Microplastics are plastic pieces smaller than 5mm. While larger plastic waste and its impact can be clearly visible – dirty beaches, entanglement of marine species, injury or suffocation – microplastics and their impact are not always visible to the human eye.
This does not mean that they aren’t there or that the consequences of microplastics in the environment are any less severe. Microplastics likely make up most of our marine pollution (by number of pieces), so there is a higher chance that these tiny pieces of plastic will be eaten by fish and other marine animals, potentially ending up in the human food chain.
What kinds of microplastics are there?
Primary microplastics are manufactured to be small pieces of plastic, not plastic that has broken down to that size. Two commonly found primary microplastics are plastic pellets and plastic microbeads. Plastic pellets are the raw form of plastic before the plastic is turned in bottles, toothbrushes or any other plastic item. Plastic microbeads were commonly used in personal care products to act as an abrasive scrubbing agent to cleanse skin, but are more often now being replaced by natural ingredients, either voluntarily or due to government legislation. Primary microplastics, like all plastics, degrade to smaller sizes over time.
Plastic pellets found on a beach in Hong Kong
Plastic microbeads extracted from a face scrub
Secondary microplastics are caused by the wear and tear of plastic items once they are in use. Microfragments come from larger or whole plastic items. This can be from hard plastics (such as bottles, containers, etc.) or soft plastics (such as wrappers, bags, etc.) and from polystyrene such as take-away boxes or fishing floats. They can also be produced by wear and tear from tyres and from washing clothing made from synthetic materials.
This fragmentation of whole plastic items into smaller pieces can be caused by sun exposure, general wear and tear and mechanical processes.
A brittle plastic container fragmenting due to photodegradation
Shredded plastic from a processing plant washed up on a beach
What problems do microplastics pose?
They’re everywhere, and they will be everywhere for a long time!
According to research 93% of bottled water and 83% of tap water worldwide contains microplastics. Microplastics are also present in the air we breathe and the food we eat! Microplastics have been found in arctic ice samples, in Antarctica and also on the top of mountains.
Microplastics can adsorb (bond with) chemicals that are in the surrounding water. Chemicals can accumulate on microplastics in higher concentrations than in the surrounding seawater. These chemicals are often known as Persistent Organic Pollutants (POPs). POPs are toxic chemicals that adversely affect human health and the environment. The chemicals remain in the environment for long periods of time and can accumulate and pass from one species to the next through the food chain.
How much microplastic is in the ocean?
The global release of microplastics (from synthetic clothing, tyres, city dust, road markings, marine coatings, personal care products and plastic pellets) in the oceans was estimated to be
1.5 million tons/year
The largest proportion of the microplastic particles stem from laundering of synthetic textiles and from the abrasion of tyres while driving.
Primary microplastics in the oceans IUCN 2017
Microbeads are less than 1mm in size and are used in personal care products, household cleaners, and by industry and manufacturers as an abrasive agent.
Pellets are pre-production plastic resin beads used to make plastic products. They can be from virgin sources or from recycled plastic.
Microfibres are tiny strands of plastic released from nylon ropes or fishing nets and synthetic clothing.
Car tyres shed rubber particles into the environment. Recycled car tyres are crumbed and used as infill for sports pitches and for playgrounds.
Did You Know?
Toxic chemicals in the sea water such as PCBs, Dioxin and flame retardants known as Persistant Organic Pollutants (POPs) bond readily with microplastic making them highly toxic plastic pieces.
Did You Know?
Ingested microplastic is known to induce an inflammatory response in the tissues of the fish or marine life, especially if the plastic is small enough to pass through the gut wall.
Did You Know?
Microplastics bioaccumulate up the food chain. As small fish are eaten by larger fish, any plastic that has been ingested could remian in the guts of the fish.
Resources & Reports
SOURCES, FATE AND EFFECTS OF MICROPLASTICS IN THE MARINE ENVIRONMENT: A GLOBAL ASSESSMENT (GESAMP (2016)