The U.S. Army is reporting that all drinking water wells near Badger Army Ammunition Plant continue to test safe. However, recent testing has detected contaminants above health standards in some offsite groundwater monitoring wells, according to a formal review of public records by CSWAB.
Officials with the Wisconsin Department of Natural Resources (WDNR) said that they are aware of the recent test results and have been in discussions with the Army. However, this dialogue has not included affected residents and local municipalities prompting CSWAB to ask that regular public meetings of the Badger Restoration Advisory Board (RAB) be resumed. The Army abruptly suspended board meetings nearly two years ago. RAB members include local town, village, county, state and tribal government, area residents and CSWAB.
On February 12, the Army submitted a formal request to the WDNR asking for approval of a plan for the systematic shutdown of extraction wells at the southern plant boundary that capture groundwater contamination. The shutdown plan will allow the Army to evaluate the southern contaminant plume under natural conditions without the influence of the groundwater pump-and-treat system. The southern plume which contains primarily solvents and the explosive DNT flows from inside Badger to the Wisconsin River near the Village of Prairie du Sac.
In lieu of active treatment, the Army’s plan will rely on the degradation of remaining groundwater contaminants such as DNT to achieve cleanup. Altogether, the WDNR and Wisconsin Division of Health have identified 24 degradation products of DNT. Drinking water wells near Badger, however, are not tested for these compounds. The Army regularly tests the Village of Prairie du Sac Well #3 for all six forms of DNT, for example, but does not test for any of the 24 identified degradation products of DNT.
In late 2013, the Army detected DNT above the groundwater standard in a monitoring well at the Water’s Edge subdivision. WDNR said that the exceedance is in a shallow water table well and that there have not been similar exceedances at depths where nearby residential wells are screened. State law requires that the Army address any exceedances and comply with groundwater standards even if nearby residential wells are unaffected.
CSWAB’s review also found that high levels of ethyl ether have been detected in groundwater at the southern plant boundary. The wells are adjacent to the Settling Ponds which carried sanitary and industrial wastewater to Gruber’s Grove Bay during the Army’s active production years. The detections reported by the Army are in the deeper C and D level monitoring wells. Concentrations of ethyl ether ranged from 1,900 to 7,690 parts per billion (ppb) exceeding the health-based groundwater standard of 1,000 ppb.
This is not the first time that elevated levels of ethyl ether have been detected near the southern plant boundary. Four years ago, in October 2010, the Army detected ethyl ether in groundwater at the Settling Ponds at 4,610 ppb. In a March 13 email to CSWAB, WDNR wrote that the Department and the Army have been looking for the source of ethyl ether and that there is no immediate threat to nearby private wells.
WDNR assured CSWAB that nearby residential wells are tested quarterly however this is incorrect. On September 4, 2013, the WDNR approved the Army’s request to reduce private well testing. Homes on Keller Road in rural Sumpter Township are now tested annually. Homes to the south on County Z are no longer tested by the Army in accordance with the WDNR’s approval.
Ethyl ether is a solvent that was used in the propellant manufacturing process at Badger. The WDNR said that it is an extremely volatile compound that evaporates readily at room temperature and dissolves easily in water. For these reasons, the WDNR believes that the source of the ethyl ether contamination is not the Settling Ponds. The Department said it will continue to monitor the situation and investigate potential sources.
CSWAB has asked that the Army’s risk analysis for possible vapor intrusion into buildings and homes be amended to include ethyl ether, a compound that was not included in the Army’s previous study. In response to CSWAB’s inquiries, the WDNR today issued a fact sheet on ethyl ether.
High Capacity Wells
CSWAB has also asked that the impact of irrigation and other high capacity wells be included in the evaluation of Monitored Natural Attenuation (cessation of active cleanup) as a remedy for groundwater contamination from Badger. WDNR has informed CSWAB that they will not require the Army to test irrigation wells as the use of these wells does not pose a known threat to human health or the environment and the data is not comparable to that from groundwater monitoring wells. However, CSWAB believes this analysis is necessary as high capacity wells may affect groundwater flow patterns and contaminant transport.
CSWAB has already met with and updated the Town of Prairie du Sac board and representatives of the Village of Prairie du Sac on all these issues. Last week, CSWAB updated members of the Badger Oversight Management Commission which includes representatives of the Town of Sumpter, City of Baraboo, Sauk County, Ho-Chunk Nation, U.S. Dairy Forage Research Center and others. CSWAB will also be attending the next regular meeting of the Merrimac town board.