Together with The Ocean Cleanup HKV Consultants has made a first estimation of the plastic input from rivers into oceans. The results of this research have been published in Nature Communications. Our study suggests that the global riverine system is contributing between 1.15 and 2.41 million metric tons per year of plastic waste into the world’s ocean. We found that two thirds of this input were generated by the top 20 most polluting rivers and that these were mostly located on the Asian continent. The estimation is based on open source geospatial information on population density, waste management, topography, hydrography and locations of dams worldwide.
We formulated an empirical equation based on these indicators and calibrated our model against field measurement data reported in scientific literature. As we successfully reproduced observations for various rivers across the world, we used our calibrated model to draw a global picture of yearly inputs of plastic from rivers into oceans. Understanding the spatial and temporal variability of plastic in rivers is key to understand the global marine plastic pollution issue. Our data and framework are publicly available to assist the community in prioritizing monitoring and in designing mitigation policies.