The Invisible Threat of Microplastics

Plastic waste is a major ecological concern. Global plastics production totaled around 335 million metric tons in 2016, of which roughly half was intended for single-use products. And while it’s common to see discarded soda bottles and plastic bags littering the ground, the invisible threat of microplastics are much harder to identify.

Microplastics are defined as plastic particles smaller than 5mm. Some are created specifically for cosmetics and skin care products, but they can also be formed as larger pieces of plastic break down in the environment. Environmentalists have been warning people for decades that microplastics have the potential to cause severe harm to fish and other wildlife.

But while the effects of microplastics on marine life have been studied for decades, the extent of microplastic pollution on land is just beginning to be explored. So far, the findings aren’t great.

A recent study led by South Korea and Greenpeace and published in the Journal of Environmental Science & Technology found microplastics present in 90 percent of table salts tested worldwide. The study tested salt samples from 21 countries in Europe, North and South America, Asia, and Africa, finding microplastics in 36 of the 39 brands tested. The density of the microplastics found varied dramatically based on brands, with salt sold in Indonesia containing the highest quantities. It’s worth mentioning that Indonesia was ranked as having the second-worst level of plastic pollution in the world in an unrelated 2015 study.

Additional studies have found microplastics in tap water around the world, and one report from Italy even found microplastics in industrial beverages like soft drinks and iced tea.

Because of the widespread microplastic contamination, experts have begun testing for traces of the substance in humans. Researchers from the Medical University of Vienna conducted a small pilot study of eight participants from Finland, Japan, Italy, the Netherlands, Poland, Russia, Austria, and the United Kingdom. Despite the geographic, dietary, and societal differences of the subjects, all eight stool samples tested positive for the presence of microplastics. The authors estimate that more than 50% of the global population may have microplastics in their stools based on their results, stressing the need for a larger-scale study to confirm their findings.

Research detailing the effects of microplastics on humans and other mammals is limited, and still being studied. Studies have shown that birds that ingested plastic have developed tiny, fingerlike nodules inside the small intestine that disrupts iron absorption and adds stress to the liver. One concern is that harmful bacteria could cling to the surface of microplastics and get ingested. Other scientists have suggested that if microplastics are broken down to the nanometer size range they could be absorbed by the circulatory system, killing or injuring cells.

Only time will tell if microplastics have a negative health impact on humans. But considering the amount of plastic waste that is still being produced, the problem isn’t going away any time soon.