GLOBAL warming could lead to raised levels of toxic mercury in the fish we eat, research suggests.
Increased rainfall and melting snow and ice is expected to increase the flow of organic matter into aquatic ecosystems in large parts of the northern hemisphere.
Research conducted in Sweden predicts this could lead to a sevenfold increase in the mercury content of zooplankton, tiny marine animals at the base of the ocean food chain.
Herald View: Dangers in discarding the monitoring of fish stocks
As the small creatures are eaten, the mercury is concentrated until it reaches high enough levels in large fish, such as cod, to pose a potential risk to human health.
Mercury can damage nerves. Children may be especially at risk from exposure to fish-derived mercury while their brains and nervous systems develop in the womb.
Up to 17 per 1,000 children from subsistence fishing communities in Brazil, Canada, China, Columbia and Greenland have been shown to suffer from mental impairment due to the consumption of mercury-contaminated sea food, according to the World Health Organisation.
In fish and other sea creatures, the metal is present in an organic form called methylmercury.
Herald View: Dangers in discarding the monitoring of fish stocks
The research shows organic run-off linked to global warming is likely to encourage the growth of bacteria, which go on to dominate the aquatic food web. A “heterotrophic” food web based around bacteria generally has more levels of organisms than an “autotrophic” food web founded on microscopic ocean plants.
With a greater number of stages, a heterotropic food web may have the effect of increasing mercury concentrations, experts believe.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereLast Updated:
Report this comment Cancel