A nationwide citizen science project has found high levels of chemical pollutants in freshwater bodies across the UK.

Thousands of volunteers have helped to provide a snapshot of the health of the nation’s rivers and waterways, highlighting high levels of nitrates and phosphates, as well as a cocktail of chemical compounds that pose a risk to ecosystems.

The WaterBlitz project, led by charity Earthwatch, is an annual water quality survey that recruits members of the public and community groups twice a year to take thousands of water samples from freshwater bodies in England, Wales, Scotland and Northern Ireland.

Rivers are the still the lifeline of the UK, and that none pass good overall health status represents a national failure. More needs to be done to urgently clean up our water. Dr Leon Barron School of Public Health

As part of this year’s September WaterBlitz, researchers from Imperial’s School of Public Health distributed hundreds of additional kits to help detect a range of chemical pollutants.

The findings of the Imperial-led analysis found traces of pharmaceuticals such as antibiotics and painkillers, agricultural chemicals, pesticides, and stimulants including caffeine and nicotine.

Dr Leon Barron, Reader in Analytical and Environmental Sciences in the School of public Health at Imperial College London, said: “We’re delighted to be a partner in this year’s Water Blitz.

"Community science projects are increasingly important in monitoring chemical pollution in our environment. It’s thanks the help of hundreds of people across the UK who put their local knowledge to good use to collect samples and to enable such detailed snapshots of the health of our nation’s rivers.

“Our analysis has already identified several chemicals at levels which exceed accepted safe limits for aquatic life. We found pharmaceuticals, pesticides and even common substances like caffeine and nicotine at detectable levels in water up and down the country.

“What this work highlights is that despite treatment facilities being in place, these chemicals continuously find their way into our waterways. Rivers are the still the lifeline of the UK, and that none pass good overall health status represents a national failure. More needs to be done to urgently clean up our water.”

Comprehensive analysis

Dr Barron and team, which includes research assistants Juditha Gurumurthy and Margarita White, analysed samples from the Waterblitz in the Environmental Research Group’s labs at Imperial’s White City Deep Tech Campus.

In total, 91 water samples were comprehensively analysed. The findings revealed levels of antidepressants (venlafaxine), antibiotics (trimethoprim), and painkillers (tramadol and diclofenac) in significant proportions of samples, likely coming from urban wastewater sources.

Agricultural contaminants were found in several samples, including fungicides (tebuconazole) and pesticides (acetamiprid), indicating agricultural runoff as a source of pollution. Analysis also revealed the presence of stimulants caffeine and nicotine. Many of the substances are recognised as potentially harmful to wildlife.

The full WaterBlitz report, published today (Wednesday 23rd October) by Earthwatch found that of more than 2,300 sites measured, 61% showed poor water quality – with high levels of and nutrients including nitrate and phosphate.

The Anglian and Thames river basin districts had the worst water quality in the UK, with over 80% of surveys showing unacceptable nutrient concentrations. West Glamorgan in Wales and Kirkcudbrightshire in Scotland had the best water quality of those measured. In England, the county of Northumberland has the best water quality, whereas Rutland has the worst water quality in the UK.

Dr Sasha Woods, Director of Science and Policy at Earthwatch Europe, said: “The results of Septembers Great UK WaterBlitz are deeply concerning. The data analysed in this report shows the alarming extent of pollution in UK rivers with no region left untouched.

"Our rivers are facing a multitude of threats, including sewage pollution to agricultural runoff and we need urgent action to protect these vital ecosystems else we risk greater losses to freshwater biodiversity, the potential spread of anti-microbial resistance, and the very real threat of clean water scarcity. Healthy freshwater systems, free from harmful pollution aren’t a nice thing to have, they are vital if we are to address the biodiversity and climate crises.”

James Finnegan, Manager of the Flood & Coastal Risk Programme at the Environment Agency, said: “The Environment Agency recognises the benefit of citizen science. We see it complimenting Environment Agency monitoring to strengthen our understanding of whole-catchment systems. We’re pleased to work with Earthwatch to explore how citizen science data can support better decisions for our environment.”

The full report ‘Great UK WaterBlitz September Report’ is available online.