Evidence of long-range transport of selenium downstream of coal mining operations in the Elk River Valley, Canada

Environmental Science and Technology Letters
By: , and 

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Abstract

Expanding coal-mining operations in the Elk River Valley (British Columbia, Canada) have increased total selenium (Se) concentrations in the transboundary Lake Koocanusa (Canada and United States), but the spatial extent of Se transport from the Elk River Mines is unknown. We evaluated multiple lines of evidence of long-range transport of Se at five sites downstream of the mines relative to a site unaffected by the mines. First, all mine-affected sites had increasing trends in flow-normalized Se concentrations between 2005 and 2021 (35–89%), while no trend was observed at the unaffected site between 2005 and 2017. Second, all mine-affected sites had elevated annual mean Se concentrations and 5-year mean annual loads (2013–2017) by up to an order of magnitude relative to the unaffected site. Third, Se concentrations and the magnitude of the concentration trend generally decreased with distance downstream from the mines while loads increased, which is consistent with the downstream transport of the bulk of the Se load from the mines with smaller contributions from other sources. These results provide multiple lines of evidence that Se from the Elk River Mines is transported over 575 river kilometers and may pose risks to aquatic life in the transboundary Columbia River.

Publication type Article
Publication Subtype Journal Article
Title Evidence of long-range transport of selenium downstream of coal mining operations in the Elk River Valley, Canada
Series title Environmental Science and Technology Letters
DOI 10.1021/acs.estlett.4c00222
Edition Online First
Year Published 2024
Language English
Publisher American Chemical Society
Contributing office(s) Colorado Water Science Center, New Mexico Water Science Center, WY-MT Water Science Center, Dakota Water Science Center
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