West African Coastal Runoff Identified as Primary Source of South Atlantic Oceanic Microlitter

UAB study finds equatorial currents carry West African microlitter to Brazil, with treated cotton fibers making up 90% of large marine debris.

By: AXL Media

Published: Apr 30, 2026, 8:37 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Transboundary Migration of African Coastal Pollutants

Oceanic researchers have successfully traced the geographic origins of the vast quantities of microlitter currently circulating through the South Atlantic, identifying the West African coast as a critical contributor. According to a study conducted by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona, these microparticles are not stationary but are subject to large scale distribution driven by specific marine currents. This movement creates high concentrations of debris near the equator and off the coast of Brazil, effectively turning regional coastal waste into a widespread international environmental challenge.

Mapping Eight Thousand Kilometers of Marine Contamination

The findings are the result of a comprehensive seawater sampling mission that spanned a transect from Salvador, Brazil, to the Strait of Gibraltar. By combining physical samples with advanced oceanic dispersion models, scientists were able to visualize how the velocity and direction of marine currents dictate the fate of approximately 11 million tonnes of plastic that enter the sea annually. Lead author Stéphanie Birnstiel noted that the data proves these particles can accumulate in even the most isolated areas of the Atlantic, traveling immense distances far from their original terrestrial sources.

Equatorial Currents as a Conveyor Belt for Synthetic Waste

The research identifies the equatorial current system as the primary mechanical driver transporting microlitter from West Africa toward South American waters. While the primary flow moves westward, the study also detected secondary inputs flowing from northern Brazil back toward northwest Africa and from the Iberian Peninsula toward the Canary Islands. This complex web of interconnected pathways ensures that human made particles, ranging from rubber and tar to glass and metal, are continuously redistributed across both the North and South Atlantic Oceans.