Cerium, yttrium, neodymium… Few people know the subtleties of these elements called “rare earths”. Yet these metals are found all around us, in our cell phones, our screens and our cars. Rare in nature as their name indicates, they remain however very little recycled. Voices are being raised for the Horne Foundry, the largest recycler of electronic waste in North America, to monitor the second life of these mysterious atoms.
The Rouyn-Noranda smelter burns approximately 50,000 tons of electronic waste each year in Rouyn-Noranda to extract the already well-known metals, such as gold and copper. This recycling to nearly 1200 ohC of motherboards or old telephones releases significant amounts of rare earths into the atmosphere. These releases worry scientists.
“I have the impression that we are repeating a scenario that we saw before, 70-80 years ago,” drops Yves Grafteaux, director general of the Témiscamingue watershed organization. “We don’t detect them because we don’t follow them. As with traditional metals at the time, there was a lack of information to require a standard. If there is no standard, there is no monitoring. If there is no follow-up, we cannot know if there is an abnormal overshoot. »
At his apolitical body’s annual general meeting last week, pollution from the Horne smelter obviously caught the eye. A team of researchers from the University of Quebec in Montreal (UQAM) presented the pollution blind spots of the plant owned by Glencore.
There is an “invisible contamination”, observes Maikel Rosabal Rodriguez, one of these researchers in ecotoxicology at UQAM.
” [Les terres rares] are heavy metals that sink to the bottom of the water. They are found in sediments, benthic animals [qui vivent sur ou au fond des eaux]but very little in pelagic fish, [en suspension] in the water as such. »
The mixing of water, the rise of these elements in the food chain and the accumulation of these rare earths in the Abitibi soil could perhaps harm the health of residents in the short or long term. But, impossible to predict, because the consequences on human health of these elements in the environment have not been the subject of any scientific study until now, confirms Maryse Bouchard, holder of the Canada Research Chair on environmental contaminants and population health. “If there is, it’s a very new topic,” she said.
Maikel Rosabal Rodriguez is particularly concerned about the concentration of these metals in Lac Dufault, Rouyn-Noranda’s drinking water reservoir. Preliminary data show a higher concentration of contaminants there than elsewhere. “Data is needed to set strong environmental standards. It is necessary,” he insists.
No chemical monitoring can trace a direct link between these samples and emissions from the smelter, but everything points in this direction. Traces of rare earths are found in concentrations up to 11 times higher within a radius of 10 km from the plant than within a radius of 50 km around the metallurgical complex, according to the review by Maikel Rosabal’s team Rodríguez.
Social desirability
Rare earth contamination is “not alarming”, according to preliminary samples from UQAM researchers, but this situation could be set to change. The foundry wants to increase the amount of electronic waste recycled in the coming years.
However, Glencore promises a “major” renovation of its facilities in the coming years in order to limit polluting discharges. Their engineers plan to “encapsulate the entire smelter” Horne to prevent the escape of toxic emissions.
Even if the emissions of rare earths into the atmosphere risk being capped in this way, Maikel Rodriguez sees this as a missed opportunity for the foundry, because these rare earths will still end up in the scrap heap. “Glencore could recycle rare earths and make a profit from it,” he believes.
Above all, Yves Grafteaux sees it as a means of “moving from social acceptability to social desirability”.
“It is possible to go beyond the standards. Many people do this in the mining world. They do it to be well received by the population, to be well received by the population. For the time being, the Horne foundry is under the management of an uncle. They are much more traditional in their way of doing things,” he criticizes.
Quebec has the technology and the knowledge to analyze “almost all the elements of the periodic table of elements”, extrapolates Maikel Rosabal Rodriguez.
The extraction and recycling of rare earths is also part of the Quebec Plan for the Valorization of Critical and Strategic Minerals 2020-2025.