Photo: Nguyễn Hiệp/Unsplash
- We now know plastics run in human blood. These include nanoparticles of polyester, used to make objects like food containers.
- Microplastics are tiny pieces of plastic smaller than 5 mm in diameter.
- An international treaty on plastic pollution is on the cards – it could be crucial to microplastic, and plastic, menace.
Kochi: Plastic pollution is one of the most pressing environmental problems of our time. Plastic litter is a common sight in urban areas but it has also found its way into the wild. It is in every natural habitat imaginable: forests, deserts, rivers, soil.
Even our highest mountains and deepest oceans haven’t been spared. Trekkers have left behind plastic waste on Mt. Everest, the world’s tallest peak. In 2019, a submersible dove into the Mariana trench, the world’s deepest point in the ocean, and found a plastic grocery bag and sweets wrappers on the seafloor. We are launching thousands of satellites into space; debris from these spacecraft – including plastic – are drifting around there.
Name any ecosystem you can think of. If humans have been there (or nearby), so has plastic.
Plastic is not just around living things but inside them too. Elephants in South India have been pooping plastic bags and face masks they accidentally ate along with organic waste from dumpsites in the wild.
Now, a new study has found that microscopic fragments of plastic also run in our veins. Scientists from the Netherlands analysed blood samples from 22 people and found four types of microplastics in them. This included particles of polyethylene terephthalate (or polyester, used to make clothing and plastic bottles) and styrene, widely used in many industries including food-packaging.
Every millilitre of blood contained 1.6 micrograms of plastic on average; the highest concentration was at just over 7 micrograms.
As the name suggests, microplastics are microscopic pieces of plastic. Usually, they are fragments smaller than 5 mm wide.
Microplastics arise from both primary and secondary sources. Primary sources are those where plastic has been crafted in tiny pieces – like plastic pellets or tiny beads that are 2-5 mm wide. They are made from polyester (which in turn is made from petroleum and coal). Pellets are a common raw material in the plastic industry because they can be melted down to manufacture many other larger plastic products, like plastic bags and containers. Other primary sources of microplastic include microbeads, which are found in several personal care products including face scrubs, and paint.
Secondary sources of microplastics include plastic bags, bottles and almost every other plastic object that breaks down into smaller pieces over time.
Such pieces are often invisible to the human eye. In the new study, the sizes of microplastics were around 700 nm in diameter. That is around 140 times smaller than the width of a single human hair.
Because microplastics are so small, it is difficult to ascertain the extent to which they have invaded our planet and the bodies of its living things. We can only be sure for now that wherever scientists go looking for microplastics, they will strike gold.
A big deal?
In 2020, scientists found tiny fibres of microplastic in the snow atop Mt. Everest. According to them, these fibres likely came from the clothing, tents and ropes that mountaineers use.
In 2015, scientists estimated that there were 15-51 trillion microplastic particles floating in surface waters worldwide. Microplastics can be extremely damaging to marine and aquatic systems. Microbeads, for example, look a lot like fish eggs and a variety of marine and aquatic creatures can eat them. When we eat these bigger fish, our bodies accumulate more microplastic particles.
Environmentalists, policymakers and governments appear to be taking note of the dangers of microplastics in the environment. At the UN Environment Assembly earlier this month, more than 170 countries pledged to develop an international, legally-binding treaty to tackle plastic pollution by 2024. This draft resolution includes microplastics as a type of pollutant.
While we have found microplastics everywhere, we don’t exactly know how they can harm humans, although some of its components are likely to be bad news. For example, styrene – one of the microplastics that scientists recently discovered in human blood – could be a human carcinogen.
But as we wait for more studies, one thing is certain: we need to act fast. This is why the international treaty on plastic pollution could be crucial. Some curbs on plastic pollution could go a long way to stem the invasion of microplastics.