Austrian scientists have found microplastics in human stool for the first time. The study results suggest the problem may be widespread across our food chain.
Researchers studied stool samples from eight participants across the world, in Finland, Italy, Japan, the Netherlands, Poland, Russia, the UK and Austria. They kept diaries of their food intake for a week before all their stool samples tested positive for at least one form of microplastic.
Microplastics are very small pieces of plastic (under five millimeters in length) that pollute the environment. The pieces found in the stool samples ranged between 50 to 500 micrometers (half a millimeter.)
Researchers compared the participants’ food diaries and found that all eight had been exposed to plastic-wrapped foods, while six had eaten seafood. On average, 750 milliliters of water was drunk from plastic water bottles by the participants.
The stools were tested for 11 kinds of microplastics. Up to nine were identified in each participant. Polypropylene (PP) and polyethylene terephthalate (PET) - major components of plastic bottles and caps - were found in all the samples.
Though the study’s sample size was small, the team behind the research says they’re not sure if the microplastics came from participants’ diets.
"We don't have exact evidence from where this is coming from,” said Alistair Boxall, professor in environmental science at the University of York in England. “It could be that most of these materials may be coming from house dust and the use of plastic containers and packaging or, for example, nylon fibers from our tumble dryer - and this could potentially outweigh the environmental routes of exposure," he noted.
Boxall has called for more work to be done to understand where ingested microplastics originate.