It is essential to achieve the energy transition, but for that it is necessary to develop a significant amount of minerals and “green” electricity, such as hydropower. These activities often take place on indigenous lands and have environmental consequences for our lakes and rivers.

To achieve the energy transition, new infrastructure is also needed, including the development of a global fleet of electric vehicles and the installation of large wind farms and solar panels. This is already leading to a high demand for minerals, mainly metals, which are now considered critical and strategic.

Our Lakes: Their Secrets and Challenges is a series produced by La Conversation/The Conversation.

This article is part of our series Our Lakes: Their Secrets and Challenges. This summer, The Conversation invites you to take a fascinating dive into our lakes. With magnifying glasses, microscopes and goggles, our scientists will investigate the biodiversity of our lakes and the processes that take place within them, and tell us about the challenges they face. Don’t miss our articles on these incredibly rich bodies of water!

Given the national interest in establishing a stable supply of metals and minerals in a complex geopolitical context, many mineral-rich countries will want to encourage the development of new mines. In Canada and Quebec, these mines are often spread across the Canadian Shield, extending to the Far North, to areas already vulnerable to climate change.

For example, studies are being conducted in the North for several mining projects for rare earth metals. The first operational mine for these metals opened in 2021 near Great Slave Lake in the Northwest Territories. Similar projects are being developed in Nunavik.

Lakes in mining areas receive important and strategic metals, about which little is known at an ecotoxicological level.
(Maikel Rosabal), Provided by the author (no reuse)

Whether through mine tailings or atmospheric deposition, these mines can release a cocktail of metals into the region’s aquatic ecosystems. Often, it is not the mineral of interest that is of greatest concern, but another metal that is accidentally mined. This is the case with radioactive metals such as uranium and thorium, which are often mined at the same time as rare earths.

A glaring lack of data

Several of these metals have not yet been properly studied in terms of ecotoxicology, complicating the work of governments that have to establish water quality criteria with very little data at their disposal.

Researchers and Inukjuak community members collect samples of sentinel organisms
Researchers and members of the Inukjuak community collect samples of sentinel organisms near a new power plant.
(With thanks to Mariane St-Aubin), Provided by the author (no reuse)

As professors of biological sciences at the Université de Montréal and the Université du Québec à Montréal, respectively, and experts in water quality, we are involved in generating the toxicological data needed to establish these criteria. For example, in a recent study, we measured the concentrations of rare earth elements naturally present in water and animals, to document the effects of opening new mines.

We are also developing tools for early detection of the impact of critical and strategic metals on ecosystems. For example, we recently used aquatic insect larvae and zooplankton as a means for environmental monitoring of rare earth elements.

In these studies we have found that it is often the free ionic form of the metal that best explains its accumulation in animals, especially if we take into account other ions in the solution that may compete with the free ion at the site of metal entry (for example at the gills of invertebrates).

Insect larvae can serve as warning signals for metal pollution.
(Thanks to Maikel Rosabal), Provided by the author (no reuse)

These results will enable our government agencies to better predict the impact of future discharges of these increasingly important pollutants.

Hydroelectric power stations on our rivers

In addition, the energy transition will require a large electricity supply that is not dependent on fossil fuels. Hydropower is a popular option, but requires the construction of new power stations on our rivers.

In addition to regularly changing the hydrological regime and biodiversity, these power plants can stimulate the production of a neurotoxin, methylmercury. This production is caused by the activity of microbes that live in oxygen-poor areas, whether it is land flooded by dams or in the sediments at the bottom of reservoirs.

Our recent research shows that even very small power plants, such as river basins, can temporarily increase methylmercury levels in food webs, as well as in large predatory fish and their consumers, including fish-eating birds and humans.

These small power plants account for more than 90 percent of the world’s power plants, but they are rarely studied. Some studies suggest that their cumulative impact could be greater than that of reservoir power plants. We have also found that land disturbances upstream of power plants, such as wildfires and logging, can exacerbate neurotoxin production by facilitating the transfer of mercury and organic matter into rivers.

Partnerships with First Peoples needed

Since these mines and power plants are more often than not located on indigenous lands, it is essential to create trust and communication links with the communities that live there. In this context, we have developed knowledge co-creation research projects in collaboration with First Peoples communities, industry and various universities.

Ecotoxicological research should be conducted in collaboration with First Peoples
Ecotoxicological research should be conducted in collaboration with First Peoples.
(With thanks to Mariane St-Aubin), Provided by the author (no reuse)

These projects encompass the research interests of the communities and the communities receive the research results directly. We use this research framework to promote the transfer of knowledge to communities, for example through knowledge camps where young people are invited to do science with research teams and discover traditional knowledge with elders.

By working with communities, industry and governments, we believe it will be possible to develop inclusive research that can map the impact of the energy transition on our lakes and rivers.