Jennet Orayeva, IAEA Department of Nuclear Sciences and Applications 3 minutes
According to the UN Environment Programme, 8 million tonnes of plastic end up the world’s oceans every year, often carried there by rivers. If the trend continues, by 2050 our oceans could contain more plastic than fish.
Environmental plastic pollution has become a major ecological and societal concern. Plastic pollutants vary widely in size, from large debris, such as fishing nets and single-use plastic bags, to invisible nano-sized plastic particles. While the visible impact of large plastic debris, so-called macroplastics, in marine environments has been well documented, the potential harm caused by microplastics and even more by nanoplastics is much less clear.
Plastic particles below 5 mm in length are called microplastics. The smaller ones, with a size equal to or less than 100 nm (1/10 000 mm) are called nanoplastics. They are so tiny that one cannot see them with naked eye or even with an ordinary optical microscope.
Microplastic particles are accidentally consumed by marine organisms, which are then consumed by predator fish. Nanoplastic particles are even more toxic to living organisms as they are more likely to be absorbed through the walls of digestive tracts and thereby transported into the tissues and organs. Consequently, such plastic particles can interfere with various physiological processes, from neurotransmission to oxidative stress and immunity levels of freshwater and marine organisms.
Over the last decade, the global scientific community has invested substantial work into advancing the knowledge of the impact of plastic debris on diverse aquatic organisms. However, monitoring methods for small microplastics and nanoplastics are still in the development phase, which means that their exact concentration in the oceans remains unknown.
“This is where nuclear technology can play an important role,” added Metian. “Nuclear and isotopic techniques are already successfully used to study pollution processes. Their advantage is that they are highly sensitive and precise and can be used similarly to study small microplastic and nanoplastic movement and impact.”
At the same time, from a toxicology perspective, it is important to distinguish the toxicity of plastic particles per se from the toxicity associated with the contaminants that can become attached to them. To date, research into the effects of virgin micro and nano-sized plastic particles in freshwater and marine fish is still limited, hence the increased focus on investigating the toxicity of virgin plastics at the IAEA.