Remedy chosen for TNT washout facility contamination

Published April 29, 2015
One of the buildings within the boundary of the former TNT washout plant at the Savanna Army Depot, Illinois.

One of the buildings within the boundary of the former TNT washout plant at the Savanna Army Depot, Illinois.

A remedy has been selected for the former trinitrotoluene (TNT) washout facility and adjacent lagoons at the Savanna Army Depot in Savanna, Illinois, where soil and groundwater contamination occurred from washing out bombs and ammunition from 1945 through the early 1970s.

The remedy, selected by the U.S. Army Corps of Engineers the U.S. Environmental Protection Agency, and the Illinois Environmental Protection Agency will allow the 7.5 acre area in the northern portion of Savanna Army Depot to now be used for recreational activities.

“We’ve selected a remedy that will ensure public health and protection of the environment, while allowing the land to be used for recreational purposes,” said Dick Kennard, Louisville District geologist.

Site 1 includes four inactive buildings, which made up the TNT washout facility, where cleaning of bombs, ammunition, and projectiles with high-pressure and high-temperature water took place, and the upper and lower lagoons, which received the wastewater generated from the facility.

Remediation of the soil, surface water and groundwater at the lower and upper lagoons took place in 1991–1995, and there was a focused soil removal near Building 2208 in 2009, but this last remedial action addresses all residual contamination in the soil and groundwater.

The selected remedy for the residual contamination at the site is Monitored Natural Attenuation, meaning natural destructive and non-destructive subsurface attenuation mechanisms will reduce the mass of residual contaminants in the groundwater.

USACE will continue sampling groundwater quarterly with site monitoring wells to ensure that contamination levels are improving. Additionally, there will be five-year reviews and institutional controls implemented, which prohibit groundwater being used as a potable water source and prohibits land use other than recreation. These institutional controls will be in place until the concentrations of hazardous substances are at such levels that allow for unrestricted use and exposure.

“We will follow this site through until it’s deemed safe enough for unrestricted use and exposure,” said Kennard.

Recreational land use will be maintained during and after the transfer of property. The land south of West Road will remain federally-owned and be transferred to the jurisdiction of the U.S. Fish and Wildlife Service; the land north of West Road will be given to the Illinois Department of Natural Resources.