Metalworking and foundry operations have been the principal activities conducted on-site from at least 1917 until 2005. Groundwater investigations have shown that groundwater on-site and immediately off-site is contaminated with chlorinated volatile organic compounds (CVOCs), primarily trichloroethene (TCE), tetrachloroethene (PCE), and 1,1,1-trichloroethane (TCA). Clayey and silty regolith and fractured and karstic dolomite bedrock underlay the site. GPI Interim retained Geosyntec to 1) develop a comprehensive understanding of site conditions that influence the fate and transport of contaminants at the site; 2) establish a basis for evaluating practical management controls and assessing the appropriate final disposition of the site, and 3) prepare the site for sale to a new owner for the purpose of redevelopment.
Geosyntec’s Scope of Services
To achieve project objectives, Geosyntec conducted a thorough evaluation of site hydrogeology including the behavior of solvents in the karst aquifer, creek sediments, and surface water. We used the results to prepare a conceptual site model, and negotiate site closure conditions with the Tennessee Department of Environment and Conservation (TDEC) under their Voluntary Cleanup, Oversight, and Assistance Program (VOAP). Following state approval of the proposed environmental management plan, Geosyntec continued to support our client during site demolition by preparing a stormwater management plan, providing on-site health and safety monitoring, providing oversight of demolition contractors, performing maintenance of stormwater management systems, providing remediation oversight for localized areas of contamination uncovered during facility demolition, performing a comprehensive sub-slab vapor survey, and preparing a risk assessment as the final action required to achieve site closure with institutional controls and groundwater monitoring.
Geosyntec gained state approval to install innovative FLUTe® multilevel wells in karst bedrock. Our monitoring data established support for a passive site management plan that included natural attenuation of chlorinated solvents in creek sediment, maintenance of the existing cap to prevent infiltration and leaching of solvents, and institutional controls to limit contact with impacted media and to notify potential site developers of potential environmental liabilities. Geosyntec’s approach achieved state approval as adequately protective of the environment without the need for active groundwater remediation.