NEW BRIGHTON, MN, April 17, 2015 -- Today, the city of New Brighton, Minn., announced that a contaminant of emerging concern (CEC), 1,4-dioxane (dioxane), has been detected in trace amounts in some of the city's wells. The likely source of the dioxane is the Twin Cities Army Ammunition Plant (TCAAP), which was identified as the source of other contaminants in New Brighton's drinking water supply.
Earlier this year, the city announced a settlement agreement with the United States Army to continue federal payment of the costs of owning and operating New Brighton's water treatment facility (see "City of New Brighton reaches settlement agreement with Army for WTP funding").
Dioxane acts as a stabilizer in chlorinated solvents, such as trichloroethane and trichloroethylene -- solvents that were used during TCAAP operations. Dioxane was only recently identified as a CEC by environmental and health regulators. Growing scientific knowledge about dioxane and technological advances has led to the ability to detect it at extremely low concentrations.
Thus far, no regulatory limit on the amount of dioxane permitted in drinking water has been set under the Federal Safe Drinking Water Act. However, the Minnesota Department of Health (MDH) has set an advisory limit of 1 part per billion (ppb). Recent testing conducted by the MDH and the city has detected dioxane in the drinking water at levels ranging from 2.9 ppb to 5.5 ppb.
Because the contamination likely originated at TCAAP, the United States Army is required to fund the costs of treatment as part of its settlement agreement with the city of New Brighton.