UK rivers are the worst in Europe for chemical pollution from prescription drugs

UK rivers are Europe’s worst for chemical pollution from prescription drugs threatening wildlife, major global study finds

Paracetamol, caffeine and hay fever treatments are among the drugs that end up in the country’s rivers when sewage is discharged by water companies, with implications for animal and human health.

Scientists led by a team from the University of York found pharmaceuticals in all eight rivers they tested in the UK, including the Thames, Clyde and Ouse in a study in more than 100 countries.

The UK topped European countries for sites where at least one drug exceeded levels considered safe for aquatic life or antimicrobial resistance in humans.

The riskiest drugs are propranolol, a beta-blocker prescribed for anxiety, migraines and heart problems, which is thought to affect the growth and reproduction of fish, and the antibiotic clarithromycin.

Discharge of sewage into rivers

Scientists surveyed multiple sites on 258 rivers around the world to measure the presence of 61 pharmaceuticals, with 54 locations in the UK on eight different rivers, including the Ouse, Foss and River Dee.

Alistair Boxall, professor of environmental science at York, said the main source of pharmaceutical pollution in the UK comes from sewage runoff into rivers.

“Part of it has to do with how our sewage systems work,” he said. “Other countries are more sophisticated in the way they use wastewater.

“But the other big challenge we have is population density. We have a fairly densely populated country, with a complex river system.

“That means the dilution is not that great. Put that together and you start to see high concentrations of this stuff.

He added: “The worst case scenario will be the potential effects on fish growth and reproduction. Or the potential presence of antibiotics leads to the selection of resistant bacteria that could return to humans or animals, contributing to the antimicrobial resistance crisis.

The study also found that the UK has a high number of different chemicals in its rivers compared to others in Europe. The Clyde contained 31 of the 61 drugs included in the study, and the Thames contained 26.

Fexofenadine, a treatment for hay fever, metformin which treats type 2 diabetes, paracetamol and caffeine are the compounds detected at the highest concentrations.

“We’re releasing this cocktail of chemicals into our rivers and we don’t really know what impact it’s having on ecological health,” Boxall said.

Dr Rob Collins, Science and Policy Director of the Rivers Trust, said: “Many of our sewage treatment plants need upgrading and upgrading to be able to cope with the range of pharmaceuticals in our sewage systems.

Reed beds and wetlands

“Nature-based approaches, such as reedbeds and wetlands, also have a role to play and have been shown to be effective in trapping several pharmaceuticals in wastewater.

“While most pharmaceutical by-products in our rivers come from our wastewater, some have been discharged directly as a means of disposal.

“Greater public awareness is needed on this issue. Few people know that there is a drug take-back system where unwanted drugs can be returned to the pharmacy rather than flushed down the toilet.

Globally, the team found that pharmaceutical pollution contaminates water on every continent and at potentially toxic levels in more than a quarter of the sites studied.

They found that poorer countries tended to have higher concentrations of pharmaceuticals, although a handful of rivers in European cities rank in the top 50, including the Clyde, which ranks 26th out of 258 .

The Clyde was the most contaminated site in Europe, with the Manzanares River in Madrid leading the way.

The study was published in the journal Proceedings of the National Academy of Sciences.