Supplementary data for 'River plastic emissions to the world's oceans'

Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.

Modelled plastic inputs into the ocean from rivers worldwide.

The shapefile contains 40,760 river input locations (EPSG:4326, WGS 84) with the following attributes:

i_level: plastic input in tonnes per year. (level=low, mid or high for lower, midpoint and upper estimates)

i_level_month: plastic input in tonnes per month. (level=low,mid,high; month=jan,feb,...,dec)

runoff_month: monthly averaged runoff in catchment in mm per day. (month=jan,feb,...,dec)

mpw: mismanaged plastic waste production in catchment in kg per year.

area: catchment area in square meters.