What microplastics and nanoplastics are
The FDA describes microplastics as very small pieces of plastic, typically less than 5 millimeters in at least one dimension. Nanoplastics are even smaller. The U.S. Environmental Protection Agency (EPA) defines microplastics as particles from 5 millimeters, about the size of a pencil eraser, down to 1 nanometer, and nanoplastics as the subset smaller than 1 micrometer. Nanoplastics can't be seen with the naked eye.
They come from two main places:
- Made small on purpose. EPA calls these primary microplastics, such as particles manufactured for some consumer products. The FDA gives resin pellets used in plastic production as an example.
- Broken down from larger plastic. Most plastics don't biodegrade. The FDA explains that they break down over time from weathering in the environment into smaller and smaller particles. EPA notes they can keep breaking down into nanoplastics.
Where microplastics show up
EPA says microplastics have been found in every ecosystem on the planet, from the Antarctic tundra to tropical coral reefs, and in food, beverages, and human and animal tissue.
According to the FDA:
- studies have reported microplastics in foods including salt, seafood, sugar, beer, bottled water, honey, milk and tea
- they reach food mainly through environmental contamination where foods are grown or raised
- there isn't sufficient scientific evidence to show that microplastics and nanoplastics from plastic food packaging migrate into foods and beverages
- people may also be exposed through the air and through the skin from personal care products
- microplastics and nanoplastics have been found in human samples, including urine, stool, blood and organs
What the FDA says about health risk
The FDA's position, as of its page last updated July 24, 2024, has three parts:
- No demonstrated risk at current levels. Current scientific evidence does not demonstrate that the levels of microplastics or nanoplastics detected in foods pose a risk to human health.
- Presence alone isn't a violation. Environmentally derived microplastics in food don't violate FDA regulations unless they create a health concern.
- More research is needed. Some studies suggest there may be health impacts, but the FDA says not enough is known about potential effects and that it needs more research before it can assess them.
The FDA also explains why the science is hard. There are no standardized methods to detect, count or characterize microplastics, so studies are difficult to compare. Plastics vary widely in type, density and the chemicals added during manufacturing, which affects how they break down and makes toxicity hard to assess. Fewer studies exist on nanoplastics because measurement methods are less developed.
The agency says it continues to monitor the research, and that if it determines, based on scientific evidence, that microplastics in food are harmful, it can take regulatory action.
What about tap water and bottled water?
Tap water. The FDA notes that EPA sets limits for contaminants in drinking (tap) water but that there are currently no regulatory levels for microplastics or nanoplastics in drinking water. EPA's research program says there's a pressing need to develop and standardize methods to collect, extract, measure and identify micro- and nanoplastics.
Bottled water. The FDA says several studies have found microplastics in both tap and bottled water, and that the evidence doesn't currently show that those levels pose a risk to human health. The FDA regulates bottled water and generally adopts EPA's tap-water standards for it, or finds that a standard isn't necessary for bottled water.
What WHO found. In a 2019 review of microplastics in drinking water, WHO said that, based on limited information, microplastics in drinking water don't appear to pose a health risk at current levels, and called for more research and for reducing plastic pollution. WHO also reported that:
- microplastics larger than 150 micrometers are not likely to be absorbed by the body, and uptake of smaller particles is expected to be limited
- wastewater treatment can remove more than 90% of microplastics from wastewater, with the most removal from advanced treatment such as filtration
- water treatment that removes germs and harmful chemicals is also effective at removing microplastics, so WHO advises water suppliers to keep focusing on known risks first
In 2022, WHO followed up with a broader report on exposure through food, water and air, reviewing data published through December 2021 and laying out research needs to address current uncertainties.
What the FDA checks on food packaging
The FDA says there are no regulations that authorize microplastics or nanoplastics as ingredients added to food. For plastic used in food packaging, processing equipment, food preparation surfaces and cookware, the law requires materials that touch food to be authorized by the FDA before they're marketed for that use. As part of that review, the FDA looks at data on how much of a substance can migrate into food under its intended conditions of use.
That last point is practical: a container's safety review is tied to how it's meant to be used. Following the label, for example using only containers marked for the microwave or dishwasher in those appliances, keeps you within those conditions.
What you can reasonably do
The agencies don't recommend specific steps for avoiding microplastics, and there's no evidence that any one step lowers health risk. These are sensible, low-cost moves that follow from what they do say:
- Know your tap water. Your water system's annual quality report lists regulated contaminants. Our guide to reading your water report explains it. Microplastics won't be listed, because there's no federal limit.
- Don't switch to bottled water just for microplastics. The FDA says both tap and bottled water have been found to contain them.
- Use plastic food containers as labeled. FDA safety reviews are based on intended use, so follow the microwave, dishwasher and reuse directions.
- Test for what's regulated. If you're worried about your water, start with contaminants that have known health effects. See how to choose a water test, and if you're comparing filters, use our water filter checklist to check what a filter is certified to remove.
- Cut plastic waste where it's easy. WHO calls for reducing plastic pollution to benefit the environment and reduce human exposure.
Use cases: what to do in common situations
- "I saw a headline that bottled water is full of nanoplastics." Studies have found them, but the FDA says current evidence doesn't show the levels pose a health risk. Bottled water isn't a cleaner swap for tap water on this point.
- "Should I stop eating seafood or sea salt?" The FDA lists both among foods where microplastics have been reported, but says current evidence doesn't show a risk at the levels found. Make food choices based on overall nutrition.
- "I microwave leftovers in plastic tubs." Use containers labeled microwave-safe for that purpose, since the FDA reviews food-contact materials for their intended use.
- "My water report doesn't mention microplastics." That's expected. There is no federal limit, so utilities don't report them.
Frequently asked questions
Are microplastics in food harmful?
The FDA says current scientific evidence does not demonstrate that the levels of microplastics or nanoplastics detected in foods pose a risk to human health. It also says not enough is known about potential health effects and more research is needed.
Which foods contain microplastics?
The FDA says studies have reported microplastics in salt, seafood, sugar, beer, bottled water, honey, milk and tea, among other foods. They mainly enter food through the environment where it's grown or raised.
Is bottled water safer than tap water for microplastics?
Not according to the evidence so far. The FDA says studies have found microplastics in both tap and bottled water, and that the levels haven't been shown to pose a health risk in either.
Is there a legal limit for microplastics in drinking water?
No. EPA sets limits for many drinking-water contaminants, but the FDA notes there are currently no regulatory levels for microplastics or nanoplastics in drinking water.
Do microplastics leach from food packaging?
The FDA says there isn't sufficient scientific evidence to show that microplastics and nanoplastics from plastic food packaging migrate into foods and beverages. Packaging materials must be FDA-authorized for their intended use.
What has WHO said about microplastics?
In 2019, WHO said microplastics in drinking water don't appear to pose a health risk at current levels, based on limited information, and called for more research and less plastic pollution. Its 2022 report on food, water and air exposure set out further research needs.
This guide is general information, not medical advice. Talk with your clinician about your own situation.