ROLE OF FE, MN, AND AL OXYHYDROXIDES IN MOBILIZING METALS RELEASED DURING THE GOLD KING MINE SPILL

On August 5, 2015 an accidental blowout from the Gold King Mine, Colorado resulted in the release of trace elements into the San Juan River watershed. The resulting “yellow” river was caused by oxidized metal laden particles. These particles were deposited along the river as the plume moved downstream. Little is known about the mobilization of these metals through the San Juan River post deposition. The goal of this study is to understand the association of trace elements with iron, manganese, and aluminum oxyhydroxides. We hypothesize that oxyhydroxides play a pivotal role in the mobilization of trace elements and that the role of these sorbents changes seasonally and along the river reach where influences like agriculture can lead to changes in pH, dissolved oxygen, and the presence of competing anions like phosphate and sulfate. The Utah Division of Water Quality has collected surface water along the Utah reach of the San Juan River (Four Corners to Lake Powell) at varying intervals since the spill. Water was analyzed for both dissolved and total concentrations as well as for particle size and shape. A subset of samples were filtered in series and measured for trace elements to understand the association of particle size with different elements. As sampling efforts continue, field parameters such as dissolved oxygen, pH, and conductivity will be measured along the river reach along with sulfide, phosphate, and nitrate. An understanding of the mobility of mining related contaminants in the San Juan River watershed is pivotal for both mitigation attempts and in determining an overall loading history for this system.