Those mussels, oysters and scallops on your plate may come with a secret ingredient: microplastics.
Researchers at Hull York Medical School and the University of Hull in the United Kingdom reviewed more than 50 studies (from 2014 to 2020) to investigate the levels of microplastic contamination globally in fish and shellfish.
The investigators found that mollusks (such as clams, mussels, oysters and scallops) had the highest levels. Mollusks collected off the coasts of Asia were the most heavily contaminated with microplastics. The researchers suggested that these areas are more heavily polluted by plastic.
Scientists are still trying to understand the health implications for humans consuming fish and shellfish contaminated with these tiny particles of waste plastic, according to the report.
"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," said study author Evangelos Danopoulos. He's a postgraduate student at Hull York Medical School.
"A critical step in understanding the full impact on human consumption is in first fully establishing what levels of microplastics humans are ingesting," Danopoulos said in a University of York news release. "We can start to do this by looking at how much seafood and fish is eaten, and measuring the amount of [microplastics] in these creatures."
The research showed that microplastic content was 0 to 10.5 microplastics per gram in mollusks, 0.1 to 8.6 microplastics per gram in crustaceans and 0 to 2.9 microplastics per gram in fish.
The largest consumers of mollusks are China, Australia, Canada, Japan and the United States, followed by Europe and the United Kingdom, the study authors noted.
Plastic waste that ends up in oceans, lakes and rivers can potentially end up inside shellfish, fish and marine mammals. Plastic waste generated worldwide is expected to triple to 155 to 265 million metric tons per year by 2060.
The researchers said more data is needed from different parts of the world to understand how the issue varies between different oceans, seas and waterways. They said there is a need to standardize methods of measuring microplastic contamination so it can be more easily compared.
The report was published online Dec. 23 in the journal Environmental Health Perspectives.
The U.S. National Oceanic and Atmospheric Association has information on ocean pollution.
SOURCE: University of York, news release, Dec. 23, 2020