A new American study has found microplastics in brain tissue, at levels up to 30 times higher than in other tissues in the body. This comes after years of disparate research, which has found microplastics in other parts of the human body, like the heart and the placenta.

Today, science reporter Angus Dalton on whether this is, as one toxicologist has put it,  a “global emergency”. And whether microplastics might have been acting, for decades, as the “dark matter” driving all sorts of health issues, like dementia and plunging male fertility.