Microplastics: tiny plastic particles in food, water and air, and what science can and cannot say yet

Tiny flecks of plastic now turn up almost everywhere scientists look: in seafood and salt, in bottled and tap water, in indoor air and even in human samples. It is natural to feel uneasy about that, and the honest answer is that nobody yet knows whether the amounts people take in affect health. Food and health agencies in the US and at the World Health Organization say current evidence does not show a risk at the levels found, while also saying much more research is needed. For now, the clearest benefits come from cutting plastic pollution at its source, which is what bans on plastic microbeads and new limits on added microplastics aim to do.

Everyday exposure: where you meet it and how much

Microplastics are very small pieces of plastic, typically considered less than five millimetres in at least one dimension; nanoplastics are even smaller, typically less than one micrometre. There are no standard definitions for either size. [1] Most plastics do not biodegrade; they weather over time into these small particles, and some microplastics are made that size, such as the resin pellets used to produce plastics. [1]

Studies have reported microplastics in foods including salt, seafood, sugar, beer, bottled water, honey, milk and tea. [1] Health Canada says microplastics are found in food, drinking water and indoor and outdoor air; indoors they come partly from fibres shed by clothing, furniture and carpets, and outdoors partly from tire wear. [4] People may be exposed through food, drinking water and air, and FDA adds absorption through the skin from personal care products. [1,4] FDA says there is not sufficient evidence that particles from plastic food packaging migrate into foods and drinks. [1]

Known and suspected harms

Evidence labels are editorial summaries, not individual risk predictions: established means recognized under the stated conditions; probable means a likely contribution with uncertainty; possible means limited evidence; disputed means assessors disagree. These labels do not describe how common an effect is.

• Established — found in food, water, air and human samples: microplastics and nanoplastics have been found in human urine, stool, blood and organs, but not enough is known about their potential health effects. [1]
• Established — no demonstrated risk at levels found in food or drinking water: FDA says current evidence does not show that the levels detected in foods pose a risk to human health. [1] WHO said in 2019 that, based on limited information, microplastics in drinking water do not appear to pose a health risk at current levels. [2,3]
• Possible — effects from very small particles: WHO's analysis found that microplastics larger than 150 micrometres are not likely to be absorbed and uptake of smaller particles is expected to be limited, but absorption of very small particles, including nanoplastics, may be higher; the data are extremely limited. [2]
• Key uncertainty — how to measure them: FDA notes there are no standardized methods to detect, count or characterize microplastics, so many studies have used methods of variable or limited accuracy. [1] Health Canada also says more research is needed on exposure and hazards. [4]

Reducing avoidable exposure and harm

The sources reviewed do not recommend specific steps for individuals to reduce microplastic intake. [1,2,4] WHO's advice to water suppliers is to prioritize removing germs and chemicals known to harm health; treatment that does this also removes microplastics, and wastewater treatment can remove more than 90% of them. [2] WHO also calls for reducing plastic pollution to benefit the environment and reduce human exposure. [2]

What it is

Microplastics are not one chemical but particles that vary in size, shape, colour and polymer type, and they may carry additives used in manufacturing, such as flame retardants or fillers. [1] This variety makes identifying them and assessing their effects difficult. [1]

What it does and why it is used

Most microplastics are unwanted fragments of larger plastics. [1] Some, such as plastic microbeads in toiletries, are added to products on purpose; Canada and the EU restrict these. [5,6]

Regulatory status and health context

Canada

Canada's Microbeads in Toiletries Regulations ban the manufacture, import and sale of toiletries, such as hair, skin and teeth cleansing and exfoliating products, that contain plastic microbeads; the sale ban applied from July 1, 2018, or July 1, 2019, for products that are also natural health products or non-prescription drugs. [5]

United States

FDA says microplastics in food do not violate its rules unless they create a health concern, and it will act if evidence shows harm. It is monitoring research and working on testing methods. [1]

European Union

A REACH restriction adopted in 2023 limits microplastics deliberately added to products, as part of an EU aim to reduce microplastic releases from all sources. [6]

Environmental notes

Limited amounts of plastic are recycled or incinerated, so most plastic waste accumulates in landfills and the environment, where it is found from land and streams to coasts and the ocean. [1] The EU also targets accidental releases, such as losses of plastic pellets. [6]

Quick facts

• Size: typically under five millimetres; nanoplastics under one micrometre. [1]
• Found in: food, drinking water, indoor and outdoor air. [1,4]
• Health risk at current levels: not demonstrated by FDA or WHO; more research needed. [1,2]
• Canada: plastic microbeads banned in toiletries. [5]

Sources

All URLs were fetched on 2026-11-11. Source publication dates differ from this draft's review date.

1. US FDA: Microplastics and nanoplastics in foods.
2. World Health Organization: WHO calls for more research into microplastics and a crackdown on plastic pollution (August 22, 2019).
3. World Health Organization: Microplastics in drinking-water (2019).
4. Health Canada: Plastic pollution, chemicals at a glance.
5. Justice Laws: Microbeads in Toiletries Regulations (SOR/2017-111).
6. European Commission: Microplastics.