WORK PLANS - Laserfiche WebLink

Home Browse Search

®:� Quality Assurance/Quality Control Plan Martin Metals Finishing Inc. (Former) Stockton, California • Laboratory analytical data; and • Laboratory data validation findings. Step 4. Define the Boundaries of the Study. This step defines the boundaries of the study, including the target population, spatial and temporal boundaries, and practical constraints associated with the study. Target Population The target population for the study is sediment within the storm drain, shallow and subsurface soil onsite and along the storm drain and Mormon Slough, and sub-slab and subsurface soil vapor onsite. COPCs include chromium, copper, lead, zinc, and VOCs due to historic plating operations and waste disposal to the storm drain trench and Mormon Slough. COPCs were developed based on the quantified and suspected Site contaminants listed in USEPA's Site Screening (USEPA, 1997) and a comparison of historical analytical results to current screening levels. The following screening levels were identified for use in this project: • DTSC Human Health Risk Assessment(HHRA) Commercial/Industrial Screening Levels (DTSC- SLs; DTSC, 2020)for soils; • The USEPA Industrial Regional Screening Levels (RSLs)for soil will be applied (USEPA, 2022) for constituents with no established DTSC-SL; • San Francisco Regional Water Quality Control Board (SFRWQCB) Terrestrial Habitat Environmental Screening Levels (ESLs; SFRWQCB, 2019) for Mormon Slough samples only; and • Soil vapor screening levels derived using a default attenuation factor of 0.03 and the indoor ambient air screening levels from either DTSC's Commercial/Industrial Air SLs or the USEPA Industrial Air RSLs. The laboratory reporting limits will be sufficiently sensitive to compare results to required screening criteria. Target constituent and required reporting limits are presented in Table C-1. Temporal/Spatial Boundaries and Practical Constraints The sampling described in this QA/QC Plan will be performed over two to three days within the Site boundary, along the storm drain within FIP, and in five shallow transects across Mormon Slough. Step 5. Develop the Analytic Approach. To determine if sediment and subsurface soil represent a risk to commercial users,the soil sample results will be compared to Commercial/Industrial DTSC-SLs or Industrial USEPA RSLs. To determine if shallow soil concentrations represent an ecological risk for off-site ecological receptors, the Mormom Slough shallow soil sample results will be compared to SFRWQCB Terrestrial Habitat ESLs.To determine if soil vapor analytical result pose a risk to MMF building occupants, soil vapor results will be compared to screening levels derived using a default attenuation factor of 0.03 and the indoor ambient air screening levels from either DTSC's CDIM—Fairgrounds Industrial Park Page 5