Pharmaceuticals Found In Rivers In Every English National Park Study Finds

In a 2024 study by York University, found medicines including antibiotics, antidepressants and diabetes drugs are turning up in some of England's most protected landscapes, with a few sites more polluted than city rivers. What has Changed?

Researchers from the University of York and the Rivers Trust found pharmaceuticals in river water at 52 of 54 locations monitored across all ten of England's national parks. The peer-reviewed study, led by Professor Alistair Boxall, was published in Environmental Toxicology and Chemistry.

What the researchers found
The team tested 37 rivers for 54 active pharmaceutical ingredients (APIs). Samples were taken in duplicate in winter and summer 2022. They detected 31 of the compounds, in both seasons. Metformin, caffeine and paracetamol had the highest average concentrations. Cetirizine, metformin and fexofenadine were the most frequently detected.

Overall, levels in the parks were generally lower than those previously recorded in UK cities. There were notable exceptions. Antibiotic concentrations at sites in the Peak District and on Exmoor were higher than the levels thought to select for antimicrobial resistance in bacteria. Total pharmaceutical levels in those two parks exceeded those in most city rivers. On Exmoor, the River Exe at Exford recorded the second-highest level in the whole study, above readings from London, Belfast, Leeds and York.

Fourteen locations had concentrations of at least one of seven drugs above thresholds of concern for fish, invertebrates and algae, or for selecting antimicrobial resistance. The drugs were amitriptyline, carbamazepine, clarithromycin, diltiazem, metformin, paracetamol and propranolol. Levels in the Peak District, Exmoor, Lake District, South Downs and New Forest were potentially harmful to aquatic species.

The Peak District had the most APIs detected (29), and the Yorkshire Dales the fewest (seven).

Why national parks are vulnerable
Pharmaceuticals mostly reach rivers when people excrete them, though unused medicines flushed away or thrown out can also contribute. The authors point to several features of the parks that make the problem worse:

• Wastewater treatment works are often older and less effective at removing drugs.
• Low-flow rivers give less water to dilute what comes out of treatment plants.
• Tourism causes large seasonal swings in population.
• A relatively high proportion of residents are elderly.
• Some areas rely more on septic tanks and basic treatment facilities.

The researchers say the findings suggest a risk to wildlife and potentially to people who swim, paddle or canoe in the rivers. Those findings sit within a broader debate about the state of England's waterways.

Reaction and calls for action
Boxall has called on government, local authorities and the water industry to improve monitoring and invest in better treatment technology in the parks. The Environment Agency said it was working with other regulators and the water industry on Chemical Investigation Programmes, and noted that the EU had passed legislation making pharmaceutical companies, rather than bill payers, cover the cost of tackling this pollution. It said it wanted the UK Government to explore adopting a similar approach. The Campaign for National Parks has joined the researchers in pressing for tighter regulation. The authors also stress the need to improve monitoring and management of pharmaceutical pollution in similar protected areas worldwide. Members of the public are urged to return unwanted medicines to pharmacies rather than flushing them.

Where things stand two years after the study
The study remains the most comprehensive look at pharmaceuticals across all of England's national parks
The issue is still attracting research funding elsewhere in the UK.

In May 2026 the University of Nottingham was awarded £1.19m for a two-year project on pharmaceutical water pollution in Scotland, and the Pharmaceutical Journal cited the national parks study in its coverage.

Campaign for National Parks (CNP) has done the most, though mainly on advocacy.

• In August 2024 it teamed up with the study’s scientists to push for tighter regulation and better monitoring of national park waterways. cnp
• In September 2024 it ran an outdoor advertising campaign in six cities, saying every river, stream and lake in the 13 national parks of England and Wales is polluted. It cited the York study and asked the public to write to their MPs. signlinkprolificnorth
• It has also said it wants the UK Government to explore adopting the EU model, in which pharmaceutical companies rather than bill payers cover the cost of stopping this pollution. channel4

That campaigning is about water pollution in general only with mothing newer from CNP specifically on pharmaceuticals.
Defra has no pharmaceutical-specific action:

• Its reform agenda (the white paper and forthcoming Water Reform Bill, is the main route. It only touches pharmaceuticals through the possible polluter-pays/producer-responsibility scheme.
• The Environment Agency, which sits under Defra, said at the time that it was working with other regulators and the water industry on Chemical Investigation Programmes to understand how pharmaceuticals affect the water environment. channel4
• Defra’s Veterinary Medicines Directorate is currently under pressure on a related issue. The Exmoor Society says it has contacted Defra about insufficient action by the VMD on flea treatments containing fipronil and imidacloprid, which pollute rivers, and has responded to a House of Lords inquiry on them. That’s veterinary medicines, not the human drugs in the York study.

Defra has been asked for comment.

Reference: Boxall, A.B.A. et al. (2024), "Pharmaceutical Pollution of the English National Parks," Environmental Toxicology and Chemistry, 43, 2422–2435. DOI: 10.1002/etc.5973

Source: channel 4 / signlinkprolificnorth / Campaign for National Parks