As plastic waste proliferates around the world, an essential question remains unanswered: What harm, if any, does it cause to human health?
A few years ago, as microplastics began turning up in the guts of fish and shellfish, the concern was focused on the safety of seafood. Shellfish were a particular worry, because in their case, unlike fish, we eat the entire animal—stomach, microplastics and all. In 2017, Belgian scientists announced that seafood lovers could consume up to 11,000 plastic particles a year by eating mussels, a favorite dish in that country.
By then, however, scientists already understood that plastics continuously fragment in the environment, shredding over time into fibers even smaller than a strand of human hair —particles so small they easily become airborne. A team at the U.K.’s University of Plymouth decided to compare the threat from eating contaminated wild mussels in Scotland to that of breathing air in a typical home. Their conclusion: People will take in more plastic during a mussels dinner by inhaling or ingesting tiny, invisible plastic fibers floating in the air around them, fibers shed by their own clothes, carpets, and upholstery, than they will by eating the mussels.