Brownfield Redevelopment, Boulevards at South Bay — Carson, CA
Tetra Tech is conducting the human health risk assessment at Carson, California, a 157 acre brownfield site. Restoration plans for this former municipal landfill involve development into multiple land uses, including residential, commercial, recreation, entertainment, big-box retail stores, restaurants, and hotels. To accommodate residential use, the former landfill is being developed with a multi-component cap system including an impermeable geomembrane following soil compaction and installation of a landfill gas collection system. For the initial steps of the development, Tetra Tech developed risk-based soil management goals for metals, pesticides, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) to guide removal and re-location of soil covering the landfill. These soil management goals were approved by DTSC and ensured that soil placed above the geomembrane is protective of human health and the environment. Tetra Tech also derived risk-based screening levels for indicator substances and dusts potentially emitted to ambient air during on-site construction activities. These screening levels were derived in consultation with DTSC to be protective of the public, particularly residents, bordering the property. As site development proceeds, Tetra Tech will be in charge of conducting human health risk evaluations for each landfill cell to confirm that air and soil quality is acceptable for on-site and off-site receptors.