The Wisconsin Department of Natural Resources (WDNR) will be holding an open house at the Merrimac town hall on January 21 to discuss groundwater contamination in and around the northeast corner of Badger Army Ammunition Plant.  New groundwater monitoring wells installed by the Army in the Weigand’s Bay area have detected explosives above health-based thresholds.

However, according to letters sent to rural Merrimac residents this week “no private drinking water well water samples in the area contained dinitrotoluene (DNT) compounds above or near the associated drinking water standards or health advisory levels.”

CSWAB requested the public meeting to help inform and involve nearby residents.  The community-led group recently submitted formal recommendations to the Army seeking a proactive remedy to assure that additional contamination does not migrate to groundwater and that existing groundwater contamination does not move beyond the plant boundary.

The primary source of contamination from the northeast corner of Badger is the Deterrent Burning Grounds.  This site was used as a demolition debris landfill and for open burning of deterrents, structural timbers, asphalt shingles, and office waste.  Deterrent is an organic liquid containing dibutyl phthalate and DNT used to modify the burning characteristics of propellants.   In 2003 the Army installed a passive bioremediation system to help break down residual subsurface soil contamination and then capped the site.

In other areas around Badger, DNT has moved with groundwater beyond the plant boundary and has contaminated private drinking water wells.  Homes in the Windings of Wisconsin subdivision in rural Prairie du Sac and the Water’s Edge neighborhood on Gruber’s Grove Bay have been affected.  Groundwater monitoring wells have been installed in both neighborhoods and are tested on a quarterly basis by the Army.  The Army also tests dozens of private wells on a regular basis.

Several years ago the Army replaced two private drinking water wells in Water’s Edge when DNT, classified by EPA as a suspected human carcinogen, was found above safe levels.  The new wells are providing safe water for these homes.  However, contaminant levels in groundwater at Water’s Edge continue to exceed health-based standards.  DNT has also been detected in a nearby water well installed by the U.S. Dairy Forage Research Center for its cattle.

The open house will be held on Wednesday evening, January 21, 2009 from 6 to 8 pm at the Town of Merrimac Hall at S6911 State Highway 78 near Merry Mac’s Campground.  The first hour of the open house will be informal.  The Army and WDNR will make a presentation at 7 pm.