC requirements. An objective of the sampling program is to establish the quantity of data needed to support the investigation. This objective will be achieved by obtaining samples for all types of analyses required at each individual location; a sufficient volume of sample material to complete the analyses; samples that represent all possible contaminant situations under investigation; and samples at critical data locations, such as background and control samples. Completeness will take into consideration adverse environmental conditions and the potential for justifiable change with respect to schedule and sample locations. The completeness goal for this project is 90 percent. 5.3 Quality Control Samples and Procedures 5.3.1 Quality Control Checks The QC checks of both field and laboratory sample analysis will be used to assess and document data quality, and to identify discrepancies in the measurement process that need correction.Field QC samples may consist of field replicates (duplicates),trip blanks, and temperature blank samples. Laboratory QC may consist of method calibration, LCS,method blanks, surrogate spikes, and matrix spike/matrix spike duplicate samples. The analytical laboratory also will report any QC failures, such as calibration check samples that exceed control limits. Field Duplicates FDs will be collected at selected locations to evaluate the environmental variability and precision at a location. The FDs will be handled and analyzed in the same manner as the other environmental samples. FDs will be collected and submitted for analysis at a rate of approximately 10 percent of environmental samples. Temperature Blank A temperature blank is a sample of water provided by the laboratory in a plastic bottle or volatile organic analyte vial,to be shipped in the same cooler as the field samples. The temperature blank should be clearly marked,does not require a sample number or recording on the chain-of-custody form, and should be placed at the top of the cooler for easy access by the laboratory on receipt. Temperature blanks are prepared to enable the analytical laboratory to measure a representative cooler temperature,without having to open a site sample or record a less accurate temperature reading from the air space in the cooler. Temperature blank results are used to assess sample preservation procedures during transportation. One temperature blank should accompany each cooler containing site samples.A temperature blank is applicable only to IDW water samples. 5-2