Health & Safety

All Superfund sites include an evaluation of potential threats to human health. This does not necessarily mean that exposures are occurring. While the community of Silverton is not included in the Superfund site, people do use the mining district for recreation. EPA collected data to evaluate possible exposures for a variety of recreational uses—ATV use, camping, hiking, guiding, fishing as well as traditional practices.

Mining operations have greatly disturbed the land, adding to existing highly mineralized conditions in many areas of the site. Mineralized waste rock exposed to air and water causes acidic conditions to mobilize the release of heavy metals to the surrounding environment. These heavy metals have found their way into the Animas River and its tributaries and have traveled farther downstream.

Evidence from the 2015 Draft Baseline Ecological Risk Assessment (BERA) indicates that:

• The benthic invertebrate (small organisms that live in or on the bottom sediments of rivers and streams) community is impaired in most sections of the Animas River, Cement Creek and Mineral Creek. Effects are less severe further down the Animas River but are apparent to Bakers Bridge.
• Water in the Animas River from Arrastra Creek to approximately Cement Creek is likely toxic to all trout species, with the exception of brook trout. Brook trout living in this reach, however, are likely stressed much of the year.
• Metals concentrations in the Animas River below Mineral Creek have eliminated virtually all fish down to Elk Creek and all cutthroat and rainbow trout down to Cascade Creek, where only a small community of brook and brown trout exists. Results also predict fish populations are likely impaired down to at least Bakers Bridge.
• It is unlikely that birdlife or mammal populations are experiencing significant negative effects from metals in the Animas River.