The world's sea floor is littered with an estimated 14 million tonnes of microplastics , according to Australia's national science agency CSIRO.
Microplastics are tiny plastic particles with an upper size limit of 5mm in diameter. The term ‘microplastics’ was introduced in the mid-2000s. They occur in the environment as a consequence of plastic pollution.
Every year, several million tonnes of plastic litter course through rivers and out to the oceans, where they are gradually broken down into smaller fragments through the motion of waves and the ultraviolet light of the sun.
Marine organisms such as fish, crabs and prawns consume these microplastics by misidentification as food. Humans consume this seafood which leads to several health complications.
Microplastics are divided into two categories:
Primary microplastics which enter the environment directly, are tiny particles designed for commercial use, as well as microfibers shed from clothing and other textiles, such as fishing nets.
Examples of primary microplastics include microbeads found in personal care products, plastic pellets used in industrial manufacturing, and plastic fibres used in synthetic textiles.
Secondary microplastics form from the breakdown of larger plastics such as water bottles.
This typically happens when larger plastics undergo weathering, through exposure to conditions like wave action, wind abrasion, and ultraviolet radiation from sunlight.
Microplastics contribute to over 80% of the ocean debris . In the last four decades, concentrations of these particles appear to have increased significantly in the surface waters of the ocean, according to the UN Environment Programme.
Although a global problem, only 43% of the countries are actively involved in studies on microplastics.
About half the global population lives within 100 km of a coastline, and population growth is greatest in that zone. This means the amount of plastic debris entering the ocean from land-based sources is likely to increase unless significant changes are made to waste management practices on land.
As the world population grows and more products containing microplastics are placed on the market, the amounts of primary microplastics entering the marine and coastal environment is likely to increase.