(CN) – The average American consumes more than 70,000 pieces of microplastics per year, though the health effects of that consumption are unclear.
Microplastics are tiny, often microscopic, pieces of plastic. We come in contact with microplastics through multiple sources, including the degradation of larger plastic products in the environment or the shedding of particles from food and water containers. Humans can inadvertently take in the materials when eating food or breathing air containing microplastics.
Researchers from the University of Victoria, the Hakai Institute, and Fisheries and Oceans Canada reviewed 26 previous studies that analyzed the amounts of microplastic particles in fish, shellfish, added sugars, salts, alcohol, tap or bottled water and air. Using these studies, the team estimated that they were considering roughly 15% of Americans’ caloric intake.
The team then assessed approximately how much of these foods are consumed using the recommended dietary intakes of the 2015-2020 Dietary Guidelines for Americans. From this analysis, the estimated microplastic consumption ranged from 74,000 to 121,000 particles per year, depending on age and sex. People who drink only bottled water could consume an additional 90,000 microplastics annually compared with those who drink only tap water.
Of the sources available for study, air, bottled water, and seafood accounted for the large majority of microplastic intake. Salts, tap water, and alcohol seemed to present the lowest microplastic consumption risk, though the researchers note this may be because people consume considerably less of those items as a percentage of their total caloric intake.
Other than inhaled particles, the greatest concentration of microplastics by volume seems to be in bottled water, which contained more than 20 times as many microplastic particles as tap water.
Given the limited scope of sources that had data on microplastic content available, the researchers warn these values are likely underestimates.
The health effects of ingesting microplastic particles are unknown, but some pieces are small enough to enter human tissues where they could trigger immune reactions or release toxic substances. The research team stresses additional research is needed to understand the health effects, if any, of the ingested particles.
They published their research in the ACS journal Environmental Science & Technology on Wednesday.