According to recent estimations, the amount of plastic microparticles floating in the ocean is 5.25 thousand million, more than the stars in the Milky Way. They weigh a total of 250,000 tons.
This is a significant environmental challenge. According to the United Nations’ International Atomic Energy Agency (IAEA), the polluting elements dissolved in sea water could become attached to these plastic fragments, and marine organisms could ingest them
What are microplastics, and why are they dangerous?
Microplastics are produced by the erosion and disintegration of bigger plastics, such as granules for plastic manufacture or additives used in cleaning, personal hygiene products and synthetic clothes. According to a 2016 IAEA report on the scientific aspects of marine environmental protection, one single synthetic piece of clothing can release approximately 1,900 microfibers during its washing and rising process.
Microplastics and synthetic microfibers are very present in the ocean. As they are designed to be especially resistant, they take a long time to disintegrate and can stay in the environment for over 100 years. They float on the ocean, beaches and seabed. Marine animals often mistake them for plancton and eat them.
Since they are so small, microplastics can be introduced inside internal organs, where they could transfer polluting elements such as polychlorinated biphenyls (PCBs) and traces of metal such as mercury and lead. Pollutants accumulated inside organisms can become part of the food chain and reach humans that consume fish, mollusks or seafood.
Microplastics and polluting agents dissolved in sea water are a threat to marine life
Research with nuclear techniques
New research from the Marine Environmental Studies Laboratory at the IAEA offer hope for a better understanding of the effects of microplastics on marine life.
Researchers are developing methods through nuclear and isotopic techniques to accurately quantify the movement, paths and impact of plastic particles and their associated organic and inorganic pollutants (including fish and shellfish) under laboratory-controlled conditions. With the use of radioisotopes such as carbon-14, they study the way pollutants like PCBs adhere to the microplastics in the environment and whether they can detach from the plastics digested by marine animals.
Research probes into whether particles enter cellular membranes. This transference could take place, for instance, from a female shark to her offspring through the shell in the egg, or through a small shrimp eaten by a fish, potentially reaching its digestive system or possibly its brain or other organs.
Research is also underway to study if plastic pollution affects the way a fish absorbs nutrients. Using radioisotopes, they study the movement and trajectory of microplastics inside animals in order to understand exactly how they are absorbed, through the digestive system or gills, and whether animals can eliminate microplastics or on the other hand they end up clogging their organs. With microplastics accumulated inside their intestine, animals would feel mistakenly full, which would affect their consumption of nutrients.
Nuclear techniques help understand how microplastics and pollutants can enter cellular membranes
Improvements in food safety
Controlled research experiments in aquariums can offer quantitative data and a unique window into the biological impact of microplastics. The collected information improves our understanding of the effect of these plastics on marine organisms significant to society and commerce. This way, it can help countries strengthen their fish and seafood safety and protection programs.
In the words of David Osborn, director of the IAEA Environmental Laboratory, “understanding to what extent microplastics can transfer hazardous contaminants to marine biota is an issue of global concern, in particular for countries that rely on fisheries as a source of food and income”.