The majority of the garbage that enters the ocean each year is plastic—and here to stay. That’s because unlike other trash, the single-use grocery bags, water bottles, drinking straws, and yogurt containers, among eight million metric tons of the plastic items we toss (instead of recycle), won’t biodegrade. Instead, they can persist in the environment for a millennium, polluting our beaches, entangling marine life, and getting ingested by fish and seabirds.
Where does all this debris originate? While some is dumped directly into the seas, an estimated 80 percent of marine litter makes its way there gradually from land-based sources―including those far inland―via storm drains, sewers, and other routes. (An excellent reason why we should all reduce plastic pollution, no matter where we live.) Oil from boats, airplanes, cars, trucks, and even lawn mowers is also swimming in ocean waters. Chemical discharges from factories, raw sewage overflow from water treatment systems, and stormwater and agricultural runoff add other forms of marine-poisoning pollutants to the toxic brew.