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24 May 2021 <br />Project No. 14-3002 <br />Page 11 of 23 <br /> <br />3.0. PCB CLEANUP SITE <br /> <br />Based on data collected from the subject property, the cleanup site areal extent consists <br />of the central and southern portions of AOC2 comprising approximately 50,000 square <br />feet. The areal extent will be re-evaluated and potentially modified following final site <br />characterization. Based on data from AOC1, it is currently not necessary to implement a <br />cleanup of PCB contaminated media. The necessity to implement PCB cleanup in AOC1 <br />may be re-evaluated following final site characterization. <br /> <br />PCB impact does not extend offsite or beyond the property boundary and the cleanup site <br />areal extent is accessible. <br /> <br /> <br />4.0. PROPOSED RISK-BASED PCB CLEANUP LEVELS <br /> <br />Once site characterization is complete and data gaps have been filled, a site-specific <br />human health and ecological risk assessment will be prepared. The risk assessment will <br />be used to determine the cleanup goal and cleanup method proposed for the Site. If a <br />site-specific risk assessment is determined to not be appropriate or necessary, the <br />commercial/industrial RSL of 0.97 mg/kg will be used as the Site cleanup goal. <br /> <br /> <br />5.0. CONCEPTUAL SITE MODEL AND DATA GAPS <br /> <br />Between March 2019 and June 2020, AGI performed two investigations at the subject <br />property to: <br /> <br /> Define and evaluate the extent and characteristics of the NWC and SWC that <br />potentially continued onto the subject property from the adjacent LOF/PNA site to <br />the east. <br /> Locate and identify unpermitted solid waste buried on the subject property and to <br />define and evaluate wastes, if identified. <br /> Determine if historical property use had adversely affected the surface or <br />subsurface of the Site. <br /> <br />During the two site investigations: a total of seventy-nine (79) soil borings (B1 through <br />B79) were advanced to total depths between 2 feet and 20 feet bsg; four (4) monitoring <br />wells (MW-1 through MW-4) were installed to 20 feet bsg; eleven (11) separate surface <br />samples (SS-1 through SS-11) were collected, in addition to the 31 surface samples <br />collected at boring locations; and two (2) concrete samples were collected. A total of 177 <br />soil and waste samples were collected from the borings; four (4) soil samples were <br />collected from the monitoring well pilot borings; and 16 groundwater samples were <br />collected. Soil, waste, and groundwater samples were analyzed for selected COCs, and <br />the additional analytes discussed in Section 1.2. Soil boring and monitoring well logs are <br />provided in Appendix F.