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These laboratories will perform the analytical testing of the primary and QA/QC samples collected for this Site characterization. The respective Laboratory Project Managers who will report solely to the Partner Project Manager on any and all aspects of the sample analyses. The laboratories will conform to the QA and QC procedures outlined in their respective laboratory QA plan/standard operating procedures. 3.0 DATA QUALITY OBJECTIVES Data quality objectives (DQOs) have been developed to ensure that the objectives of the project are achieved. Specific DQOs have been developed for the following project activities, including: • Sampling of soil, soil vapor and groundwater, including the collection of QA/QC samples, as appropriate; Analysis of soil, soil vapor, groundwater, and QA/QC samples; • Compilation and reduction of data; and • Analysis of data. The DQOs are designed to ensure that the chemical concentrations reported in the soil, soil gas and groundwater samples are representative of concentrations existing in these media at the Site. Representative Field and laboratory data will be obtained through the use of consistent methods for sample collection, preservation, transportation and analysis. Quality control samples for both field and laboratory operations are used as measures to assess the precision, accuracy, representativeness, and comparability of the collected samples. 3.1 Precision Precision is defined as a measure of agreement among individual measurements of the same parameter. Sampling precision may be defined by collecting and analyzing duplicate field samples. However, this can be somewhat difficult to accomplish with soil samples because of the inherent heterogeneity of soils. Laboratory precision may be defined by analyzing duplicate samples (matrix spike/matrix spike duplicate samples for organic analyses). Comparison of duplicate samples is done by calculating relative percent differences between the sample results. The RPD will be calculated as follows: %RPD = 200%x (X2—X1) /(X2 +Xl) where 'X1'is the smaller of the two observed values and 'X2'is the larger of the two observed values. 3.2 Accuracy Accuracy is defined as the degree of agreement of a measurement or average of measurements with an accepted or true value. Accuracy is a measurement of bias in the determination of values and is best established by analysis of blanks, spikes and continuing calibrations. Bias may result from sampling protocols or analytical procedures. While laboratory, field, or equipment blanks may easily reveal a positive bias, a negative bias due to loss of target analytes may be virtually impossible to measure. Field accuracy will be assessed through the analysis of field and equipment rinsate blanks (see Table Al). Analysis of these blanks will monitor errors associated with the sampling process, possible field-related contamination, and sample handling. The DQO for equipment rinsate blanks is that all values are less than Quality Assurance/Quality Control Plan Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number SM14-129814 Docket Number HAS-VCA 14/15-108 August 15,2016 Page 4