How much should we worry about the health effects of microplastics?

It seems every few months, we discover microplastics in a new part of the body. We have found them in our livers, kidneys, lungs and guts. They have even shown up in human breast milk and blood. Last week, they turned up again in eight people’s olfactory bulbs, a brain structure crucial for smell.

These plastic fragments are so small – less than 5 millimetres in size – they can make their way into our bodies through food, water and even the air…