hannah Koepnick

Microbial reduction of selenium at the Colstrip power plant

Contaminated seepage from coal ash disposal ponds has impacted nearby groundwater at the coal-fired power plant currently managed by Talen Energy in Colstrip, Montana. One of the contaminants of concern is selenium, an essential trace nutrient that becomes toxic at relatively low levels. Selenium toxicity is especially detrimental to aquatic life; in some cases, selenium-polluted waters have resulted in extinction of local fish populations.

Native microbial communities at contaminated sites often have the capacity to reduce dissolved forms of selenium to the insoluble elemental form, thus removing it from the groundwater. Hannah Koepnick, a graduate student at Montana State University, is researching how differences in microbial communities and biogeochemistry impact rates of selenium reduction in affected groundwater around the Colstrip plant. Learning how site conditions influence selenium removal will enable the design of more effective remediation plans.