Science Focus - the home of BBC Science Focus Magazine
Do all fish and shellfish contain mercury? © Getty Images

Do all fish and shellfish contain mercury?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Methylmercury (the form of mercury found in fish) is a powerful neurotoxin, but altering which fish we eat could help reduce our exposure to it.

Asked by: Jack Moore, Frome

Advertisement

Mercury levels in the oceans have tripled since the Industrial Revolution, thanks to mining and the burning of fossil fuels. All sea creatures absorb some of this heavy metal directly, and once it’s in the body there’s no way of getting rid of it. The amount of mercury in fish varies between species. Long-lived predators like tuna and swordfish tend to contain the most, because they also absorb mercury from their prey and they’ve had a long time to accumulate it. The lowest levels are found in short-lived species lower down the food chain, such as oysters and shrimp.


Advertisement

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.

Authors

Dr Helen Scales is a marine biologist, broadcaster and science writer. She is the author of Spirals in Time and The Brilliant Abyss.

Advertisement
Advertisement
Advertisement

Sponsored content