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Sampling and Analysis Plan for Phase II Environmental Site Assessment South Pointe Property: 701, 705, 833, 855 West Weber Avenue Stockton, California Background May 17, 2021 Soil and Groundwater Sampling WKA collected 259 soil samples across the site and the adjacent Promenade property. Shallow groundwater was encountered at depths ranging from 8 to 17 ft bgs in 12 of the exploratory test pits and at each of these pits a grab groundwater sample was collected. Soil and groundwater samples were analyzed by a California-certified analytical laboratory for one or more of the following groups of analytes: • Total petroleum hydrocarbons (TPH)quantified as gasoline, diesel, motor oil, hydraulic oil, mineral oil, and kerosene by USEPA Method 8015M; • Volatile organic compounds (VOCs) by USEPA Method 8260B; • Semi-volatile organic compounds (SVOCs) by USEPA Method 8270C; • Organochlorine pesticides (OCPs) by USEPA Method 8081A; • Polychlorinated biphenyls (PCBs) by USEPA Method 8082A(soil only); and • Title 22/CAM 17 Metals by USEPA Methods 6000/7000. Data Analysis and Findings Soil and groundwater chemical data were compared to various risk-based screening criteria, and groundwater chemical data were compared to several sets of then-current screening criteria for both residential and commercial exposure scenarios, as summarized below: • California Human Health Screening Levels (CHHSLs, 2005) established by the California Department of Toxic Substances Control (DTSC); • Preliminary Remediation Goals (PRGs, 2004)established by USEPA Region 9; and • Environmental Screening Levels (ESLs, 2007)established by the San Francisco Bay Regional Water Quality Control Board. Laboratory results revealed elevated concentrations of OCPs, lead, petroleum hydrocarbons, and PAHs in site soils at concentrations exceeding one or more screening levels. Elevated concentrations of OCPs and lead were primarily limited to the western and central portions of the site. Elevated concentrations of petroleum hydrocarbons and PAHs were identified in the northeast portion of the site, overlapping with the adjacent Promenade property. OCP impacts were generally aligned with the historical rail spur and the source was believed to have been the result of previous site industrial activities associated with loading/unloading of agricultural materials along the rail spur, as well as possible application of pesticides for weed control along the spur and around areas of grain milling and storage. MProject No.: 185704833.5.3&5.4 2.3