Americans consume more than 70,000 microplastic particles every year from the food they eat, the water they drink, and the air they breathe, according to a new study published in the journal Environmental Science & Technology. Scientists warn that while the health impacts of ingesting these tiny particles are largely unknown, there is potential for the plastic to enter human tissues and cause an immune response, as well as release toxic chemicals into the body.

The analysis, done by biologists at the University of Victoria in Canada, examined data from 26 previous studies on microplastic contamination in seafood, sugars, salts, honey, alcohol, tap water, bottled water, and in urban air. It found that Americans eat and drink an estimated 39,000 to 52,000 microplastic particles every year, depending on age and sex. Those numbers jumped to 74,000 to 121,000 when scientists included inhalation of microplastics.

Americans who drank water solely from plastic bottles consumed an additional 90,000 particles annually, compared to 4,000 particles for people who drank only tap water.

The scientists warn that their findings are “likely drastic underestimates overall.” Just 15 percent of a person’s caloric intake is associated with the consumption of up to 52,000 microplastics annually. And the researchers note that several major U.S. food groups — including poultry, beef, dairy, grains, and vegetables — have not been studied for their microplastic contamination. In addition, the scientists’ weren’t able to assess how much plastic might be entering our bodies from food packaging.

The study’s findings “suggest that microplastics will continue to be found in the majority, if not all, items intended for human consumption,” the scientists wrote. “If the precautionary principle were to be followed, the most effective way to reduce human consumption of microplastics will likely be to reduce the production and use of plastics.”