Authors: Scott Roberts*, Mountain Studies Institute, Michael Thomas Bogan, University of Arizona
Topics: Water Resources and Hydrology, Hazards, Risks, and Disasters, Environmental Science
Keywords: Benthic macroinvertebrates; Water quality; Mine remediation
Session Type: Poster
Start / End Time: 5:20 PM / 7:00 PM
Room: Napoleon Foyer/Common St. Corridor, Sheraton, 3rd Floor
Presentation File: No File Uploaded
Chronic or episodic acid mine drainage can have significant negative impacts on freshwater ecosystems. In 2015, the Gold King Mine release caused a plume of mine wastewater to flow into the Animas River near Silverton, Colorado. The release resulted in a severe, but brief spike in metal concentrations in the Animas River, raising concerns about potential impacts to aquatic life, including benthic macroinvertebrates (BMI), which are widely used as indicators of water quality. Using BMI data collected before (2014) and after (2015-16) the release, as well as upstream and downstream of the release point, we examined whether exposure to the plume of mine wastewater caused changes in overall BMI community composition and the metal concentrations in BMI tissue. The concentration of copper in BMI tissue samples was higher after the release, but lethal or sublethal effects associated with this increase in copper concentrations were not evident in community samples. At 1-week, 2-months, and 14-months following the release, we found no evidence that the release had any negative impacts to BMI community composition nor did the release result in the extirpation of metal-sensitive species. These findings should be interpreted within the historical context of contamination in the Animas River, where high metal concentrations from natural and mine-related sources have degraded water quality for decades. If aquatic life in the Animas River had not already been affected by long-term exposure to metals, we may have observed a greater impact from the 2015 Gold King Mine release.