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5. Data Evaluation and Reporting <br /> Water Board staff requested that the ESLs developed by the RWQCB in 2019 be used to guide this VI <br /> assessment until the draft Cal/EPA VI guidance is finalized. ESLs serve as conservative preliminary <br /> metrics for assessing VI based on the measured concentration of a specific VOC in a soil vapor and <br /> indoor air samples. Table 2 presents the soil vapor and indoor air ESLs. <br /> Multiple lines of evidence shall be used to evaluate whether soil vapor may be influencing Site COC <br /> concentrations in the indoor air of each subject building that is sampled.The data evaluation shall <br /> include: <br /> • Observations during the building surveys to understand possible indoor sources of Site COCs and <br /> possible preferential pathways; and <br /> • Comparison of building-specific samples to the applicable ESLs presented in Table 2. <br /> Once the VI pathway evaluation outlined in this Work Plan has been completed, a report documenting <br /> the field methods and results will be prepared and submitted to the Water Board. <br /> It is anticipated that the work described above could be completed according to the following schedule, <br /> assuming availability of laboratory-supplied sampling equipment,subject property/building access, and <br /> that there are no unexpected conditions that may restrict sampling activities: <br /> • Field preparation activities 3 weeks <br /> • Sampling program 4 weeks <br /> • Reporting 8 weeks following receipt of final analytical laboratory results <br /> One round of data shall be collected from each accessed building.Additional sampling events may be <br /> proposed pending analytical results and discussions with the Water Board regarding the results of the <br /> initial event. <br /> 10 "LkLMICH <br />