Plastic litter and other waste on a sandy beach, with an umbrella in the background.

What Are Microplastics? Sources, Environmental Concerns and Health Evidence

Microplastics are small plastic particles, usually described as less than five millimetres in size. They can form as larger plastics break down or be manufactured at a small size. Nanoplastics are smaller still; definitions and measurement methods differ between scientific and regulatory contexts.

The important distinction is between finding plastic particles, understanding their effects in a particular setting, and establishing the risk from an actual level of exposure. Those are related questions, but they are not interchangeable.

Where do microplastics come from?

The European Commission identifies sources including wear from tyres, fibres from synthetic textiles, industrial pellet losses and the breakdown of larger plastic litter. Some particles are also intentionally added to products.

A plastic item becoming brittle and fragmenting is not the same as it harmlessly disappearing. Plastic pollution can persist and spread through water, soil and air. The issue therefore extends beyond the waste visible on a beach.

Why are they an environmental concern?

Small particles are difficult to recover after they disperse. EFSA describes their persistence and their occurrence in marine, freshwater and terrestrial ecosystems, including food chains. Studies have reported physical and toxic effects in organisms under particular experimental conditions.

That does not mean that every plastic particle causes the same effect at any concentration. Size, composition, exposure and the organism being studied matter. A laboratory result should not be presented as a direct measurement of what happens to every person or animal outdoors.

What do we know about human health?

EFSA’s information reviewed on 21 October 2026 says that knowledge of dietary exposure and potential health effects remains limited. Its full risk assessment of microplastics and nanoplastics in food has not yet been completed. It cannot currently draw a conclusion on potential health effects from that assessment.

The FDA also states that current evidence does not demonstrate that the levels detected in foods pose a human-health risk. This statement concerns the evidence available for food exposure; it is not a declaration that all particles, doses and exposure routes are harmless.

Finding particles in food or a biological sample does not, by itself, establish that they caused a disease. Equally, an incomplete evidence base is not proof of no risk. Avoid both alarmist promises and categorical reassurance.

Practical choices without “plastic-free” promises

Our editorial suggestion is to focus on identifiable waste problems: prevent avoidable litter, secure small items before a windy trip and take damaged equipment home for suitable repair or disposal. These actions address waste management; we are not claiming a measured reduction in your personal microplastic exposure.

Care for clothing according to its instructions. Do not replace an entire usable wardrobe merely because an article mentions synthetic fibres. This guide has not tested laundry filters, capture bags or claims that a particular accessory prevents particle release.

Does a reusable bottle solve the problem?

No single purchase resolves microplastic pollution. A reusable bottle may help you avoid some disposable packaging, but that is a different claim from proving that a particular bottle eliminates exposure or improves health. Assess the complete product, including its lid, seals, permitted drinks and care requirements.

For a broader approach to avoiding unnecessary waste, read What Is Zero Waste? and Use What You Own.

Sources and scope

Updated 2 November 2026. An introduction to published evidence, not medical advice or a product test. Scientific assessments may change as evidence develops.

“Illustrative image of plastic litter, not a close-up of microplastic particles.

”Photo: Lucien Wanda / Pexels.

Back to blog