Published in Scientific Reports, the research examined the theoretical conditions necessary for aerosolisation of microplastics and nanoplastics (MNPs). The team looked at records over a two-year period for Plymouth Sound, combining data from sewage overflows with same-day and long-term meteorological and satellite data.
They found that on 178 days across the two years, sewage spills coincided with winds of at least 6.5m/s, which was deemed the threshold for MNP aerosolisation. Specifically, the conditions for blowing these MNPs back onshore towards the city of Plymouth were found to have occurred for almost 1,600 hours, or around 10 per cent of the period studied.
“Our study is the first to make the connection between water pollution and air quality, and raises the question about potential health risks,” said lead author Dr Lauren Biermann, lecturer in Marine Science at Plymouth University.
“Increasingly, I have been reading separate studies about incredibly high concentrations of microplastics and nanoplastics in sewage spills, how winds are stripping microplastics and nanoplastics from the ocean surface into the air, and the negative impacts of ingested or inhaled microplastics and nanoplastics on human health.”
With thousands of cities around the world still using combined sewer systems – where treated sewage merges with storm runoff – the study suggests coastal spills and aerosolising winds may well be causing onshore airborne MNPs. Though the findings in the study are theoretical, the Plymouth team is calling for further investigation into links between sewage spills and air quality, as well as the potential risks to human health.
“The health implications of this work are important. Inhaled microplastics can cross into our blood streams and from there can accumulate in organs such as our brains and livers,” said study co-author Clive Sabel, Professor of Big Data and Spatial Science at the Plymouth University.
“We need legislation to force our UK water supply companies to remove microplastics from our waste water systems.”
The study, ‘The theoretical role of the wind in aerosolising microplastics and nanoplastics from coastal combined sewer overflows’, was conducted by experts in marine science, human health and big data from Plymouth University and Plymouth Marine Laboratory.
