U.S. EPA Superfund Optimization Projects, Nationwide


HGL is contracted to conduct optimization reviews in support of EPA’s nationwide strategy to apply Superfund optimization practices at all stages of the CERCLA process, from site characterization through remedy implementation/operation and site completion. Each HGL review is an independent study funded by EPA that evaluates existing data, discusses the CSM, analyzes remedy performance, and provides suggestions for improving remedy efficacy, reducing costs, and achieving remedial action objectives, including site reuse and closure. Recommendations are based on an independent evaluation of existing site information, represent the technical views of the optimization review team, and are intended to help the site team identify opportunities for improvements in the current remediation strategy. Under multiple task orders, HGL SMEs have provided optimization reviews at over 40 sites nationwide, including mining sites, industrial sites, and landfills with a range of contaminants including chlorinated solvents, petroleum hydrocarbons, metals, polychlorinated biphenyl (PCBs), and 1,4-dioxane.

Former Mercury Mining Site, CA
Former Hard Rock Mining Site, ID
Project Highlights
For a 1,500-square-mile former hard rock mining site in Idaho, completed a large-scale monitoring optimization (soil, sediment, groundwater, surface water, biota) and developed recommendations including collecting filtered and unfiltered groundwater samples to adequately represent contaminants of concern (COC) transport and collecting and analyzing major ion parameters (calcium-carbonate, sodium-chloride).
For two former mercury mines in California, conducted an optimization review and identified several data gaps in the CSM, provided specific recommendations on how to address data deficiencies including establishing an online document repository, recommended additional surveying and structural evaluation of mine features and seep flow monitoring, and suggested an update to the CSM using additional biological sampling.
For a former wood treating facility in Arkansas, conducted an optimization review and recommended conducting additional site characterization to delineate source material and the dissolved-phase plume, installing additional groundwater wells to monitor contaminant attenuation and potential migration of contaminants, and implementing institutional controls.
For a 345-acre active landfill site in Washington where chlorinated solvent contamination in groundwater has extended off site, recommended conducting a survey to identify the status of all historical monitoring wells on site and exploring strategies for delisting the site and transferring regulatory oversight to a more appropriate regulatory framework, such as RCRA.