In the small study of participants from Europe, Russia and Japan, all eight were found to have microplastic particles in their stool samples. Out of 10 varieties tested for, nine different plastics were identified in the human waste, with polypropylene and polyethylene terephthalate the most common.

Based on their findings, the study researchers expect that tiny bits of plastics may be widespread in the human digestive system.

“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 Philipp Schwabl, the study’s lead and a researcher at the Medical University of Vienna.