Something you have might experienced before on the beach; just as you planted your feet in the sand you start to feel little pieces of plastic between your toes. This is actually a substantial part of marine litter, you can’t see it but you can feel it. A recent scientific study found that every kilogram of European sand contained on average 250 microplastics: fragments smaller than 5 mm. There are even traces of significantly smaller plastic fragments, called nanoplastics. Ironically, these tiny bits of plastic cause the greatest problems. All different types and sizes of plastic form the plastic soup. The world’s ever increasing use of plastics has created large areas of floating plastic waste in rivers and oceans and many of these plastics break down into smaller fragments. Our demand for plastic does not only have devastating consequences for the oceans, but marine wildlife is also affected by plastic pollution. It appears that fish tend to mistake the scent of plastic for food and ingest it on purpose. Because the vast majority of plastics is not biodegradable, let alone (bio)degradable, it will remain in the environment for a long time. Through various ways, for example by eating fish and shellfish, these small fragments of plastic have entered our food chain and our bodies.
Plastic debris in the world's oceans
The world’s seas and oceans are clogged with plastic debris and we’re still adding millions of tons more plastic to marine environments every year. According to the Ellen MacArthur Foundation, our oceans will contain more plastic than fish by 2025. Plastic litter – plastic bags, fishing nets, for example – enters oceans through rivers, wind, weather. The floating pieces are made of plastic (components) like polypropylene (PP), polyethene (PE) and polyethylene terephthalate (PET). In the ocean even the largest bits of plastics are broken up and degraded by the waves. Ultraviolet radiation, from sunlight, makes plastic brittle, and heat and wave action shear it off into flakes. Over time, the flakes are shredded further by the elements, becoming smaller and smaller,ending up as microplastics or nanoplastics. Most of these small plastic particles are, as said, non-biodegradable or/and not soluble in water. It’s no rocket science to understand that this ‘plastic soup’ has become a worldwide problem.
Tiny particles of plastic in our food
Much of the discussion surrounding micro- and nanoplastics in the environment has been focused on the creation of micro- and nanoplastics, but since various new studies show that these tiny plastic fragments also enter our food chain through - e.g. fish and shellfish consumption (shrimp, mussels and such). Next to seafood, scientists also point to other foods, such as milk and honey. These products were accidentally contaminated in the production process. Apparently in some cases the used machinery was cleaned with a substance containing plastic scrub particles.There are also common intentional uses of microplastics, so-called “microbeads”, particularly for personal care products. These too will eventually end up the environment and the food chain. At the same time there is still a lot unclarity about the diffusion of micro- and nanoplastics. The amount of microplastics has been measured in oceans and seas, but there are currently no standardised methods for measuring the occurrence of all these types of plastic particles in foods.
Scientific research on microplastic pollution has until now been mainly focused on the effects on the oceans. Since public concerns about micro- and nano-plastics are mounting due to, above mentioned, their potential risks for human health. Especially now that new studies on microplastics have revealed that these small particles are detected in our food chains. To date, little research has been done into the presence of harmful substances in microplastics and the health effects derived from consumption. The problem with microplastics is however that they are comprised of various different types of plastics. Moreover, the plastic particles are often compounds, and contain (a multitude of) additives (like plasticisers) and thus vary immensely in composition. A recent study from Swedish Örebro University presents a series of new findings from various parts of the world that clearly show that microplastics can damage marine animals, but it remains uncertain if there is a defendable limit of safe exposure of microplastics on animals and humans. Since these small plastic particles are low in weight, they easily come off and find their way into water, foods or body tissue, with potential health hazards. It is therefore expected that in the coming years much more (scientific) research will be conducted into micro- and nanoplastics and their overall impact on human health.