Research suggests that the contamination of Isle of Man seabed sediments with zinc, lead and copper from the mining of these metals, which peaked on the island in the late 19th century, is causing the shells of king scallops to become significantly more brittle.

The research, led by an interdisciplinary team at the University of York, suggests that the contamination of seabed sediments with zinc, lead and copper from the mining of these metals, which peaked on the island in the late 19th century, is causing the shells of king scallops to become significantly more brittle.

The thinning and weakening of shells threatens the species by leaving them more exposed to the crushing claws of crabs and lobsters, and, in turn, threatens the marine ecosystem because of the important functions, such as water filtration, that molluscs like scallops carry out.

Given that metal contamination is common in many coastal areas around the world, the researchers are concerned that other species of marine mollusc like mussels, oysters and clams, which together provide more than a quarter of the world’s seafood, may be similarly affected.

The current consensus on acceptable levels of metal pollution should be revised, the researchers say, as evidence of damage to scallop shells was present even in areas with metal contamination levels currently not thought to cause significant damage to the marine environment.

Lead author of the study, Dr Bryce Stewart from the Department of Environment and Geography at the University of York, said: «The fact that comparably low levels of heavy metal contaminations appear to affect shell structure and strength in such a potent way represents a challenge to marine species management and conservation strategies. This is particularly true given that the effects we observed are likely to be amplified in the future by ongoing human activities and climate change.

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