Flame retardants: a real danger to wildlife
Flame retardants are added to a variety of products to slow the spread of flames in the event of a fire. They are found, for example, in building materials, plastics, polyurethane-based foams in furniture, textiles, automotive parts, and electronic (your iPhone!) and electrical equipment. < em>Decryption with Jonathan Verreault, full professor at the Environmental Toxicology Research Center (TOXEN), at the University of Quebec in Montreal (UQAM).
ANALYSIS – ; Unfortunately, these standards are often poor predictors of actual fire hazards and too often lead to the unfounded use of these toxic chemical compounds. But that’s another debate…
When people dispose of consumer products containing flame retardants, these chemical compounds end up in the environment and contaminate the wildlife of the St. Lawrence River and its estuary. They can also travel great distances in the air to remote areas, even in the Arctic. As a result, these flame retardant compounds are now found in almost all species studied in the St. Lawrence River.
Using a crossbow, an arrow fitted with a biopsy dart is fired at one of the minke whale's flanks to collect a sample of skin and fat. (Mériscope), Supplied by the author
However, exposure to certain flame retardants in animals is associated with developmental and reproductive disorders and hormonal disruption. Halogenated flame retardants (i.e. those containing bromine or chlorine atoms) are among the most widely used and the most problematic for the environment. Many of them are now banned, such as polybrominated diphenyl ethers (PBDEs), but a new generation of flame retardants replacing them have not been sufficiently tested and are likely to cause similar effects.
Should we be concerned about their impact on the health of wildlife?
As a researcher in ecotoxicology, I devote part of my work to flame retardants in the environment and their impacts on wildlife. I present here a brief portrait of the situation concerning three emblematic species of our region: the northern pike, the minke whale and the beluga.
St. Lawrence fauna highly exposed
When ingested or inhaled, PBDEs accumulate in animal tissues over time. Their concentrations also increase in species that occupy the upper links of the food chain, especially in densely populated, heavily polluted regions.
Hepatic PBDE concentrations four times higher were measured in a predatory fish, the northern pike, exposed to the effluent of the wastewater treatment plant of the city of Montreal, compared to an upstream site in the river. These results highlight the importance of municipal discharges from large urban centers as a source of exposure to flame retardants for river organisms. New flame retardants that have replaced PBDEs, such as chlorinated chemical compounds related to dechloranes, used mainly in the sheath of electrical wires and cables, have also been measured in these same pike.
The research team removes the biopsy from the stinger. (Meriscope), Supplied by the author
A study carried out downstream of major urban centers on the beluga of the St. Lawrence Estuary, a population currently considered to be endangered, revealed concentrations of PBDEs in their blubber among the highest in marine mammals. in the world. Despite the ban on the use of PBDEs for almost 15 years, these concentrations do not seem to be decreasing.
By way of comparison, PBDEs in the fat of belugas have been measured at concentrations about four times higher than in the minke whale, a baleen whale that is a seasonal visitor to the St. Lawrence estuary. A certain number of next-generation flame retardants have also been measured in the fat of belugas and minke whales from the estuary. History seems to repeat itself…
Possible impacts on animal health?
PBDEs are toxic to animals exposed to them. Without confirming causal links, however, studies in wildlife indicate that flame retardants can cause a range of deleterious effects in the body on its hormonal, immune and metabolic functions, and therefore on its growth, reproduction and their development. This is confirmed, at least in part, by studies on the impacts of flame retardants on pike, beluga and St. Lawrence minke whales.
After separating the skin from the fat from the biopsy performed on the whale, the research team processes the samples quickly to prevent their degradation. (Mériscope), Provided by the author
Chez le pike , exposure to flame retardants contained in the effluent of the city of Montreal would have an impact on the regulation of thyroid hormones and certain genes in the liver involved in the metabolism of lipids, important sources of energy for several functions organic.
In belugas and minke whales, exposure to flame retardants, including some emerging compounds, has also been associated with effects on hormones. Links have been established between the concentrations of certain flame retardants such as PBDEs in these two cetaceans and the levels of thyroid hormones and the expression of certain genes playing a key role in the regulation of steroid and thyroid hormones involved in the reproduction and metabolism.
Chemical pollution in these species goes well beyond flame retardants, however, as a complex cocktail of contaminants, whose numbers grow year by year, get accumulate in their tissues, which can create additive or even synergistic effects. Unfortunately, the perpetual cycle of unfortunate substitutions – replacing one toxic compound with one that may eventually be found to be toxic in turn – seems to repeat itself.
And that's not good news for the health of our majestic St. Lawrence River and its precious wildlife.
This article is part of our series< em> The St. Lawrence in depth. Don’t miss the new articles on this mythical river, of remarkable beauty. Our experts look at its fauna, its flora, its history and the challenges it faces. This series is brought to you by The Conversation.
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