Plastic pellets are a visible pollutant on beaches. I have not seen any evidence that they're a particularly harmful pollutant. A single 20 tonne containerload of plastic pellets can leave a visible residue on hundreds or thousands of beaches, but the 15 tonnes of CO2 emitted by the average American every year is entirely invisible.
https://static1.squarespace.com/static/5ff6c5336c885a268148b...