“Microplastics” are pieces of plastic that are less than 5mm long. Microplastics can either come from larger pieces of plastic that have broken down over and over again, or they can be manufactured. For example, the little plastic beads ("microbeads") in face wash are considered microplastics. “Microfibers” are also a type of microplastic. They include small fibers that enter the water from washing clothing made of synthetic materials, like polyester or nylon. See our page on plastics to learn more.