Image:

This photo captures a view over Plymouth Sound in the UK during Storm Eunice, which struck in February 2022. This location was central to recent research evaluating two years of data on combined sewer overflows into the Sound, compared with weather and satellite information.

Credit: University of Plymouth

A new study indicates that a combination of sewage discharge and coastal wind patterns may be carrying vast amounts of airborne microplastics into nearby coastal cities and towns.

Researchers reviewed two years of sewer overflow data in the Plymouth Sound area, alongside meteorological and satellite observations, to measure how frequently atmospheric conditions were conducive to aerosolisation—when waterborne particles lift into the air.

In their analysis, the team identified 178 days during which sewage discharges to the sea were accompanied by winds reaching speeds of at least 6.5 meters per second (23.4 km/h), blowing back toward Plymouth. These conditions may have facilitated the movement of microplastics and nanoplastics—commonly found in sewage—into the air. According to the data, such events could have persisted for about 1,600 hours, making up approximately 10% of the total study period.

These airborne particles could have been inhaled by residents, raising concerns due to a growing body of research showing the potential health risks associated with breathing in microplastics.

Using satellite imagery, the scientists also identified river plumes resulting from sewage overflows that extended as far as 10 kilometers offshore. There was also a noticeable decline in coastal water clarity during late autumn and early winter—periods associated with a higher number of sewage discharges.

The research, published in the journal Scientific Reports, was performed by specialists in marine science, health, and data analysis from the University of Plymouth and Plymouth Marine Laboratory.

This study builds on previous findings that highlight the presence of microplastics in sewer overflow and the ability of winds to carry sea spray and foam—along with any embedded particles—into the atmosphere over coastal areas.

With many urban areas across the UK and globally still using combined sewer systems, which collect both domestic wastewater and storm runoff, researchers believe this type of pollution—when paired with the right wind conditions—presents a credible and often missed source of airborne microplastic exposure.

Dr. Lauren Biermann, Marine Science Lecturer at the University of Plymouth and lead author of the study, commented: “I’ve seen separate research pointing to high levels of microplastics in sewage overflows, studies showing winds lifting particles off the sea surface, and growing evidence of their health impacts. Our research links water pollution directly with air quality, raising questions about potential health consequences.”

Following these findings, the team recommends more in-depth research to explore how sewage contamination could influence air quality and affect human health.

They also propose integrating monitoring of both air and coastal water conditions in future investigations to better pinpoint avenues of exposure.

Dr. David Moffat, AI and data science expert at Plymouth Marine Laboratory and co-author of the research, added: “There's always been a mismatch between the amount of microplastics we expected in our oceans and what’s actually been recorded. This study helps explain that gap, and the potential consequences for public health are troubling.”

Professor Clive Sabel, Big Data and Spatial Science Professor at the University of Plymouth and research co-author, further noted: “The health stakes are significant. Inhaled microplastics may pass into the bloodstream and accumulate in organs, including the brain and liver. Updated regulations are needed to compel UK water companies to extract microplastics from wastewater.”

Journal

Scientific Reports

DOI

10.1038/s41598-025-06115-5

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

The theoretical role of the wind in aerosolising microplastics and nanoplastics from coastal combined sewer overflows

Article Publication Date

2-Jul-2025