A study looking at the long-term health effects of tiny plastic particles has found they are not blocked in pregnant rats’ placenta. They were found to pass rapidly from pregnant rats into the heart, brain, lungs, liver and kidney of their foetuses. The in utero rats that were exposed to the microplastics also put on significantly less weight towards the end of gestation. It’s notable because it’s the first study looking at a live mammal that shows the placenta does not block plastic particles. And with microplastic pollution reaching every part of the planet, there’s growing concern about the health impacts on people and animals, with a lot remaining in the ‘unknown’ pile.