The U.S. Army Corps of Engineers (USACE) Louisville District hosted a public meeting Jan. 9 to share the proposed remedy at the former Nike SL-10 launch area—a formerly used defense site (FUDS) near Marine, Illinois.
The Corps’ recent remedial investigation concluded that there is a small groundwater contaminant plume remaining in the southwest corner of the site, which are assumed to have originated from the former missile assembly building where solvents were likely used.
"Remedial action must be taken to protect human health from exposure to site-related contaminants of concern in the groundwater at the site," said Karen Rabek Louisville District geologist.
The site, which was used during World War II for Nike Hercules surface-to-air missile systems, became excess in 1968 when the mission ended. As part of the Defense Environmental Restoration Program-FUDS cleanup program, USACE manages the cleanup at properties where there is Department of Defense generated contamination.
The recent feasibility study, which evaluated the cleanup alternatives against nine different criteria ranging from cost, short-term effectiveness, and even community acceptance, found the best remedy for the site to be Monitored Natural Attenuation (MNA) and Institutional Controls (ICs).
"This proposed remedial action provides protection of human health and the environment while having the lowest impacts to workers and the environment," said Rabek.
"Since the groundwater contamination is currently stable, and possibly even shrinking due to naturally-occurring processes, the recommended remedy of monitored natural attenuation was proposed," said Rabek. "We will conduct groundwater monitoring to verify that contaminants of concern concentrations continue to decrease, that the plume does not appreciably expand, and that natural attenuation processes remain effective."
ICs are administrative and legal land use controls that place limitations on what activities can take place on a property and thereby limit exposure to site contamination.
"The IC recommended for the onsite property is an environmental covenant restricting onsite groundwater use until groundwater remedial goals are met," said Rabek.
USACE will incorporate any comments received during the public comment period into the Decision Document which will be finalized in spring 2017.