A new paper presented on 22 October at the United European Gastroenterology Conference in Vienna has reported the initial findings of a pilot study with a small sample size, which found that stool samples of all of eight participants of the study ― from Finland, Italy, Japan, the Netherlands, Poland, Russia, the United Kingdom, and Austria ― were positive for a variety of microplastics. This is the first study of its kind to document these materials in humans but the findings only lead to further questions like where did these microplastics come from and what are the risks to human health.
Microplastics are tiny plastic particles less than 5 mm in size and have been found in other species such as birds, fish, and whales, so it seems inevitable they would make their way into the digestive system of humans. However, so far very little is know about the effects this could potentially have on human health. Microplastics could cause an immune response in the gut or if small enough, these tiny fibres could make their way into the bloodstream, lymphatic system, liver, or other organs where they could cause problems. The variety of polymers identified in the study suggests a wide range of contamination sources, which could include food packaging, clothing, and other plastic products. In addition, microplastics are known to be present in the food chain ― in particular, studies have shown high levels of microplastics in fish (1).
Every year, eight million tonnes of plastic waste finds its way into the world’s oceans. Microplastics are mostly the result of larger plastics breaking down. Sunlight and wave action break down waterborne plastics and fibres from synthetic clothing made from plastics like polyester and acrylic can make their way into freshwater systems through washing machines. As a consequence, tiny pieces of plastic are scattered all over the planet. Once in the sea, microplastics are consumed by marine species and enter the food chain. It is also highly likely that food processing and plastic packaging further contaminate our food with plastics.
Each participant of the study maintained a food diary during the week leading up to stool sampling, showing that all of them consumed plastic wrapped foods or drank from plastic bottles, and six consumed fish from the sea. The stool samples were analysed by the Environment Agency Austria and out of the ten types of plastic tested for, nine different plastics were found, ranging in size from 50 to 500 micrometres. Polypropylene (PP) and polyethylene terephthalate (PET) were most common and an average of 20 particles per 10g of stool was detected. The full publication is not yet available yet but should be completed by November.
Larger studies are still needed to confirm the results. Lead researcher Dr Philipp Schwabl, a gastroenterologist at the Medical University of Vienna, hopes these findings will drive more research into the effects of microplastics on human health and he states, “Now that we have first evidence for microplastics inside humans, we need further research to understand what this means for human health.”
(1) Wieczorek, A.M. et al. Frequency of Microplastics in Mesopelagic Fishes from the Northwest Atlantic. Frontiers in Marine Science (2018) DOI: 10.3389/fmars.2018.00039