CHASING THE PLUME: ENVIRONMENTAL IMPACTS OF THE GOLD KING MINE SPILL

Historic mines pose a threat to the water quality and environmental health of the surrounding and downstream areas. Metals and contaminants from abandoned mines and their adits, tailings, and waste rock piles serve as a constant influence on the water and sediment quality. During a U.S. Environmental Protection Agency investigation on August 5, 2015, millions of gallons of wastewater were released from the Gold King Mine into Cement Creek, a tributary of the Animas River. The contaminated wastewater flowed downstream into the San Juan River and continued into the Colorado River. These streams and rivers provide drinking water for the southwestern states and are also used for recreation and irrigation. The torrent of wastewater, which EPA reports contained arsenic, cadmium, lead, and mercury, deposited fine orange sediment up to 50 miles downstream. We collected sediment samples from twelve locations along the banks of the San Juan River, Animas River, and Cement Creek one week after the spill. We subsequently performed sequential leaching experiments (Tessier et al., 1979) and the EPA’s Synthetic Precipitation Leaching Procedure (Method 1312). These leaching experiments will reveal how the sediment will behave in the environment after deposition, as well as the mobility of contaminants from the sediment. Leachate from these experiments has been analyzed for trace metals using ICPMS. The mineralogy of the sediment was determined with XRD. The results from this investigation will help determine long-term implications of the spill.