North End Monitoring & Response Action

The organic compound 1,4-dioxane—or, simply, “dioxane” – is considered a probable human carcinogen by EPA. Used as a solvent stabilizer in the manufacture of chemicals, and present in many current day consumer products like shampoos and detergents as well as commercial and industrial products, dioxane has been detected in groundwater monitoring wells up to 2.4 miles north of Lowry Landfill at concentrations slightly higher than the groundwater standard established for the site of 0.9 parts per billion (ppb), lowered in 2015 from 5 parts per billion (ppb).

Dioxane Risk

The extent of dioxane contamination has been partially determined through a groundwater investigation conducted by the City and County of Denver and Waste Management of Colorado, in cooperation with the U.S. Environmental Protection Agency and other local, state and federal agencies.

Dioxane Cleanup

Since 2007, Denver and Waste Management have implemented a groundwater extraction and treatment response action immediately north of the Lowry Landfill site to minimize the potential for the contaminant to migrate beyond their current location. Several groundwater extraction wells are currently removing contaminated groundwater from the site and transporting it to Lowry Landfill’s onsite water treatment plant via a water pipeline. The treatment plant treats the groundwater, then discharges it to a sanitary sewer system for additional treatment at the Metro and Aurora municipal wastewater treatment plants. Additional extraction wells will be added as necessary.

The ongoing groundwater monitoring since 2007 has shown the dioxane concentrations throughout the groundwater plume have decreased and continue to decline due to the response actions.

Denver and Waste Management continue to monitor groundwater in the area to ensure that extraction and treatment remain effective.

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