Unless you’re very ill, it’s not likely anyone will be analyzing your poop under a microscope anytime soon. But if someone did, you might be surprised that among the assorted bacteria and waste lurks something a little more disconcerting: traces of plastic.

The disturbing revelation that humans are internalizing plastic material was announced this week at the United European Gastroenterology conference in Vienna. Researchers at the Medical University of Vienna found plastic in stool samples from eight donors, each from a different country (Poland, Russia, Japan, the Netherlands, the UK, Austria, Finland, and Italy). The poop donors volunteered their excrement for the sake of science, shipping their deposits in biohazard packaging for lab evaluation under the direction of the Environment Agency Austria. All submitted samples tested positive for a variety of plastics, from polyethylene (found in storage containers) to polypropylene (bottle caps) to PVC.

For each quarter-pound of the samples, 20 particles of microplastics were discovered ranging in size from 50 to 500 microns. A 50-micron particle is the smallest visible to the human eye.

Naturally, this means we have to be ingesting plastic in order to be excreting it. Scientists aren’t yet sure of the exact sources, though the food logs submitted by subjects might provide some clues. They drank from plastic bottles, ate from plastic containers, and ate fish that may have been exposed to plastic waste in polluted water.

The discovery is likely to encourage more wide-ranging studies involving a greater number of individuals about the possible health effects of having plastic particles in our digestive systems or bloodstreams. It may also be a call to reduce our dependence on plastics in general, and for food-related purposes specifically. In the meantime, gratitude is due the researchers and microscopists who went through a lot of crap to retrieve this data.

[h/t WIRED]