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Sampling and Analysis Plan for <br /> Phase II Environmental Site Assessment <br /> South Pointe Property: 701, 705, 833, 855 West Weber Avenue <br /> Stockton, California <br /> Project and Data Quality Objectives <br /> May 17, 2021 <br /> 3.0 PROJECT AND DATA QUALITY OBJECTIVES <br /> 3.1 PROJECT TASK AND PROBLEM DEFINITION <br /> The grantee (City of Stockton) is marketing the 9-acre South Pointe site for redevelopment in accordance <br /> with area zoning requirements and long-range planning efforts. Potential development projects may <br /> consist of high-density residential, mixed use, large-scale commercial offices and office support, tourism <br /> and/or recreational facilities, and government facilities. Previous environmental investigations have <br /> identified the presence of OCPs, lead, and petroleum hydrocarbons in shallow soils beneath the site. <br /> Some compounds, particularly OCPs and lead, are present at concentrations which exceed risk-based <br /> screening levels for residential and/or commercial use. Previous efforts have generally validated the site <br /> conceptual model regarding sources of chemicals (agricultural products loaded/unloaded from rail cars, <br /> and possible historical application of pesticides along the rail line and unpaved portions of the site). <br /> In general, the site has been characterized to a degree that allows reasonable decision-making regarding <br /> future site use and how soil impacts may need to be managed. This investigation intends to address two <br /> key data gaps: <br /> • Incomplete vertical delineation of OCPs in soil. The vertical extent of OCP impacts to soil is <br /> incomplete in several areas of the site. Additional soil sampling will address this data gap. <br /> • The potential presence of VOCs in soil vapor has not been previously addressed. The presence <br /> of VOCs in soil vapor at concentrations that would require remediation and/or mitigation as part of <br /> construction is a potentially a major factor affecting site redevelopment planning. This <br /> investigation proposes site-wide passive and active soil vapor assessment to evaluate this <br /> exposure pathway, and to assess if there are any unknown sources of VOCs at the site. <br /> Collected soil data will be compared to applicable risk-based screening criteria to assess the vertical limits <br /> of OCP-impacted soils possibly requiring removal or management as part of site redevelopment. Soil <br /> samples will also be analyzed for total lead, as elevated concentrations of lead have previously been <br /> identified across the site. Passive soil vapor data will be used to identify areas of VOC mass <br /> accumulations in soil vapor, which will guide subsequent multi-depth soil vapor assessment using active <br /> methods at an estimated ten locations. These data will generate quantitative information on VOC <br /> concentrations in soil vapor, allow assessment of potential onsite sources of VOCs, and provide <br /> information the overall potential risk to future site users due to vapor intrusion. Reported concentrations <br /> will be compared to risk-based screening criteria for assessing potential risk to human health. <br /> 3.2 DATA QUALITY OBJECTIVE ANALYSIS <br /> Following is an analysis of data quality objectives for the proposed Phase 11 ESA. <br /> M <br /> Project No.: 185704833.5.3&5.4 3.1 <br />