Damian Carrington in The Guardian:
The average person eats at least 50,000 particles of microplastic a year and breathes in a similar quantity, according to the first study to estimate human ingestion of plastic pollution. The true number is likely to be many times higher, as only a small number of foods and drinks have been analysed for plastic contamination. The scientists reported that drinking a lot of bottled water drastically increased the particles consumed. The health impacts of ingesting microplastic are unknown, but they could release toxic substances. Some pieces are small enough to penetrate human tissues, where they could trigger immune reactions.
Microplastic pollution is mostly created by the disintegration of plastic litter and appears to be ubiquitous across the planet. Researchers find microplastics everywhere they look; in the air, soil, rivers and the deepest oceans around the world. They have been detected in tap and bottled water, seafood and beer. They were also found in human stool samples for the first time in October, confirming that people ingest the particles. The new research, published in the journal Environmental Science and Technology, 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.