Scientists pour cold water on claim British rivers are ‘cleanest since Industrial Revolution’

Scientists and charities have poured cold water on recent claims that water quality in British rivers is “better than at any time since the end of the Industrial Revolution”.

Although progress has been made in reducing some pollutants over the past three decades, a new study shows a mixed picture, and does not comprehensively support these claims. Available water quality data indicate that rivers downstream from major towns and cities have seen improvements in the levels of some pollutants, but local pressures remain, often from combined sewer overflows. In addition, many new pollutants, such as pharmaceuticals and personal care products, are not routinely monitored and are likely to be on the rise, as demand for these products has grown over time.

In areas with intensive agriculture the water quality of rivers today is more affected by agrochemicals such as pesticides and nitrogen fertilisers than it was before the 1960s.  

A comprehensive review of the Industrial Revolution claim has been published in the journal Science of the Total Environment, authored by researchers from the universities of Leicester, Durham, Cardiff, Bristol, York and Stirling as well as WWF-UK, the UK Centre for Ecology & Hydrology, The Rivers Trust, The Angling Trust, and the USA’s Ronin Institute.

The scientists collated available, often very limited, data for seven different categories of water pollutants from the late 19^th Century up to the present day, combined with insights into historical population growth, industrial activity and wastewater treatment provision, as part of the analysis. 

The researchers noted that, while levels of some pollutants probably peaked at some point between the 1960s and the mid-1990s and have since declined, water quality is still “unacceptably poor” in multiple areas across the UK, and there are signs that recent progress to tackle pollution has stalled. Levels of nitrate in many catchments remain high, and levels of most synthetic organic pollutants are unknown.  

The authors of the study have called for urgent improvements to water quality in many rivers and streams, as well as enhancements to monitoring programmes, including increased frequency and geographical spread of sampling and including a wider range of pollutants in routine analyses.

Mick Whelan, Professor of Environmental Science at the University of Leicester and corresponding author for the review, said: “Data for many pollutants show that concentrations are, indeed, likely to be lower than they were in the 1960s and 70s. Legislation such as the European Urban Wastewater Treatment Directive have clearly played a very important role in cleaning up our rivers from the mid-1990s. However, we have very little understanding about the impacts of many contaminants because we just don’t look for them routinely.”

Professor of Ecology at Cardiff University’s School of Biosciences, Steve Ormerod, added: “This comprehensive overview of water quality highlights concerning findings for Wales. It confirms how effective regulation has helped to tackle major historical problems – notably acid rain or the sewage outfalls that once led to 70% of rivers in the South Wales Valleys being classed as grossly polluted. At the same time, it reveals the need to get a far stronger grasp of issues such as combined sewer overflows, emerging pollutants such as microplastics and intensifying agriculture which appears to be degrading internationally important Welsh rivers such as the Wye.”

Dave Tickner, Head of Freshwater at WWF, said: “Our rivers provide vital habitats for precious species from salmon to otters to water voles. With nature in catastrophic decline globally, we should be doing everything in our power to make sure our rivers are in good health – this is critical if governments across the UK are going to meet commitments to boost nature by 2030.

“Rather than relying on sweeping claims about the state of our rivers, we need water companies, regulators and ministers to step up and enforce the rules designed to clean them up.  

“That means holding polluters to account and tackling the farming practices that have flooded our waters with harmful chemicals – this must be part of a wider effort to accelerate the shift to nature-friendly farming across the country.”

‘Is water quality in British rivers “better than at any time since the end of the Industrial Revolution”?’ is published in Science of the Total Environment.