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SAP/QAPP Addendum Lodi-125 N Stockton Final March 24,2025 3.0 PROJECT DATA QUALITY OBJECTIVES This section describes project tasks and states the problem definition, specifies DQOs and measurement quality objectives,discusses data review and validation,overviews data management,and addresses assessment oversight. 3.1 Project Tasks and Problem Definition The intent of the TBA is to evaluate the Site for potential environmental concerns related to the rezoning of the Site as mixed use.Results of the Phase II ESA TBA Report and associated ABCA(if necessary)will facilitate a more informed decision on the viability of the Site for the proposed reuse.The primary problem is to identify the presence of chemicals related to past operations at the Site at concentrations that present a risk to potential future Site workers or visitors. 3.1.1 Geophysical Survey A geophysical survey will be performed to assess the presence of a UST or backfill materials consistent with a former UST excavation within an area approximately 10 feet by 10 feet.The geophysical survey will be performed using a Geonics EM61 MK2 time-domain metal detector and a GSSI SIR4000 ground-penetrating radar(GPR)with a 350-megaHertz transducer antenna.The purpose of the EM61 survey will be to detect and map possible USTs,vaults, sumps,metallic underground lines,and buried metal within the survey area. The purpose of the GPR survey will be to detect and map possible former backfilled excavations,and buried pipelines and utility lines.The EM61 survey will be conducted along transects nominally spaced 2 feet apart across the survey area. GPR transects will also be conducted along transects nominally spaced 2 feet apart and over detected EM61 anomalies of interest.The recorded EM61 data will be downloaded to a portable computer in the field for preliminary analysis and quality control review in the field. EM61 data will be processed and gridded using Geosoft Oasis montaj software. Seequent Oasis montaj software will be used for overlaying and comparing EM61 and GPR data,mapping interpretations of anomalous features,and creation of final maps.In addition,detectable underground utilities and pertinent surface features will be mapped using differential global positioning system (DGPS).The geophysical survey area is shown on Figure 3. 3.1.2 Hazardous Building Materials Sampling Inside and outside surfaces of the unoccupied office building will be screened and sampled for hazardous building materials that may contain LBP,ACM,and PCBs.The proposed SL for asbestos in building materials at the Site is any material containing more than 1 percent asbestos per Occupational Safety and 9