Microplastic are small plastic pieces less than five millimetres long which are harmful to life in the oceans and to our health. Microplastic come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces.
Micro-Plastics sifted out of the sand at Ghajn Tuffieha Bay, Malta
The occurrence of small plastic particles on beaches and in coastal waters was first reported in the 1970s although the term ‘microplastic’ was not used until recently. It is now evident that the distribution of plastic debris of all sizes is global, including uninhabited islands in the open ocean and at the Arctic and Antarctic. It is estimated that up to 75 per cent of the micro-plastics found in the ocean are from the breakdown of larger material.
Micro-plastic particles arise as a result of four separate processes:
- deterioration of larger plastic items, cordage and films (bottles, plastic bags, fishing gear, etc.) over time, with or without assistance from UV radiation, mechanical forces in the seas (e.g. wave action, grinding against shorelines), or through biological activity (e.g. boring, shredding and grinding by marine organisms);
- direct release of micro particles (e.g. scrubs and abrasives in household and personal care products, shot-blasting ship hulls and industrial cleaning products respectively, grinding or milling waste) into waterways and via urban wastewater treatment;
- accidental loss of industrial raw materials (e.g. prefabricated plastics in the form of pellets or powders used to make plastic articles), during transport or trans- shipment, at sea or into surface waterways;
- discharge of macerated wastes, e.g, sewage sludge.
Microbeads are a type of microplastic. They are very tiny pieces of manufactured polyethylene plastic that are added as exfoliants to health and beauty products, such as some cleansers and toothpastes (take a look at your scrubs or toothpaste at home – if they list polyethylene in the ingredients, those are microplastics). These tiny particles easily pass through water filtration systems and end up in the ocean and are harmful to marine life.
Microbeads are used in cosmetic products, toothpaste and exfoliants
Micro-beads are not a recent problem. According to the United Nations Environment Programme, plastic micro-beads first appeared in personal care products about fifty years ago, with plastics increasingly replacing natural ingredients. As recently as 2012, this issue was still relatively unknown, with an abundance of products containing plastic microbeads on the market.
It is likely that the amount of plastic waste in the ocean will continue to increase, driven primarily by the inexorable rise in plastics consumption (circa 9% per annum), and the continued inadequacy of re-use, recycling and waste management practices in many parts of the world.
Fishing gear and large plastic items washed up by the sea at Ghajn Tuffieha Bay, Malta
Interactions of large plastic items with animals such as seabirds, marine mammals and turtles through entanglement or ingestion are well known, killing millions annually. We are just now becoming aware of the harmful, albeit so far non-lethal, impacts on the health of individuals and the human population.
Even less is known about the potential impacts of microplastics on a wide range of smaller organisms, at the bottom of the food chain, exposed to various particle sizes and the chemical constituents of plastic.
Weathering and disintegration lead to a slow decrease in the size of the particles. This increases the likelihood that a wider range of animals, which are further down in the food chain such as marine plankton, will ingest the particles. It also increases the surface area of the particles, which means that there is more opportunity for the particles to either absorb chemicals or to release them, through a process called chemical exchange.
A selection of plastic items washed up by the sea at Ghajn Tuffieha Bay, Malta
Different plastics have different characteristics and among those differences is density. Some plastics float and some sink, and this has an impact on where the microplastic particles end up in the environment, although very little is known about their ultimate fate, for instance if they eventually sink to the seafloor.
There is evidence that these particles can act as vectors of contaminants and carry these harmful substances from the water column and into the organisms that consume them, such as fish.
A major contributor to microplastic fibres pollution is synthetic clothing made from nylons and polyester. Some clothing manufacturers are funding research into the rates of shedding of their clothing and evaluating new manufacturing methods that can reduce these losses. It may be a case of too little, too late.
Studies have demonstrated that microplastic particles are also airborne and settle in large quantities in urban settings.
Plastic is a manufactured product—it does not occur naturally, so anywhere we find it in nature is directly because of us. It represents the waste product of our current lifestyle, which is heavily reliant on plastic products.
People can have a positive impact on plastic pollution through their lifestyle choices. You should avoid purchasing products with excess packaging; choose glass or metal drink containers over plastic; avoid disposable plastic bags and take reusable bags with you; choose wool or cotton instead of synthetic garments. Lastly, to help with the plastic that you don’t purchase sign up to participate in a coastal clean-up near you.
Click on this link to see more articles on plastic pollution.
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