Laserfiche WebLink
<br />How long had dioxane been in the water? <br />While it was first detected in 2015, dioxane has likely been in the water in trace amounts for years. The <br />dioxane was used in operations at the Twin Cities Army Ammunition Plant (TCAAP). Dioxane is an <br />additive to solvents that were used at TCAAP when it was in operation. <br />Why is dioxane only being discovered now? <br />Scientific knowledge and understanding of dioxane has increased in recent years, and the methods <br />available to test for contaminants at extremely low concentrations like dioxane have improved. Also, the <br />interest in dioxane levels has expanded as science has improved understanding of the health risks <br />associated with dioxane. <br />What is the health risk posed by dioxane? <br />According to the fact sheet from the Minnesota Department of Health (MDH), exposure to dioxane over a <br />person’s lifetime could increase the risk of cancer. Please refer to the fact sheets prepared by MDH and <br />the United States Environmental Protection Agency (USEPA), links to which are on the City’s web page <br />at www.ci.saint-anthony.mn.us <br />How significant is the health risk posed by dioxane in St. Anthony Village’s Water? <br />The current concentration falls below the MDH advisory level for municipal water supplies. <br />The MDH has set its 1 ppb advisory level to provide for a risk of fewer than one possible additional case <br />of cancer for every 100,000 people who consume the water over a lifetime. The MDH’s analysis is based <br />on an assumption that each person consumes two liters (a little more than a half-gallon) of water <br />containing 1 ppb of dioxane each day for their lifetime (approximately 70 years). <br />Is there a federal drinking water limit for dioxane? <br />No. Under the Safe Drinking Water Act, the United States Environmental Protection Agency (USEPA) is <br />responsible for setting enforceable limits on the amount of particular substances permitted in drinking <br />water. The USEPA is currently gathering data to assess the prevalence of dioxane in water supplies <br />nationally. <br />Why doesn’t the City’s current water treatment process remove dioxane from the water? <br />The City’s current water treatment plant was designed to remove TCAAP contaminants that were known <br />at the time it was built through use of granular activated carbon (GAC). GAC has an extensive pore <br />structure that captures typical TCAAP contaminants. As the scientific knowledge about dioxane has <br />grown, it has been discovered that carbon does not capture dioxane. <br />What is the city doing to prevent dioxane from becoming a health hazard? <br />The City is in the process of upgrading its water treatment systems so that the levels of dioxane will not <br />reach a level that may present a health risk. An addition to the water treatment facility currently in design <br />will ensure the dioxane stays below the 1 part per billion (ppb) threshold recommended by the Minnesota <br />Department of Health. <br />Until the upgrades to the treatment system are completed, the City of St. Anthony will implement water <br />conservation measures to reduce the risk that dioxane can reach a level that presents a health risk. For <br />the coming months, the city will: <br />o Restrict lawn watering to an odd/even every other day schedule. <br />o The city’s two splash pads will be closed to conserve fresh water. <br />Who is responsible for paying for the upgrades to the water treatment plant? <br />The United States Army is working with the city on design and financing the upgrades to the water <br />treatment plant. The City of St. Anthony has an existing agreement with the United States Army to <br />respond to water issues related to TCAAP.