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Stockton 99 Speedway Quality Assurance Project Plan April 12,2007 Step 5: Develop a Decision Rule: • If the concentrations of COPCs, or other contaminants, at the Site pose an unacceptable risk to human health and/or the environment, then a Removal Action Workplan or Remedial Action Plan will be required to determine what remedial alternative will be implemented. However, if it is determined that there is an acceptable risk to human health and environment, then no further action would be required. Step 6: Specify Tolerable Limits on Decision Errors: • Tolerable limits are evaluated for decision errors to identify acceptable consequences. The possibility of a decision error exists because a parameter of interest is estimated using data that are imperfect. A decision error occurs when the data are misleading, and as a result, the wrong decision is made. The data are subject to different variability at different stages of development, from field collection to sample analysis. The two main components of error are sampling design error and measurement error. Sampling design error occurs when the data collection design does not capture the complete variability within the media to the extent appropriate for the decision. Measurement error is influenced by imperfections in the measurement and analysis system. Error tolerances are described in detail in Section 3 of this QAPP Step 7: Optimize the Design for Obtaining Data: The sampling and analyses plan has been developed to efficiently provide usable Site data. Components of the design include: • Sampling in accordance with EPA SW-846 procedures; • Collecting archive samples that will be analyzed pending initial sample (metals) analyses results; • Locating certain sample points based on Site physical characteristics (e.g., fill and drainage courses); and • Performing data validation procedures. 3.2 Performance Requirements for Laboratory Analyses EPA SW-846 testing methods will be used for laboratory analyses. For metals, EPA Method 60106/7471 will be used to quantify the concentration of CAM 17 Metals in Site soil samples. EPA Method 8260B will be used to quantify the concentration of VOCs in Site soil samples. EPA Method 8015M with silica gel cleanup will be using to quantify the concentration of TPH in Site soil samples, and EPA Method 8081A will be used to quantify the concentration of organochlorine pesticides in Site soil samples. Quaifry_A Lrwcc_Projed_Pian.Final.doc 3-2 The Source Group,Inc.