microbead

:  a tiny sphere of plastic (such as polyethylene or polypropylene) ◆Microbeads are used especially as exfoliants in facial scrubs and body washes and to add texture to other personal care products (such as toothpastes and lip balms). The microscopic plastic microbeads found in many popular soaps and cleansers pose a real threat to both water and soil. These microbeads are not biodegradable. They are so tiny that they are able to pass right through the filters used to treat our wastewater. — Mariyana Spyropoulos, The Chicago Daily Herald, 23 June 2014