You Probably Ingest Thousands of Microscopic Pieces of Plastic Each Year

Scientists who studied human feces believe people inadvertently consume thousands of microscopic plastic particles each year. Austrian researchers studied the stool samples of eight people from around the world, and found miniscule pieces of the substance in every one.

More than 350 million tons of plastic is created annually, some of which finds its way into the environment. These include tiny microplastic particles measuring less than 5 millimeters, which are either created at that size or are worn down from larger pieces, according to the authors of the study published in the journal Annals of Internal Medicine.

The research involved eight adults living in Japan, Russia, Netherlands, U.K., Italy, Poland, Finland, and Austria who each gave scientists a stool sample. The participants also documented their diet six to seven days before collecting the sample, and let the researchers know the ingredients of the toothpaste, chewing gum and cosmetic products they used.

Scientists at Austria for Medical University of Vienna and the Environment Agency Austria looked for ten common plastics in the feces. There was an average of 20 microplastic particles per 10 grams of human stool. The average adult human stool weighs approximately 100 grams.

Most of the food the participants ate was presented or stored in plastic. Seven consumed drinks from plastic bottles every day, six ate seafood, while three used cosmetic products like shower gel, face wash, or hand cream containing synthetic polymers. None of the toothpastes or chewing gums contain microplastics, according to the packaging.

Polyethylene and polyethylene terephthalate were the most common plastics the researchers found. The former is the most common plastic in the world, and used to make products such as shopping bags; while the latter is used in items such as permanent-press fabrics, photographic film, and plastic bottles.

The team wrote that the findings suggest people ingest these plastics from a range of sources including food product processing, preparation, and packaging, as well as in water and the air. However, the plastics studied were not present in the personal care products.

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A stock image of a child drinking from a plastic bottle. Researchers have investigated whether we inadvertently consume plastic. Getty

Existing studies suggest the average person takes in 13,731 to 68,415 microplastic particles from the air per year; 4,400 to 5,800 from tap water; 123 to 11,000 from shellfish; and 37 to 1,000 from salt.

However, the researchers acknowledged their study is limited by the small sample size, and research involving more people is needed to make the findings relatable to a wider population.

"Research on the origins of microplastics ingested by humans, potential intestinal absorption, and effects on human health is urgently needed," they concluded.

In the wake of the explosion of plastic production in the past century, scientists are working to understand the impact this has on the environment and our health. Past research cited by the team has found plastic in seafood, sea salt, and drinking water.

One study published in the journal Nature Geoscience earlier this year found pieces of plastic can travel up to 100 kilometers, or 62 miles, through the air, according to scientists who studied pollution in a remote area in the mountains of France.

And a separate team of scientists looking for microplastics in the digestive systems of sea animals stranded off the U.K. coast discovered the material in every creature they tested. Their findings were published research in the journal Scientific Reports.