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Which types of plastic items make up much of the debris found in rivers, oceans, and shorelines?

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Ubiquitous plastics — plastic pollution A volunteer collecting plastic nurdles (pellets less than 0.2 inch [0.5 centimeter] in diameter) at Barreiras Beach, Corrubedo, Spain.

A significant portion of the plastic debris found in rivers, oceans, and along shorelines consists of single-use items. Specifically, a 2021 study determined that 44 percent of plastic pollution in these environments is composed of bags, bottles, and items associated with takeout meals.1

Beyond these larger objects, a substantial fraction of aquatic plastic waste is made up of microplastics—fragments less than 5 mm (0.2 inch) in length. These particles originate from two primary sources:12

Secondary microplastics: Formed when larger plastic items, such as packaging and bottles, break down due to weathering from sunlight, wave action, and wind abrasion.34
Primary microplastics: Tiny plastic pieces that enter the environment directly, including microbeads used in personal care products and synthetic fibers shed from clothing during laundering.32

Because these plastics are not biodegradable, they persist in the environment, accumulating in ecosystems and posing serious risks to wildlife through ingestion and entanglement. Addressing this crisis is a moral imperative, as the continued accumulation of these materials threatens the health of global aquatic life and the integrity of our natural world.1324