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10 June 2019 <br />AGE Project No. 14-3154 <br />Page 2 of 3 <br />On 15 April 2019, verification samples were collected from thirteen (13) locations within <br />the excavation area (VS-1 through VS-13) under the oversight of Central Valley Regional <br />Water Quality Control Board (RWQCB) and EHD staff. The results of the verification <br />samples analyses indicated that all contaminants of concern (COC) were below the <br />appropriate screening levels. Except for arsenic, all COC concentrations were below the <br />January 2019 California RWQCB Environmental Screening Levels (ESLs) for <br />commercial/industrial and residential shallow soil exposure. Arsenic was detected below <br />the November 2018 Environmental Protection Agency (EPA) Region 9 Regional <br />Screening Level (RSL) for industrial soil and below the established site-specific <br />background concentration of 8.6 mg/kg (Tables 1 through 3). <br /> <br />A substantial remediation effort was performed to remove WU1 on Parcel A and mitigate <br />the known capped landfill area identified. Additionally, a significant quantity of glass waste <br />and soil mixed with glass waste was removed from the area and stockpiled for offsite <br />disposal or potential reuse at the subject property. A considerable amount of time, <br />resources and cost were expended to perform the remediation effort. Additional time and <br />money will also be incurred to characterize the stockpiled materials for disposal or <br />potential reuse. <br /> <br />The WU1 capped landfill area that extended onto Parcel A has been completely removed. <br />Minimal residual surface glass still remains extending to the north from the excavated <br />area to the railroad tracks. The surface glass remaining is mixed in with the top soil and <br />located within the top 12 to 14 inches of the surface. The remaining residual surface glass <br />was observed by EHD and RWQCB staff on 29 March 2019 during a scheduled <br />inspection of the excavation area; and by EHD staff on 09 April 2019 during trenching <br />activities. The remaining surface glass was also referenced in an email received on <br />05 April 2019 from Linda Turkatte at the EHD. <br /> <br />The remaining surface glass is not part of WU1. However, considerable effort was made <br />to remove as much of the surface glass as possible without compromising the railroad <br />tracks, and a significant quantity of it was removed during excavation activities. Safety <br />and feasibility concerns prohibit continued excavation further north due to the presence <br />of the active railroad spur. It is AGE’s opinion that all waste has been excavated and <br />removed from and beyond the boundaries of the known landfill area/capped waste area <br />identified as WU1. The residual surface glass remaining is not part of the capped land fill <br />area. <br /> <br />During meetings with EHD staff on 17 and 28 December 2018, it was agreed that clean <br />closure would be approved for the WU1 area on Parcel A if the remaining portion of WU1 <br />was excavated and removed and verification sample results were below the appropriate <br />screening levels. However, in an email dated 11 April 2019, EHD staff stated that a clean <br />closure letter would not be issued for the WU1 area because of the surficial glass <br />remaining to the north of the excavation area. The statement was further supported in an <br />EHD email dated 12 April 2019.