CSWAB Efforts Lead to New Health Advisories for Explosives in Drinking Water
WISCONSIN - New guidance from state toxicologists will help communities and regulators leverage better cleanup of munitions contamination that poses a risk to drinking water.
On April 4, Wisconsin health officials issued interim Health Advisory Levels (HALs) that are the first federal or state drinking water guidelines in the U.S. for four (4) currently unregulated breakdown products of the explosive DNT.
The new HALs, requested by CSWAB in a formal petition in 2015, may now be used by the state regulators as remediation goals for the protection of groundwater and drinking water resources.
In northern Wisconsin, the DuPont Barksdale Explosives Plant produced TNT, dynamite and other explosives for the military during World Wars I and II, and for the mining industry. Starting in 1997, tests found residues of explosive chemicals including DNT in 17 drinking water wells located between the site and Lake Superior. Health officials said that DNT has also been detected in soils and groundwater at Fort McCoy, an active military installation near Sparta, Wisconsin.
At the former Badger Army Ammunition Plant near Prairie du Sac, Wisconsin, DNT is a principal pollutant associated with four separate groundwater contaminant plumes. The selected remedy for all four plumes is natural attenuation, and degradation is a primary mechanism for achieving cleanup goals for DNT in groundwater.
Of the four new HALs, the lowest is for 2,4-Diaminotoluene at 0.01 parts per billion (ppb) based on cancer risk. By comparison, Wisconsin’s drinking water standard for DNT is five times higher at 0.05 ppb, indicating that the degradation product (2,4-Diaminotoluene) is more toxic than the original parent compound (DNT).
Depending on site conditions, certain forms of DNT may be completely transformed by bacteria to 2,4-diaminotoluene. At Badger, 2,4-diaminotoluene has been detected in groundwater at concentrations as high as 21,000 ppb (April 2003). Its presence is likely resulting from the microbial degradation of residual DNT in soils and groundwater, health officials said.
The three other DNT degradation products have the following HALs: 100 ppb (2-Nitroaniline), 2 ppb (3- and 4-Nitroaniline, combined), and 300 ppb (2,6-Diaminotoluene).
In states that do not have similar drinking water advisories, regulators may now look to Wisconsin’s new advisories for guidance. DNT is a contaminant of concern at dozens of military bases nationwide including Fort Wingate Army Depot in New Mexico, the Joliet Arsenal and Savanna Army Ammunition Plant in Illinois, Camp Edwards in Massachusetts, Weldon Springs Ordnance Works in Missouri, Umatilla Army Depot in Utah, the Hawthorne Army Depot in Nevada, and Radford Army Ammunition Plant in Virginia.
The WDNR does not currently require the Army at Badger Army Ammunition Plant to test private wells or a nearby municipal well for any of the 17 known degradation products of DNT because off-site concentrations of DNT continue to be very low, officials said. CSWAB has asked for re-consideration of the decision in light of the new HALs and the recent Army letter on alternatives to private well testing.
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Above update and linked documents are also posted online at: Laura Olah, Executive Director Citizens for Safe Water Around Badger (CSWAB) Coordinator, Cease Fire Campaign E12629 Weigand’s Bay S, Merrimac, WI 53561
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