A study by the Austrian Environment Agency and scientists from the University of Vienna has found microplastics in human stools.
Researchers tested stool samples collected from eight participants belonging to different countries. Tests determined that all the samples contained microplastics.
All the participants are exposed to plastic as they consume plastic-wrapped food or drink from plastic bottles, while six of them eat sea fish.
Up to nine varieties of microplastics were found in the samples, with tests indicating that polypropylene and polyethylene terephthalate were the most commonly found plastics.
On average, each 10g of human excreta contained 20 microplastic particles, with sizes ranging between 50µm and 500µm.
The findings have triggered concerns over the possible implications for human health.
Lead researcher Dr Philipp Schwabi said: “Of particular concern is what this means to us, and especially patients with gastrointestinal diseases.
“While the highest plastic concentrations in animal studies have been found in the gut, the smallest microplastic particles are capable of entering the bloodstream, lymphatic system and may even reach the liver.
“Now that we have first evidence for microplastics inside humans, we need further research to understand what this means for human health.”
Microplastics are any form of plastic particles that are less than 5mm. They are barely visible to the naked eye and are used in various products, including synthetic clothing, road paint, and cosmetics.
Researchers expressed concerns that the concentration of plastic particles in the gut could damage the immune system, cause inflammation, and assist in the transmission of toxins.
Plastics ending up in the oceans are consumed by sea creatures and could be eventually ingested by humans.