Highest levels of microplastics found in molluscs, a new study reveals

The delicious molluscs and other shellfish dishes that many of you enjoy devouring may not be as healthy as you think.

Research led by a team of researchers at Hull York Medical School and the University of Hull has revealed that mussels, oysters and scallops possess the highest levels of contamination due to the presence of microplastic among all seafood.

The conclusion has been derived from more than the fifty studies conducted by the researchers between 2014 and 2020 to globally investigate the

levels of microplastic contamination in fish and shellfish.

Scientists are still trying to understand the health implications for humans consuming fish and shellfish contaminated with these tiny particles of waste plastic, which thanks to the polluters, finds its ways into waterways and oceans through waste mismanagement.

According to the study author, Evangelos Danopoulos, a postgraduate student at Hull York Medical School said: "No-one yet fully understands the full impact of microplastics on the human body, but early evidence from other studies suggest they do cause harm.

"A critical step in understanding the full impact on human consumption is in first fully establishing what levels of microplastics humans are ingesting. We can start to do this by looking at how much seafood and fish is eaten and measuring the number of MPs in these creatures."

The study shows microplastic content was 0-10.5 microplastics per gram (MPs/g) in molluscs, 0.1-8.6 MPs/g in crustaceans, 0-2.9 MPs/g in fish.

The latest consumption data in the research shows China, Australia, Canada, Japan and the US are amongst the largest consumers of molluscs, followed by Europe and the UK.

Molluscs collected off the coasts of Asia were the most heavily contaminated with researchers suggesting that these areas are more heavily polluted by plastic.

"Microplastics have been found in various parts of organisms such as the intestines and the liver. Seafood species like oysters, mussels and scallops are consumed whole whereas in larger fish and mammals only parts are consumed. Therefore, understanding the microplastic contamination of specific body parts, and their consumption by humans, is key," Evangelos Danopoulos added.

The research, in conclusion, points to the need to standardise methods of measuring microplastic contamination so that different measurements can be more readily compared. Researchers also opined that more data is required from different parts of the world to understand how the issue varies between different oceans, seas and waterways.

Earlier, another study by the University of Bayreuth, led by Prof. Dr Christian Laforsch had revealed the presence of microplastics in mussels. Published in their journal " Environmental Pollution", the Bayreuth team shared the research results from their investigation on the microplastic load of four mussel species which are particularly often sold as food in supermarkets from twelve countries around the world.

According to the journal, the microplastic particles detected in the mussels were of a size of between three and 5,000 micrometres, i.e. between 0.003 and five millimetres.