CBC News · Posted: Aug 13, 2020 5:34 PM PT | Last Updated: August 13
Original Publication can be found here.
The Mount Polley mine tailings spill that sent more than 24 million cubic metres of mine waste into nearby waterways in 2014 continues to impact lakes, rivers and aquatic ecosystems, according to a new study.
Researchers have been monitoring Quesnel Lake since the spill, which is considered one of the largest environmental mining disasters in Canadian history.
Though samples taken one year after the spill showed the lake waters had potentially returned to their pre-spill state, new information from a three-year study reveals that is not the case; elevated levels of copper and fine sediment have been found in the lake in both the spring and fall.
Turbidity in parts of the lake increases each spring and fall as it mixes up, bringing sediment up from the lake bottom turning the clear-blue lake green in a natural process called turnover, according to lead researcher Ellen Petticrew. She said this raises concerns about contaminants being reintroduced into the water column.
The research team said chronic exposure to elevated copper concentrations can reduce the growth, reproduction and survival of fish populations. Small changes to the colour and clarity of a lake can alter algal communities.
"Copper for aquatic organisms can be, not just toxic, but also has been found to modify some of the ability for organisms to move," said Petticrew.
Trees damaged by the Mount Polley tailings spill. Photo taken Aug. 27, 2014. (Kieran Oudshoorn/CBC)Quesnel Lake flows into the Fraser River and ultimately into the Pacific Ocean. The state of the water in the lake could impact trout fisheries and Fraser River Pacific salmon stocks.
"Inevitably, these spills end up flowing downstream into lakes or the ocean where they can disappear from view, yet that doesn't mean the impact is over," said Hamilton.
Phil Owens, another researcher on the project and a professor of environmental science at UNBC, said this project will help inform what happens with future environmental incidents.
"I think we need to understand what the environmental implications are when a catastrophic incident like this occurs, so that when other ones occur in the future … we have a much better understanding of what the implications are likely to be to aquatic systems."
SALMON BEYOND BORDERS is a campaign driven by sport and commercial fishermen, community leaders, tourism and recreation business owners and concerned citizens, in collaboration with Tribes and First Nations, united across the Alaska/British Columbia border to defend and sustain our transboundary rivers, jobs and way of life.
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