Mount Polley Mine Leak May Affect Salmon Run

BRITISH COLUMBIA—A tailings pond breach at British Columbia’s Mount Polley Mine, on August 4, set loose 10 million cubic yards of water contaminated with arsenic and mercury and 4.5 million cubic yards of tiny silt silicates into Hazeltine Creek and Quesnel Lake. A salmon run begins in the next few weeks that the Department of Fisheries has predicted could hit historic highs. Two weeks ago, Dr. Carl Walters, a University of British Columbia fisheries school scientist, said he thought sockeye salmon, the most significant species in the run, would not be affected. He said the waste silicates would sink to the bottom or be carried out of the system quickly. However, after discussions with scientists in the field about currents and layered water temperatures in the Quesnel waterways, Walters had second thoughts about the threat to the salmon run from the release of wastes from the mine.

The contaminated water is sandwiched between a warm upper layer and a colder bottom layer of clean water. Three possible scenarios could make conditions worse for the salmon. Seasonal prevailing winds could push surface waters around and release contaminated water. Copper contamination could impair the salmon’s navigational sense of smell. An area of the bottom of the lake is shallow. The interflow of the waters is being monitored by federal and provincial authorities. Monitoring is about all that can be done at this point: Salmon, weather, water and contamination are already in play.