USGS scientist and MSU PhD candidate Meryl Storb, is the lead author on a new study linking increased transport of selenium, nitrate, and sulfate into the transboundary Koocanusa Reservoir to the growth of coal mining operations in the Elk River Valley in British Columbia, Canada. The study found that the increased loads and concentrations of selenium and nitrate to be among the largest documented increases found in the primary literature.
The study found that since 1986, selenium concentrations in the Elk River have increased by 585%, or sixfold. High concentrations of selenium are concerning due to the fact that it has a narrow biological tolerance range – meaning there is a small threshold between what is essential and what is toxic. This is particularly important for egg laying organisms such as fish and birds. Selenium can also persist for hundreds of years and is very difficult to remove from the environment.
Data also showed that the nitrate concentration in the Elk River has shown a near 900% increase in the past 43 years. High nitrate levels can have adverse effects on fish and aquatic insects.
The study was reported by the Montana Free Press, which highlighted further concerns around these likely unprecedented increases in selenium and nitrates:
“Montana Fish, Wildlife and Parks has expressed concern that rising selenium concentrations could be playing a role in the recent decline – 50% — of mountain whitefish populations in the Kootenai River. Exceedances in fish ovaries or eggs have also been documented in westslope cutthroat trout, peamouth chub and Northern pikeminnow pulled from Lake Koocanusa for sampling.”
Despite efforts by the mine operator, Teck Resources, to remove selenium from surface water before it flows downstream, selenium concentrations remain high. Further understanding of the groundwater-surface water interaction in the area are necessary to understand if surface water treatment alone can address the issue.