How Do Microplastics Form

How Do Microplastics Form? Learn the Three Main Causes

The invention of plastic has drastically changed the way we package products, eat, dress and live but this has come at a cost to the environment.

One of the consequences of plastics is the creation of microplastics. While tiny in size, these small bits of plastic can have a gigantic impact on the ecosystem. 

What are Microplastics?

Microplastics are tiny pieces of plastic that are five millimetres or less in diameter. These small particles are released from both household and industrial products. Microplastics exist in different forms, including fibres, fragments, pellets, spheres and films. 

Some microplastics are intentionally designed to be this small. These include the tiny plastic beads used in cosmetic products like facial scrubs and toothpaste.

Other microplastics originate from the breakdown of of larger plastic objects during production and use.  

Why are Microplastics Bad for the Environment?

Plastic pollution in our forests, rivers and oceans impacts the planet’s biodiversity by harming animals and damaging fragile ecosystems that we depend on for climate regulation, oxygen and food.

The tiny size of microplastics makes it easy for them to be spread quickly, carried by wind and water. 

Microplastics that make their way to the ocean can combine with harmful chemicals and be eaten by marine organisms.

The effects of microplastics on aquatic animals depend on the chemical composition of the plastic but are thought to include reduced feeding behaviour and fertility, impaired development and structural damage to organs.

When microplastics enter the environment, they are not just harmful to animals, but also potentially to our health as it enters our food and water supplies.

We are exposed to microplastics via ingestion of food and water, breathing and skin contact, meaning we are constantly accumulating microplastics in our bodies. Microplastics have even been found in breast milk.

How Do Larger Plastic Items Break Down?

Improperly managed plastic waste that ends up littered on land or in the ocean becomes weathered and breaks into smaller pieces.

Larger plastic items break down into secondary microplastics due to exposure to environmental forces such as solar radiation, wind and water. 

Read more: Why is the Ocean Important? 

How Do Microplastics Form? Here Are Three Ways 


Some microplastics are made as microplastics. One prime example is microbeads, which are  used as exfoliants in personal care products and the abrasives in toothpastes.

Canada banned the manufacture and import of all toiletries that contain plastic microbeads in 2018, but they are still legal in several countries, including Japan and Germany.   


Some microplastics form through the breakdown of large pieces of plastic such as bottles and packaging materials. When plastic items are disposed of, they may be exposed to mechanical stress and environmental forces, like temperature fluctuations, sunlight and wind, that cause them to break into smaller pieces.

Microplastics can also form due to abrasion during use, as is the case with tires while driving or the soles of footwear while walking.

Fibre Shedding 

Microfibres are a type of microplastic that is shed from synthetic textiles during manufacture, wearing and washing.

Clothing made from synthetic materials like nylon, acrylic and polyester release microfibres into the water when you wash them and this wastewater ends up in sewers and eventually oceans.

Microplastics can also form due to abrasion during use, as is the case with tires while driving or the soles of footwear while walking.

FAQs About How Do Microplastics Form?

Where Do Microplastics Come From?

Primary microplastics are intentionally manufactured for use in commercial products, while secondary microplastics are created by the breakdown of larger plastics.

The seven major sources of microplastics are synthetic textiles, plastic pellets, tires, road markings, marine coatings, personal care products and city dust. 

How Do Humans Generate Microplastics?

Humans rely heavily on plastic materials in nearly every aspect of our lives. From packaged food and transportation to the clothing we wear and the cosmetic products we use, plastic has infiltrated everything.

Humans generate microplastics simply by failing to dispose of plastics properly, which contributes to littering and plastic pollution in the ocean that breaks down into microplastics.

What Creates the Most Microplastics?

Most microplastic pollution is thought to come from synthetic textiles, making it all the more important to support sustainable fashion.

Though it may not be obvious, nylon, acrylic, polyester and other synthetic fibres are types of plastics.

Each time these clothing items are washed, they shed microfibres that drain through into wastewater and enter our rivers, groundwater and oceans. Another major source of microplastics is the abrasion of vehicle tires while driving. 

Final Thoughts on How Microplastics Form

Microplastics are ubiquitous, having been detected in our oceans, soil, air, food, drinking water and our bodies.

Once they are in the environment, they are nearly impossible to remove. The health impacts of microplastics are still being investigated, but it’s highly unlikely they are doing any good to the environment or human health.

In the meantime, it’s important to understand how microplastics form so we can minimize this form of pollution to the best of our ability.

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