Microplastics in Mussels- Oysters and Scallop

Monikandon Sukumaran*, Kesavan Devarayan and Ramar Marimuthu College of Fisheries Engineering Tamil Nadu Dr.J. Jayalalithaa Fisheries University, Nagapattinam

2021-03-18 10:05:27

Credit: pixabay.com

Credit: pixabay.com

Generally, everyone is well aware of plastics and its disadvantages. Plastics are not biodegradable as natural leaves or natural materials. These plastics break into small pieces of size with less than 5 mm and they are known as microplastics.  By origin microplastics are classified into primary and secondary. Plastic products, household uses of a variety of plastics, construction materials and industrial applications are the primary sources. Secondary sources are those which are formed by fragmentation of these plastics which are discarded into the environment.

Marine and Microplastics

The major source of microplastics in the marine environment is due to the discarding of the plastic wastes into the sea. Once plastics find their way into the water bodies or oceans it ends in microplastic and interacts with the food chain of the marine fishes, crustaceans, bivalves and mammals. Microplastics are found globally in the marine environment and the marine environment is affected by the quantity of microplastics they receive. Marine plastics present in the marine environment time have occupied all the compartments of the marine ecosystem and the food web. These microplastic pollutants are found across the different trophic levels of the marine ecosystem. It includes from the bottom of the marine food to the top level of the trophic level. 

Microplastics and Human health risks

Humans are exposed to microplastics in two ways principally by inhalation and ingestion. If microplastics are present in the atmosphere and inhalation of these particles will occur through the air we breathe. But the possibility for the ingestion of microplastics is only through the food we eat or through the water we drink. 

Generally, food hazards are classified into three categories namely Chemical, Physical, biological and these categories are based on the potential cause to health and its effects. But an unimaginable fact is that currently microplastics is under the above three categories of food hazards. The alarming fact is that globally microplastics are found in commercial seafood species of crustaceans and bivalves. These witnessed that microplastics had already entered into the pathway of human food and the link between microplastics to the human health hazards needed to be immediately assessed.

"If you eat mussels, oysters and scallops you eat microplastics"

A study conducted by University of Bayreuth which was headed by Professor Christian Laforsch, has made the claim that microplastics contamination is found in the mussels and scallops. More than 50 researches were done by the researchers of Hull York Medical School and the University of Hull between 2014 and 2020 to evaluate the level of microplastics in the fish and shellfish globally has proved the claim “If you eat mussels, you eat microplastics”. Among the seafoods, Mussels, oysters and scallops are consumed as a whole including the intestine. Researchers have found that the microplastics are found in the gastrointestinal tract and flesh of few species especially the bivalves and crustaceans have the highest levels of microplastic contamination. The research on consumption shows that the largest consumers of molluscs are China, Australia, Canada, Japan and the United States. Secondly, the largest consumers of molluscs are Europe and the United Kingdom.

The University of Bayreuth team has evaluated the microplastic on four mussel species around 12 countries in the world. The four species of mussels namely European blue mussel, the greenshell mussel, the undulate venus, and the Pacific venus clam which were often sold at food in supermarkets and grocery stores in these countries. The researchers have taken a few samples of farmed mussels, some were collected from the wild catch and few from the off coast of the North Sea, Mediterranean Sea, Atlantic Ocean, South Pacific Ocean, South China Sea, and Gulf of Thailand. 

An unbelievable truth is that all the samples contain microplastics and nine different types of microplastic particles detected at these species. The microparticles were in the size between three to 5000 micrometres. Of the nine different types of microplastics the most common types of plastics detected were Polypropylene (PP) and polyethylene terephthalate (PET).

Question on Human Health effects 

The contamination of microplastics and their growing effects on the aquatic animals has been evidenced. But the question is that, what are the health effects of humans due to these microplastic contaminated food intake. Scientists around the globe are working on the health effects of humans consuming the fish and crustaceans that are contaminated by microplastics. But no one has yet understood the clear health implications caused due to microplastic contaminated seafoods. However early studies have suggested that these microplastics contaminated seafood consumption can do harm furthermore studies are required on addressing the emerging risk.


Despite the emerging human health risk associated with the consumption of the microplastic contaminated seafood. If you eat mussels you eat microplastics is already known to a limited extent. But it varies from oceans to oceans therefore furthermore studies are required on different parts of the world between different Oceans and waterways to understand how these microplastic contamination varies around the globe.  The recent studies by the European researchers have suggested that are microplastic particles are present in the mussels, oysters and scallops in different parts such as gastrointestinal tract, liver etc but more studies are required in identifying what levels of microplastic particles contaminants are ingested by humans through sea food consumption. The current studies have provided that there is a clear need to address the emerging risk and to implement strategies to mitigate the contamination and to protect the environment and marine species from contamination.