Human beings swallow 50,000 microparticles of plastic per year. More, if you like bottled water.

And, The Guardian adds, we also inhale about that much plastic into our lungs as well. The study, published in Environmental Science and Technology, is the first hard look at how much microplastic pollution directly affects us humans:

The new research … took the data from 26 previous studies that measure the amounts of microplastic particles in fish, shellfish, sugar, salt, beer and water, as well as in the air in cities.

The scientists then used US government dietary guidelines to calculate how many particles people would eat in a year. Adults eat about 50,000 microplastic particles a year and children about 40,000, they estimated.

Most food and drink types have not been tested, however, meaning the study only assessed 15% of calorie intake. “We don’t know a huge amount. There are some major data gaps that need to get filled,” said Kieran Cox, at the University of Victoria in Canada, who led the research.

Other foods, such as bread, processed products, meat, dairy and vegetables, may well contain just as much plastic, he said. “It is really highly likely there is going to be large amounts of plastic particles in these. You could be heading into the hundreds of thousands.”

Some of the best available data is on water, with bottled water containing 22 times more microplastic than tap water on average. A person who only drank bottled water would consume 130,000 particles per year from that source alone, the researchers said, compared with 4,000 from tap water.

Scientists do not know what happens when microplastics are inhaled, but the new study speculates that “most inhaled particles will be ingested” rather than coughed or sneezed out. The researchers also estimated that microplastic particles settling on to a single meal per day could add a further tens of thousands to the annual amount consumed.

If you want to read more, the original study is here.