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Quality Assurance Project Plan for Removal Action <br /> APN 209-450-03,Mountain House,CA <br /> Page 4 <br /> State the problem: The purpose of the sampling program is to determine if the proposed Site is <br /> acceptable for a residential development. Although the proposed development of the Site will result in <br /> asphalt or concrete surfacing over the much of the Site, landscaped areas will include native soils where <br /> resident exposure may occur. Previous investigations have included evaluation of potential contamination <br /> based on historical use of the property. <br /> Identify the Decision: The data obtained from the sampling and testing activities will be used to evaluate <br /> if releases of hazardous substances from historical uses have occurred at the Site. The data results will be <br /> further evaluated to assess the relative threat associated with any found contamination through a screening <br /> risk evaluation. Based on the calculation of human health and ecological risks for the Site, the suitability <br /> of the property for its intended development will be determined. <br /> Identify Inputs to the Decision: Inputs to the decision will include laboratory analytical results of <br /> analytical testing of soils from selected locations on the Site. The soil will be tested for dieldrin as <br /> discussed in Section 2.0 and the RAW. <br /> Define the Study Boundaries: The boundaries of the field sampling and analysis program will be the <br /> perimeter of the Site and waste soil encapsulation area as detailed in the RAW. <br /> Develop a Decision Rule: Decisions will be based on laboratory results for the target constituents <br /> presented in Tables 1 through 3, attached. If no valid detectable concentrations of target compounds are <br /> reported for the collected samples, then a decision will be made that the Site has been adequately <br /> characterized with respect to the Site COC and no further sampling will be required as part of the RAW. <br /> If target constituents are detected in the samples tested, then the data will be evaluated as detailed in <br /> Section 2.2,Data Use. <br /> Specify Limits on Decision Error: The results of analytical testing will be subjected to data validation <br /> on selected data if required by DTSC, as specified in Section 8.3. Data are considered to be valid if the <br /> specified limits on precision, accuracy,representation, comparability, and completeness are achieved. <br /> Optimize the Design: The RAW has been designed to provide the type and quantity of data needed to <br /> satisfy each of the aforementioned objectives. The RAW provides the specifications for the data <br /> collection activities, including the numbers of samples, respective locations and sampling techniques. The <br /> quality of the data will be assessed through the procedures described in this QAPP. <br /> 4.2 PRECISION,ACCURACY,REPRESENTATIVENESS,COMPARABILITY,AND <br /> COMPLETENESS <br /> The basis for assessing the elements of data quality is discussed in the following subsections. In the <br /> absence of laboratory-specific precision and accuracy limits, the QC limits described in this section must <br /> be met or exceeded. Evaluation of selected data will be conducted using the following elements, if, and to <br /> the extent required,by DTSC. <br /> 4.2.1 Precision <br /> Precision measures the reproducibility of repetitive measurements. It is strictly defined as the degree of <br /> mutual agreement among independent measurements as the result of repeated application of the sample <br /> process under similar conditions. <br /> Akk <br /> CONDOR <br />