A recent study conducted by the University of Oxford has shed light on the severe impact of pollution from treated and untreated sewage, surpassing the damage caused by agricultural runoff.

These revelations have prompted a call for increased regulation of water companies and significant improvements in their treatment processes to safeguard the health of our rivers.

The study disclosed that not a single river in England meets the established standards for chemical and biological pollution. Furthermore, the government’s targets for enhancing water quality in rivers seem increasingly unattainable. The primary culprits behind this ecological crisis are sewage discharges.

“Improvements to wastewater plants should be implemented along with more regulations. These efforts are crucial in safeguarding the integrity and safety of our rivers – fundamental elements of both ecosystems and human wellbeing,” said the lead author, Dr Dania Albini, of Oxford’s biology department.

Water companies release treated sewage into rivers, while raw effluent finds its way into water bodies through storm overflows, primarily during exceptional circumstances. The harmful consequences of this are staggering, as it leads to elevated levels of nutrients, algae, and sewage fungus in rivers.

One of the most concerning aspects of sewage pollution is the profound disruption it causes to plant, animal, and microbe communities in river ecosystems. The study highlights that sewage discharge has a more detrimental effect on water quality and river-dwelling organisms than agricultural runoff, despite the latter’s known adverse impact.

This pivotal research has been published in the journals Global Change Biology and Ecological Solutions and Evidence, bringing the issue of sewage pollution to the forefront of environmental discussions.

Albini said: “Our study highlights the disproportionate impact that sewage discharge has on river quality, presenting an urgent need for a comprehensive action plan targeting the sewage discharge problem.”

The ongoing criminal investigation by the Environment Agency and an inquiry by the financial regulator Ofwat into water companies’ management of treatment plants underscores the seriousness of the situation. Water companies, responsible for treating sewage from households and businesses, must be held accountable for their role in the contamination of our rivers.

James Wallace, of the UK-based charity River Action, said: “This important research demonstrates yet again the damage from unregulated water companies and agriculture. In addition to the catastrophic impact on wildlife from nutrient pollution, the public should be aware that sewage systems do not remove dangerous bacteria such as E.coli and intestinal enterococci from treated sewage.

“When will the government make water companies and farms clean up their act, especially in places where human lives and sensitive protected habitats are threatened?”

In a related study led by Dr. Leon Barron from the Environmental Research Group at Imperial College, London, researchers collected hundreds of samples from 14 waterways in Greater London over a three-year period. Their findings revealed the presence of 21 compounds that posed potential risks to freshwater ecosystems. These pollutants encompassed antibiotics, pain medication, and pet parasite medications containing neonicotinoids. The study also identified water companies’ treatment plants and combined sewer overflows as the primary sources of chemical risks to rivers, underlining the gravity of the issue.

Smaller rivers that feed into the Thames were particularly affected by wastewater pollution, intensifying the urgency for remedial actions in these areas.

Furthermore, the study compared data gathered during the COVID-19 lockdowns with information collected as society reopened. This extensive research, focusing on a heavily urbanised river system, provided in-depth insights into London’s water quality. It underscores the pressing need for stringent measures to address sewage pollution and prevent further deterioration of our rivers.

In conclusion, the research conducted by the University of Oxford and Imperial College reveals a pressing environmental crisis caused by sewage pollution in England’s rivers. The evidence is clear: sewage discharge poses a more significant threat to river biodiversity and water quality than agricultural runoff, necessitating immediate action to regulate water companies and enhance treatment processes. Protecting our rivers is vital for the well-being of both ecosystems and communities.

Guy Woodward, a professor of ecology in the department of life sciences at Imperial, and a co-author of the paper, said: “This picks up on several [chemicals] that are at potentially harmful concentrations for wildlife, but which have seemingly been overlooked in traditional surveys of our water quality in urban areas at this resolution.”