Microplastic contamination of the oceans is one of the world’s most pressing environmental concerns. The terrestrial component of the global microplastic budget is not well understood because sources, stores and fluxes are poorly quantified. We report catchment-wide patterns of microplastic contamination, classified by type, size and density, in channel bed sediments at 40 sites across urban, suburban and rural river catchments in northwest England. Microplastic contamination was pervasive on all river channel beds. We found multiple urban contamination hotspots with a maximum microplastic concentration of approximately 517,000 particles m⁻². After a period of severe flooding in winter 2015/16, all sites were resampled. Microplastic concentrations had fallen at 28 sites and 18 saw a decrease of one order of magnitude. The flooding exported approximately 70% of the microplastic load stored on these river beds (equivalent to 0.85 ± 0.27 tonnes or 43 ± 14 billion particles) and eradicated microbead contamination at 7 sites. We conclude that microplastic contamination is efficiently flushed from river catchments during flooding.

Defra: The Telegraph, BBC News and The Times have today reported on research from the University of Manchester which found the River Tame near Manchester has the highest level of microplastic pollution of any river in the world. We are very clear that plastic pollution is a threat to our natural environment and are working with the Environment Agency and the water industry to reduce the amount that enters our land, rivers and the sea and protect wildlife for future generations. We have already set out in our ambitious 25 Year Environment Plan measures to eliminate avoidable plastic altogether by the end of 2042 so that we leave our environment in a better state than we found it, including plans to extend the 5p plastic bag charge, improve recycling rates and explore plastic free aisles in supermarkets. We have already introduced a world-leading ban on microbeads. Pollutant loads to rivers from the water industry have declined significantly in recent years, and over 70% of rivers now receive ‘good or better’ status in terms of their biological health – up from 56% in 1990. Click here to read more