New tool exposes source of pollutants in rivers and lakes

By Imogen Howse via SWNS

A new water quality analysis tool can identify what is causing pollution in rivers and lakes.

Scientists have discovered a way to distinguish whether water is polluted by pesticides, microplastics, aerosols, or other chemicals – and can also establish what impact these things are having on a particular freshwater source.

They say this will help them crack down on the main culprits of pollution and better protect bodies of water across the world.

A team from the University of Cambridge in the UK and Trent University in Canada developed a tool that can pinpoint the origin of specific organic matter dissolved in a body of water.

Dissolved organic matter influences a range of processes in rivers and lakes, including carbon storage, nutrient cycling, and food web interactions – that together determine ecosystem function.

“The thousands of different dissolved organic compounds can keep freshwater ecosystems healthy, or contribute to their decline, depending on the mixture present,” researcher Jérémy Fonvielle explained.

The new tool therefore uses high-resolution mass spectrometry to analyze water and provide a comprehensive overview of all molecules present – also revealing whether the combination is having a positive or negative effect

“Microparticles from car tires, pesticides from farmers’ fields, and toxins from harmful algal blooms are just some of the chemicals that can be detected using the new approach,” said Mr Fonvielle.

“This makes it possible to monitor the health of freshwater through the diversity of molecules and compounds present.”

During the study, which has today been published in the journal Science, the researchers reviewed various rivers and lakes across Europe and Canada.

Analysis of Lake Erie in Canada revealed high levels of phosphorus pollution – and, by looking at the composition of individual molecules in the water sample, the team discovered that agricultural activities were the source of this pollution.

Discussing the significance of this revelation, researcher Dr. Andrew Tanentzap said: “Before, we could measure the amount of phosphorus pollution in a river, but we couldn't really identify where pollution was coming from.

“However, with our new approach, we can use the unique molecular fingerprint of different sources of pollution in freshwater to identify their source.”

He also highlighted the speed of the new tool, which will help teams act fast when a river or lake is in trouble.

“More traditional approaches to monitoring water quality involve taking lots of different measurements with many devices, which takes a lot of time.

“Our technique is a very simple way to get a comprehensive overview of what’s going on in a particular river or lake, and can be done within an hour.”