Metal pollution in British waters may be threatening scallops, study reveals

November 05, 2020

Metal pollution from historic mining appears to be weakening scallop shells and threatening marine ecosystems in an area off the coast of the Isle of Man, a major new study suggests.

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.

"The potential long-term impact of anthropogenic metal pollution on marine organisms, as shown in our work, is remarkable since the last major mine on the Isle of Man closed in 1908."

Over a period of over 13 years, the researchers compared scallops collected from six areas of the Irish Sea around the Isle of Man. Most scallops exhibited perfectly normal shell growth and strength. However, in one area off Laxey - known to be contaminated with metal pollution, the shells were significantly weaker.

Structural analysis of shells by physicists at the University of York revealed that Laxey scallops had significantly weaker shells and a disrupted shell structure. Lethal damage rates in scallop catches from Laxey were twice as high as those at uncontaminated areas.

Joint corresponding author Professor Roland Kröger, from the Department of Physics at the University of York, said: "We analysed the shell structure of the scallops with cutting-edge microscopy techniques and discovered that shells from Laxey were thinner and exhibited a pronounced mineralisation disruption parallel to the shell surface within the central region of both the top and bottom valves.

"Our data suggest that these disruptions caused reduced fracture strength and therefore could increase mortality.

"It is not clear exactly how metal bearing sediments may be affecting the shell formation process. Metals could be incorporated into shells replacing calcium during the biomineralization process or they may modify the activity of proteins during the crystallisation process and disrupt shell growth."

The researchers looked at a wide range of alternative explanations for the impact on scallop shells but found no other environmental factors that could explain their results.

Dr Stewart added: "While the scallops are still perfectly safe to eat, we believe our results provide a compelling case that metal contamination is playing an important role in the development of thinner and weaker shells at Laxey, and therefore the observed high damage rates.

"The shell characteristics of bivalve molluscs such as clams, oysters, mussels and scallops could potentially function as a good bellwether for the scientific community in assessments of how pollutants are affecting biological organisms."
Metal pollution as a potential threat to shell strength and survival in marine bivalves is published in the journal Science of the Total Environment.

The research was carried out in collaboration with: Bangor University, the Department of Environment, Food and Agriculture, Isle of Man and the University of Liverpool. The project was funded by the European Union, the Isle of Man Government, a Nuffield Vacation Research Bursary and the UK Engineering and Physical Sciences Research Council (EPSRC).

University of York

Related Contamination Articles from Brightsurf:

Sheep show the contamination by microplastics in the agricultural soils of Murcia
A team from the Diverfarming project has found microplastics in 92% of the faeces of sheep fed in intensive agricultural zones of Murcia that they analysed

Velcro-like food sensor detects spoilage and contamination
MIT engineers have designed a Velcro-like food sensor, made from an array of silk microneedles, that pierces through plastic packaging to sample food for signs of spoilage and bacterial contamination.

Avoiding food contamination with a durable coating for hard surfaces
A new study from a team of University of Missouri engineers and food scientists demonstrates that a durable coating, made from titanium dioxide, is capable of eliminating foodborne germs, such as salmonella and E. coli, and provides a preventative layer of protection against future cross-contamination on stainless steel food-contact surfaces.

Using genetically engineered, barcoded microbes to track food contamination and more
Synthetic spores programmed with DNA barcodes provide a highly flexible, high-resolution system for tagging and tracking the provenance of an object.

Study analyzes contamination in drug manufacturing plants
A study from an MIT-led consortium, which analyzed 18 incidents of viral contamination at biopharmaceutical manufacturing plants, offers insight into the most common sources of viral contamination, and makes recommendations to help companies avoid such incidents.

New aflatoxin biocontrol product lowers contamination of groundnut and maize in Senegal
Recently a team of plant pathologists have developed an aflatoxin biocontrol product, Aflasafe SN01, for use in Senegal, which includes four atoxigenic isolates native to Senegal and distinct from active ingredients used in other biocontrol products in Africa and elsewhere.

Contamination by metals can increase metabolic stress in mussels
The researchers propose that this evidence should be used as input to public policy with the aim of mitigating the impacts of human activities on coastal and marine ecosystems.

Radioactive tadpoles reveal contamination clues
Tadpoles can be used to measure the amount of radiocesium, a radioactive material, in aquatic environments, according to new research from University of Georgia scientists.

Radiation contamination at a crematorium
Radioactive compounds known as radiopharmaceuticals are used in nuclear medicine procedures to diagnose and treat disease.

New device simplifies measurement of fluoride contamination in water
Seeking to address fluoride contamination in drinking water, chemical engineers at EPFL have developed a portable and user-friendly device that can measure fluoride concentration accurately and reliably.

Read More: Contamination News and Contamination Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to