How does plastic pollution reach oceans from land?

Plastic pollution reaches the ocean from land primarily because the ocean acts as the downstream receiving body for terrestrial waste. Because most synthetic plastics are nonbiodegradable, improperly discarded items persist in the environment and are transported through several pathways:123

• Diffuse Sources: Much of the debris originates from litter that is carried by wind, stormwater runoff, and rivers that transport waste from both urban and rural areas into aquatic systems.12
• Intentional and Improper Disposal: Plastic waste is often dumped illegally, discarded at the site of use, or overflows from inadequate containment structures and landfills.132
• Industrial and Infrastructure Inputs: Plastic enters the environment through wastewater outfalls, industrial facility discharges, and unintentional spills during manufacturing or transport.12
• Microplastic Pathways: Primary microplastics, such as fibers from synthetic textiles or microbeads from personal care products, enter the environment directly through wastewater treatment systems.2

Preventing this pollution requires improved waste management and a fundamental commitment to stopping plastics from entering the environment at the source.1