About 8 million metric tons of plastic waste winds up in the oceans every year—bottles, bags and doo-dads that eventually break down into tiny pieces, called microplastics. These inedible bits have now been found in human fecal samples, but do microplastics cause harm to people? That’s the question many researchers are pondering, according to an article in Chemical & Engineering News (C&EN), the weekly newsmagazine of the American Chemical Society.