Extremely small bits of plastic are everywhere, and the Chesapeake Bay is no exception. The so-called microplastics, often 5 millimeters or less in size, can be scooped from the surface waters of the Patapsco River and combed from the Bay’s underwater grass beds.

Microplastics that originated as tiny beads in some face scrubs, soaps and toothpastes are now banned by federal law.

But most microplastics begin in much larger pieces: chunks of litter and debris — water bottles, car tires and even plastic piers — that break down into increasingly smaller pieces but don’t biodegrade for hundreds of years. Those plastic bits can leach chemicals or become a carrier of toxins and invasive species they pick up as they float through the water.

Scientists now know that single-celled organisms in the aquatic environment can easily mistake the smallest particles of plastics for food. Those bits then travel up the food chain, eaten by larger and larger fish that are eventually eaten by humans.