An unprecedented amount of microplastics are floating around in our oceans, and more and more of it is making its way into the animals that call oceans their home. Scientists even recently discovered microplastics in ice from Antarctica, suggesting that even the Earth's most remote regions are not immune to their spread.
This ever-evolving spread of microplastics is slowly starting to gain more attention, with various research groups from around the world trying to figure out what, if any, health risk microplastics found in food and water pose to humans and other animals.
Microplastics spreading in the oceans are of particular interest due to the widespread consumption of seafood around the globe. Various fish species, shrimp, and other shellfish like mussels have been found to be riddled with microplastics. Now, researchers at the University of Bayreuth have made another important conclusion to add to the previous discoveries of microplastics in mussels.
The research, published in the journal Environmental Pollution, found that microplastics are present in at least four of the most commonly sold mussel species from seafood markets around the globe. This suggests that it is very likely for anyone eating mussels to be consuming microplastic particles as well.
The researchers discovered a total of nine different types of microplastics in the four sampled mussel species: the European blue mussel, the Pacific venus clam, the undulate venus, and the greenshell mussel. These mussels were all bought in grocery stores and were farmed from different oceans around the world. The two most commonly found microplastics in the mussels were polypropylene and polyethylene terephthalate, both plastics that are very commonly used by people, linking it to human activity.
Due to the natural difference in the size of each of the mussel species, the researchers used 1 gram (0.035 ounces) of mussel meat as a comparable reference point for all four species to compare the amounts of microplastics found in each specimen. On average, they found 0.13 and 2.45 microplastic particles in 1 gram (0.035 ounces) of mussel meat in the four different species analyzed.
Furthermore, the size of the microplastic particles they discovered ranged anything between 0.003 and 5 millimeters (0.0001 to 0.2 inches). The researchers used a special purification technique to help distinguish between different particles. "To analyze the types of microplastic, we used so-called random forest algorithms for the first time in this study, both for the immensely large micro-FTIR data sets and for the Raman measurement data. These enabled us to evaluate data quickly, automatically, and reliably," said Dr Martin Löder, one of the authors of the study, in a statement.
The current study did not assess the health risks involved from ingesting microplastics while eating these mussels, and very little is currently known about the health risks of eating or drinking microplastics for humans and animals. However, it has been found that various human organs even contain microplastics, including the placenta, illustrating that it is not only aquatic life forms that are at risk of been riddled with microplastic particles and that more needs to be done to understand the potential risk to life.
"Our new study represents an important advance in terms of methodology. We have combined the latest technologies and procedures in sample preparation, measurement, and analysis of microplastic contamination in such a way that comparable results can be obtained on this basis in the future. Such methodological harmonization is an indispensable prerequisite for correctly assessing and evaluating risks potentially emanating from the spread of microplastics in the environment," concluded Professor Dr Christian Laforsch, the corresponding author of the study.