The project consists of the following activities to address impacts to soil and groundwater from previous operations at the Former Salinas Manufactured Gas Plant Site. (Site): targeted treatment of deep impacted soils using in-situ stabilization (ISS); capping; confirmation soil and soil gas sampling; institutional controls in the form of a land use covenant (LUC);. and groundwater monitoring. Project activities are detailed in the Remedial Action Plan (RAP). The soil at the Site is impacted by benzene ethylbenzene, polycyclic aromatic hydrocarbons (PAHs), antimony, arsenic, cadmium)· lead, mercury, and petroleum hydrocarbons including visible oil and coal tar residues. The Department of Toxic Substances Control (DTSC) is approving the RAP pursuant to regulatory authority granted under Chapter 6.8, Division 20, section 25356:.1, California Health and Safety Code (H&SC).
ISS will be applied to approximately 1-4,361 cubic·yards (CY) of in-place subsurface soil-. Approximately 4,308 CY (294 truckloads) of excess soil generated from the ISS operation will be disposed at an off-site permitted landfill. The Site surface will be restored to its existing grade and drainage patterns, then capped at the end of the project with either asphalt pavement, concrete and/or crushed rock. Institutional controls in the form of a LUC will be placed on all parcels comprising the Site to prohibit on-site-use of groundwater, limit activities that could damage or penetrate the cap, and restrict sensitive land uses (e.g., single family residences, schools, day care centers) because residual impacts will continue to exist in the soil and groundwater that are above levels acceptable for unrestricted use of the Site. In· addition, a network of.groundwater monitoring wells will be installed and sampled for a minimum period of three years following completion of remediation.