Microplastics have been found in human stool for the first time, according to a new study presented in Vienna Tuesday, shedding some light on the pervasiveness of the pollutant.
The study’s authors estimate that “more than 50% of the world population might have microplastics in their stools,” the Guardian reports, but more research is needed to support this.
According to the National Ocean and Atmospheric Administration, microplastics are small plastic pieces less than five millimeters long, often broken off from larger, disintegrating pieces of plastic pollution. Microbeads, tiny pieces of polyethylene plastic used in some beauty products as exfoliants, are another source of the harmful particles.
Both the United States and the European Union banned the use of microbeads in the last couple years, but the amount of plastic pollutants in the environment—particularly in the oceans—is already monumental.
Due to their small size, microplastics are easily consumed by sea creatures, entering the food chain. This study, conducted by researchers from the Medical University of Vienna and the Environment Agency Austria, determined that these particles eventually reach humans, although it’s not certain where exactly the microplastics originate.
The researchers analyzed the stool of eight participants from countries around the world, including Finland, Italy, Japan, the Netherlands, Poland, Russia, the U.K., and Austria. Each participant kept a food log throughout the study, showing they were exposed to plastics through bottled water or plastic-wrapped food. None of the participants were vegetarians, and six of them ate seafood.
Every single stool sample tested positive for microplastics, the study reports. Researchers looked for 10 different types of plastics. Up to nine were found, sized between 50 and 500 micrometers, with polypropylene (PP) and polyethylene terephthalate (PET) being the most common. On average, the researchers found 20 particles of microplastic for every 10g of stool.
“This is the first study of its kind and confirms what we have long suspected, that plastics ultimately reach the human gut. Of particular concern is what this means to us, and especially patients with gastrointestinal diseases,” said lead researcher Dr. Philipp Schwabl, at the United European Gastroenterology week in Vienna, where he presented the study.
“While the highest plastic concentrations in animal studies have been found in the gut, the smallest microplastic particles are capable of entering the blood stream, lymphatic system and may even reach the liver,” he continued. “Now that we have first evidence for microplastics inside humans, we need further research to understand what this means for human health.”