People in the United States could be taking in more than 100,000 plastic particles a year in food, drink and air.

The average US resident consumes tens of thousands of tiny plastic particles each year, according to a detailed estimate.

Minute, often microscopic, plastic particles called microplastics can enter food, water and the air from sources such as plastic packaging. Kieran Cox and his colleagues at the University of Victoria in Canada analysed data from 26 published studies to determine the levels of microplastics in air and commonly consumed items such as water — bottled and tap — alcohol and seafood. The authors then estimated the total number of microplastics a person consumes and inhales.

The team found that people in the United States take in 74,000–121,000 particles annually, depending on age and sex. People who drink only bottled water might swallow 90,000 particles with their water each year, compared with just 4,000 for those who stick to tap water. Microplastics data are unavailable for many foods, including beef, poultry, dairy, grains and vegetables, meaning that the researchers’ numbers are probably underestimates.

More research is needed to understand the health implications of ingesting microplastics, the authors say.