If the chemical stops leaking into freshwater ecosystems, its concentration in some fish species can drop by more than 75 percent.
Canadian Finance Minister Chrystia Freeland’s recently released mandate letter will keep her busy for the foreseeable future.
Prime Minister Justin Trudeau has given her nearly 50 distinct tasks, eight of which relate to climate change. The mandate letter’s preamble — each minister’s letter has the same one — mentions fighting climate change through a “whole-of-government” approach, so expect climate change to be factored into decisions and policies that might not be obviously related to reducing carbon emissions.
An encouraging new experiment hints that cutting off mercury pollution to bodies of water can quickly translate into lower levels of the toxic substance in seafood.
This is according to a new paper, published today in Nature. During the study, conducted over 15 years, scientists intentionally added a traceable form of mercury to a lake and its watershed. They discovered that the new mercury they added quickly built up in fish populations, and then declined almost as quickly once they stopped additions.
IISD undertook a scoping exercise to hear from our staff, civil society, and policy partners about what they see as some of the biggest challenges in charting a path to sustainable food systems in Canada.
IISD recently undertook an exercise to hear from our staff, civil society, and policy partners about what they see as some of the biggest challenges in charting a path to sustainable food systems in Canada. We wanted to know:
To try and answer these questions, we conducted surveys and workshops with IISD staff who have worked on food and agriculture issues, in addition to conducting interviews with 17 academic, government, private sector, and civil society experts.
Our findings revealed that many urgent questions exist regarding the sustainability of Canada’s food systems. In particular, we heard concerns about the sustainability and resilience of Canada’s food supply chains, the critical need for rapid decarbonization in the country’s food and agriculture sectors, and the need to better address equity and justice concerns across Canada’s food systems.
Some examples of questions we heard:
We heard that there are various existing challenges to effective, sustainable food systems policy in Canada: these include, for example, a lack of incentives for sufficient climate action in agriculture, and challenges navigating municipal, provincial, and federal jurisdiction. We heard that there is a need for multistakeholder dialogues to build a shared vision and consensus on sustainable food systems in Canada, as well as for more inclusive policy discussions that highlight sustainability, equity, and justice issues across the food system. The announcement of a Food Policy for Canada and the accompanying Canadian Food Policy Advisory Council represent landmark progress by the federal government, but there is still much work to be done to achieve sustainable food systems transformation.
Despite the valiant efforts of many policy advocates, organizations, and researchers, some sustainable food systems issues and themes appear to lack the attention they require to tackle the scale of the challenge. Below are five examples. One recurring and overarching piece of feedback we heard is a need for an equitable and holistic approach to food systems research and policy development, encompassing healthy people, animals, and ecosystems.
COVID-19 has brought to light systemic issues and gaps in the Canadian food system that need to be addressed. We heard from many that the pandemic exposed major gaps in our food systems, including shocking levels of food insecurity and income precarity, labour force challenges for Canadian farms, the plight of migrant workers and racialized communities working in the food sector, and more. Yet the pandemic has also put a spotlight on opportunities for sustainable food solutions, such as the increased desire Canadians have demonstrated for local food and self-reliance, such as through community gardening and farmers’ markets.
A key challenge for Canada is how to transition to a more equitable and sustainable food system as part of recovering from the pandemic. See our infographic on the impact of COVID-19.
IISD has been actively pushing for governments to adopt green recovery policies in response to the pandemic. In Canada, our president took part in the Task Force for Resilient Recovery, aimed at fostering a recovery that gets Canadians back to work while ensuring the country is competitive, prosperous, and climate-resilient. We also took part in a farmer-focused task force led by Farmers for Climate Solutions, which made robust federal budget recommendations to spur climate action on Canadian farms while supporting farmer livelihoods.
Internationally, IISD has a strong track record of working on issues related to food security, food policy, farmer incomes, and sustainable production. Food and agriculture issues have cropped up across all of IISD’s programs of work. A great example is the Ceres2030 partnership, which brought together IISD, Cornell University, and the International Food Policy Research Institute to provide the donor community with policy options to best direct their investment to move toward a world without hunger while supporting sustainable food systems.
IISD has significant expertise (e.g., on measures and indicators, community tools, financial instruments, etc.) that could be useful to apply to specific food system areas (e.g., risk management strategies, labour displacement, non-market food distribution systems) to address key sustainability and equity food system issues (e.g., reduce environmental footprints, redistribute wealth along the value chain, rethink markets). There is ample opportunity for more collaboration and synergies among IISD programs in Canada to link science to policy-making and increase work on projects that enhance social equity.
We are inspired by the work of many who are tackling Canada’s food system challenges with dedication and tenacity. Here are just a few examples of recent work from leaders in the field that have caught our eye:
Mercury pollution is a major global environmental problem, with small-scale gold mining and coal burning the two biggest sources, but fish can recover quickly when the pollution stops.
Mercury pollution is a global problem. Emissions from gold mining, coal burning, and other industrial processes travel through the atmosphere, eventually falling to Earth as rain or snow. The poison can make its way to fish and the humans who eat them, where it can damage the developing nervous system, causing problems with memory and language in children exposed in the womb.
Mercury pollution remains a problem in many parts of the Great Lakes, but new research from Canada’s Experimental Lakes Area in northern Ontario shows that efforts to reduce the amount of mercury going into a lake can have quick and dramatic effects on the levels of the pollutant in fish populations.
Reducing mercury pollution entering lakes lowers how much harmful mercury is found in freshwater fish destined for consumers' plates.
Reducing mercury pollution entering lakes lowers how much harmful mercury is found in freshwater fish destined for consumers’ plates.
(le français suit)
This is according to a new paper, published today in Nature. During the study, conducted over 15 years, scientists intentionally added a traceable form of mercury to a lake and its watershed. They discovered that the new mercury they added quickly built up in fish populations, and then declined almost as quickly once they stopped additions.
Notably, the fish populations were able to recover from mercury much quicker than previously understood, which suggests that curbing mercury pollution through policy initiatives now will have a rapid and tangible benefit regarding the quality of fish we consume.
The findings provide indisputable, science-based support for necessary regulations on mercury emissions that have been undermined in recent years, especially in the USA. They also support the efficacy of existing and new policies around that globe that seek to curb how much mercury ends up in our environment.
“Showing that reducing mercury inputs to a lake will lower mercury concentrations in fish sounds simple,” said Dr. Paul Blanchfield of Fisheries and Oceans Canada and Queens University and a lead investigator of the Mercury Experiment to Assess Atmospheric Loading in Canada and the United States (METAALICUS).
“But it required a dedicated team effort, including academic, government and NGO researchers from across North America, during the 15-year whole-ecosystem study to arrive at this conclusion.”
The team applied about one teaspoon of a special form of mercury to a lake and its watershed, at a cost of over one million CAD. They were able to measure this mercury as methylmercury in the ecosystem and to track its rapid decline in fish once they stopped adding it to the environment. Methylmercury is a much more toxic form of mercury that accumulates to high concentrations in many freshwater fishes leading to many adverse, and even life-threatening, symptoms in humans.
The study was carried out at IISD Experimental Lakes Area (IISD-ELA) in Ontario, Canada, which is one of the only facilities in the world where lakes and their watersheds can be experimentally manipulated to determine the many ways in which humans are impacting lakes.
“Whole-ecosystem experiments are incredibly powerful because they examine the effects of a single factor at a time and provide solutions to globally-important issues in a real-world setting,” said Dr. Carol Kelly, who has spent decades conducting research on the experimental lakes.
Part of that real-world setting was working with natural fish populations.
“Studying fish only in laboratories was not revealing the full story,” said Lee Hrenchuk, a Biologist with IISD-ELA. “Individual fish retain mercury they have previously accumulated for a long time, and so it could be assumed that decreasing mercury input to a lake might not be very beneficial. However, we discovered that the hatching of new fish into a lower mercury environment was sufficient to lower the mercury level of the population as a whole in a short period of time”.
“The near-term value of reducing mercury inputs to freshwater lakes was not a sure thing, because large masses of old mercury always exist in lakes from decades past,” said Mr. Reed Harris, of Reed Harris Environmental, one of the founders of the study.
“So, it was critical for the experiment that isotopic form of mercury we added could be distinguished from older mercury in the ecosystem.” As new mercury inputs to the experimental lake were increased and then decreased in a controlled manner, the methylmercury in the lake water, surface sediments, invertebrates and fish both increased and decreased quickly. This was true whether the mercury ‘rained’ directly onto the lake surface or entered the lake from the surrounding watershed in streams.
“While mercury exported to lakes from their watersheds may not decline exactly in step with lowering atmospheric deposition rates, this experiment clearly demonstrates that any reduction in the amount of mercury entering lakes will have immediate benefits to fish consumers,” said Dr. John Rudd, former Chief Scientist at the Experimental Lakes Area and a principal investigator on the study.
“Fish is a high-quality protein that is beneficial to many people, providing that it is low in methylmercury.”
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For more information, or to conduct an interview with one of the researchers, please contact:
Sumeep Bath, Editorial and Communications Manager, IISD Experimental Lakes Area
La réduction des apports de mercure dans les lacs réduit rapidement la concentration de mercure dans le poisson que nous mangeons, selon des scientifiques
La réduction de la pollution par le mercure qui pénètre dans les lacs réduit la concentration de mercure nocif qui se trouve dans les poissons d’eau douce destinés aux assiettes des consommateurs.
C’est ce qu’indique un nouvel article publié aujourd’hui dans la revue Nature. Au cours de l’étude, menée sur 15 ans, des scientifiques ont intentionnellement ajouté une forme traçable de mercure à un lac et à son bassin versant. Ils ont découvert que le nouveau mercure qu’ils ajoutaient s’accumulait rapidement dans les populations de poissons, puis diminuait presque aussi rapidement après l’arrêt des ajouts.
Notamment, les populations de poissons ont pu se rétablir de la présence de mercure beaucoup plus rapidement qu’on ne le pensait auparavant, ce qui donne à penser que la réduction de la pollution par le mercure grâce à des initiatives stratégiques aura un avantage rapide et concret sur la qualité du poisson que nous consommons.
Ces résultats fournissent un appui scientifique incontestable à la réglementation nécessaire sur les émissions de mercure qui a été minée au cours des dernières années, particulièrement aux États-Unis. Ils appuient également l’efficacité des politiques existantes et nouvelles qui visent à réduire la quantité de mercure qui se retrouve dans notre environnement.
« Montrer que la réduction des apports de mercure dans un lac réduira les concentrations de mercure dans les poissons semble simple », déclare M. Paul Blanchfield, de Pêches et Océans Canada et de l’Université Queens, et chercheur principal de la Mercury Experiment to Assess Atmospheric Loading in Canada and the United States (METAALICUS).
« Mais il a fallu un travail d’équipe dévoué, y compris des chercheurs universitaires, gouvernementaux et d’ONG de partout en Amérique du Nord, au cours de cette étude de 15 ans menée sur l’ensemble de l’écosystème pour en arriver à cette conclusion. »
L’équipe a appliqué environ une cuillerée à thé d’une forme spéciale de mercure à un lac et son bassin versant, au coût de plus d’un million de dollars canadiens. Les membres de l’équipe ont pu mesurer ce mercure sous forme de méthylmercure dans l’écosystème et suivre son déclin rapide chez les poissons une fois qu’ils ont cessé de l’ajouter dans l’environnement. Le méthylmercure est une forme beaucoup plus toxique de mercure qui s’accumule à des concentrations élevées chez de nombreux poissons d’eau douce, ce qui entraîne de nombreux symptômes nocifs, voire mortels, chez les humains.
L’étude a été menée dans la région des lacs expérimentaux de l’IISD (RLE‑IISD) en Ontario, au Canada, qui est l’une des seules installations au monde où les lacs et leurs bassins versants peuvent être manipulés de façon expérimentale pour déterminer les nombreuses façons dont les humains ont des répercussions sur les lacs.
« Les expériences portant sur l’ensemble de l’écosystème sont incroyablement puissantes parce qu’elles examinent les effets d’un seul facteur à la fois et apportent des solutions à des problèmes d’importance mondiale dans un contexte réel », explique Mme Carol Kelly, qui a passé des décennies à mener des recherches sur les lacs expérimentaux.
Une partie de ce contexte réel consistait à travailler avec les populations de poissons naturelles.
« L’étude des poissons seulement en laboratoire ne révélait pas toute l’histoire, affirme Lee Hrenchuk, biologiste de la RLE‑IISD. Chaque poisson retient le mercure qu’il a accumulé pendant longtemps, et on peut donc supposer que la diminution de l’apport de mercure dans un lac pourrait ne pas être très bénéfique. Cependant, nous avons découvert que l’éclosion de nouveaux poissons dans un environnement contenant moins de mercure était suffisante pour abaisser le niveau de mercure de l’ensemble de la population en peu de temps. »
« La valeur à court terme de la réduction des apports de mercure dans les lacs d’eau douce n’était pas certaine, car de grandes masses d’ancien mercure existent toujours dans les lacs depuis des décennies », explique M. Reed Harris, de Reed Harris Environmental, l’un des fondateurs de l’étude.
« Il était donc essentiel pour l’expérience que la forme isotopique du mercure que nous avons ajoutée puisse être distinguée du mercure plus ancien dans l’écosystème. » À mesure que les apports de nouveau mercure dans le lac expérimental augmentaient, puis diminuaient de façon contrôlée, le méthylmercure dans l’eau du lac, les sédiments de surface, les invertébrés et les poissons augmentaient et diminuaient rapidement. Cela était vrai, peu importe que le mercure soit arrivé directement à la surface du lac ou qu’il ait pénétré dans le lac à partir du bassin versant environnant dans les cours d’eau.
« Même si le mercure transporté dans les lacs à partir de leurs bassins versants ne diminue peut-être pas exactement au même rythme que la baisse des taux de dépôt atmosphérique, cette expérience démontre clairement que toute réduction de la quantité de mercure qui pénètre dans les lacs aura des avantages immédiats pour les consommateurs de poissons », affirme M. John Rudd, ancien scientifique en chef de la région des lacs expérimentaux et chercheur principal de l’étude.
« Le poisson est une protéine de grande qualité qui est bénéfique pour de nombreuses personnes, à condition qu’il soit faible en méthylmercure. »
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Pour obtenir de plus amples renseignements ou pour mener une entrevue avec un des chercheurs, veuillez communiquer avec :
Sumeep Bath, gestionnaire de la rédaction et des communications, région des lacs expérimentaux de l’IISD