LONDON—Scientists have found tiny pieces of plastic in human stool for the first time, suggesting they may now be embedded in the food chain.
Although the study was small, with just eight participants from Europe, Russia, and Japan, all of their samples were found to contain microplastics.
The results surprised the researchers from the Medical University of Vienna and the Environment Agency Austria, who recorded nine different types of plastic in the samples. The most common were polypropylene and polyethylene terephthalate.
Twenty microplastic particles were found in every 10 grams of stool, indicating that humans are most likely ingesting them through food.
None of the participants in the study were vegetarians and six of them ate fish.
In diaries kept by the participants the week before submitting a sample, researchers found they were all exposed to plastic-wrapped food or drinks in plastic bottles.
The implications for our understanding of gastrointestinal diseases is significant, lead researcher Dr. Philipp Schwabl said, although he stressed larger-scale research is needed.
“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,” Schwabl said in a statement.
“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.”
Impact on Immunity
Scientists still don’t know the effects of microplastics on the human body, but the researchers think they may affect the digestive system’s immunity to disease, or encourage the transmission of toxic chemicals.
“Now that we have first evidence for microplastics inside humans, we need further research to understand what this means for human health,” Schwabl said.
Microplastics are defined as any piece of plastic less than 5 millimeters (0.2 inches) in size; they are produced in various industries but the fragments also can be formed by the weathering of plastic products in the environment.
Scientists have found that microplastics act like a sponge and absorb other chemical pollution already found in the water, such as DDT, a pesticide linked to reproductive system damage that was banned in the United States 40 years ago, but is still used in some countries, such as China.
It’s estimated that 2 percent to 5 percent of all plastics produced end up in the oceans. Once there, the plastic is eaten by sea animals and enter the food chain. Significant amounts of microplastics have been found in tuna, lobster, and shrimp, scientists said.
It’s now virtually impossible to remove these plastics from the food chain, but many governments are seeking to limit plastic use by consumers or the production of microplastics themselves.
Earlier this year, the European Parliament approved an EU-wide ban on microplastics in cosmetics, which followed U.S. legislation signed in 2015 by then-President Barack Obama banning their use in cosmetics. In addition, many U.S. cities are moving to ban plastic straws and single-use items such as cotton swabs and drink stirrers, which can break down into microplastics.
Some microplastics are small enough that they could be inhaled in the air we breathe, according to Frank Kelly, a British environmental health professor.
However, professor Alistair Boxall from the UK’s University of York, said he isn’t worried by the new study.
“Microplastics have been found in tap water, bottled water, fish, and mussel tissue and even in beer,” he told the Independent.
“We will also be exposed to particles from house dust, food packaging materials, and the use of plastic bottles. It’s therefore inevitable that at least some of these things will get into our lungs and digestive systems.”
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