Great UK WaterBlitz finds 'cocktail of chemicals' in UK rivers

Great UK WaterBlitz finds ‘cocktail of chemicals’ in UK rivers

Thousands of volunteer citizen scientists across the UK braved the wettest weekend of the year, 20-23 September, to test their local rivers as part of the second Great UK WaterBlitz.

For this WaterBlitz, we joined forces with researchers from Imperial College London to test water samples for additional chemicals.

Key water quality findings:
  • The Anglian and Thames river basin districts have the worst water quality in the
    UK: over 80% of surveys showed unacceptable nutrient concentrations.
  • The data suggest the counties of West Glamorgan in Wales, and
    Kirkcudbrightshire in Scotland have 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.
Water pollution findings from Imperial College London:

A comprehensive analysis of 91 water samples revealed a concerning presence of various chemicals in UK freshwater bodies:

  • Pharmaceuticals: Antidepressants (venlafaxine), antibiotics (trimethoprim),
    and painkillers (tramadol and diclofenac) were detected in significant
    proportions of samples.
  • Agricultural Contaminants: Fungicides (tebuconazole) and pesticides
    (acetamiprid) were found in several samples, indicating agricultural runoff as a
    source of pollution.
  • Stimulants: Caffeine was found in all samples, almost all at a level posing risk
    to aquatic life. Nicotine was also found in a quarter of samples.

Many of these substances pose a significant risk to aquatic organisms. For example, antidepressants have been shown to affect reproductive cycles and motility. Nicotine has been demonstrated to be more harmful to fish than to aquatic insects, and the presence of antibiotics in freshwater bodies is known to contribute to Antimicrobial Resistance (AMR), a phenomenon where microorganisms no longer respond to available antimicrobial drugs. The full extent of the impact is still being researched.

The new data gathered will help to properly understand the complex cocktail of chemicals that pollute our fresh-water systems. These test results allow a full appreciation of the extent of the damage to date and how to mitigate future disasters brought about by an unhealthy eco-system.

Following the second Great UK WaterBlitz, Director of Science and Policy at Earthwatch Europe, Dr Sasha Woods, commented:

“The results of September’s 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.”

Owen Lewis, Deputy Director for Water Analysis and Reporting for the Environment Agency, said:

“The Environment Agency values the contribution of England’s growing network of citizen scientists and welcomes the Great UK WaterBlitz and other initiatives that complement our own research, monitoring and assessment work.

“We are absolutely committed to improving water quality, which is why we are pleased to be working closely with Earthwatch to target research and help find solutions to the complex problems water is facing.”

Dr Leon Barron, Reader in Analytical & Environmental Sciences within the School of Public Health at Imperial College London, said:

“We’re delighted to be a partner in this year’s WaterBlitz. 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.”

This year, Earthwatch Europe also partnered with the WI and over 500 members went out to test over the weekend event. Melissa Green, Chief Executive of WI, said:

“We are delighted to support the Great UK WaterBlitz during our WI Week of River Action this September. WI members care greatly about our environment and are passionate about putting an end to the disastrous pollution of our rivers. Since our ‘Clean Rivers’ campaign was launched by members at our Annual Meeting last year, the WI has been busy calling for stronger regulators, promoting bathing water designations and making waves in their communities. We know that not enough is happening to stop river pollution, and that we need better data, so WI members are eager to get out to their local rivers and get stuck in to contribute to a solid, up to date picture of this horrible situation.”

Citizen science has the power to generate vast, accurate water quality data, but regular testing is key. Join us for the next Great UK WaterBlitz in Spring 2025, register your interest on our website: www.earthwatch.org.uk/greatukwaterblitz

You can read the full September Great UK WaterBlitz report below.

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