New research uncovers how long viruses can survive in seawater after sewage discharges
A new BlueAdapt study published by Bangor University and the University of Exeter highlights the potential health risks of viruses surviving in coastal waters.
With climate change driving more frequent storms and heatwaves, untreated wastewater carrying human viruses can end up in the ocean, where viruses can persist for longer than previously thought.
Key Findings:
- Viruses can remain a threat in seawater for at least 72 hours, and sometimes over two weeks.
- Traditional testing methods overestimate how quickly viruses decay in the environment.
- Viral persistence decreased with rising temperatures, but heatwaves don’t eliminate the risk entirely.
The study examined seven common viruses found in wastewater, testing how long they survive in seawater at different temperatures. Researchers used two methods to assess this: traditional qPCR, which measures viral RNA, and Capsid Integrity qPCR (CI-qPCR), which focuses on viral viability.
The results revealed an important difference: while qPCR showed viral presence for longer periods, CI-qPCR indicated that many of these viruses were still potentially infectious long after qPCR would suggest they had decayed. This underscores the importance of using advanced methods, like CI-qPCR, to provide improved monitoring to keep people safe, rather than relying on traditional methods alone.
Lead Author, Dr Jessica L. Kevill, says: “The findings show that while higher temperatures can reduce the survival of viruses, they don’t eliminate the risk altogether. So on a nice sunny day, your risk of getting sick from swimming is much lower than on a cloudy day, following a rain storm. But the risk is still there. None of us want to swim in polluted waters which is why this work is so important.”