UK rivers, soils, crops and drinking water are now so contaminated with human medicines that the country needs a “national mitigation strategy” for tackling pharmaceutical pollution, a group of scientists has warned.

Residues of drugs such as antibiotics, anti-depressants and hormones are flooding into the environment, the scientists said, contributing to biodiversity loss and risking public health.

In a briefing published last month, researchers from the University of Exeter said that pharmaceutical pollution has been detected at “ecologically unsafe concentrations” across many UK environments, including the country’s national parks. They cited studies showing hormones from contraceptive pills causing fish to change sex and affecting reproduction, anti-depressants altering fish behaviour, and antibiotic pollution fuelling the spread of drug- resistant “superbugs”, a major threat to human health.

Medicine-related pollution enters the environment through numerous routes, but the largest source is sewage, the briefing stated, with many drugs not being removed effectively at wastewater treatment plants. Unused drugs being disposed of domestically (as opposed to being returned to pharmacies, for example) also contribute to the problem, as do UK manufacturing and healthcare facilities. These sites produce high concentrations of pharmaceutical waste, much of it discharged via wastewater into the national sewage system.

According to the authors, the situation is expected to get even worse as the UK’s use of pharmaceuticals rises: in 2024 the UK’s pharmaceutical market was valued at a whopping £47 billion, a figure expected to rise to £68 billion by 2030.

To tackle the problem, the scientists, working in conjunction with the new charity Pharma Pollution Hub, devised a set of more than 30 “intervention points” – involving environmental, economic and health related policies – that they say should form the basis of a “national action plan”.

Amongst the proposals were increasing the resources dedicated to monitoring, and improving the rules around manufacturing waste and sewage sludge. 
UK corporate sustainability should be strengthened, the authors said, including aligning with (tougher) EU rules on the issue. Market-based incentives, such as tax breaks, should also be examined to help encourage environmentally responsible pharmaceutical supply.

The farming link

What’s all this got to do with food production and farming? Well, one of the key contamination vectors highlighted by the Pharma Pollution Hub is the use of sewage sludge as agricultural fertiliser. The scientists said that treated sludge removed in the wastewater treatment process is often used to create biosolids that are in turn applied to agricultural fields, providing a diffuse source of pharmaceuticals into the environment.

Indeed, water industry records passed to the AGtivist this month starkly highlight the scale and nature of the issue, detailing test results for sampling carried out around 139 sewage treatment works across large parts of the UK between 2016 and 2021. The tests identified more than 13,500 residues of antibiotics – and other chemicals, including the controversial weedkiller glyphosate – in treatment effluent, in rivers, and in sludge that had been applied to land, as well as other locations at treatment sites.

Amongst the antibiotics that were detected in waste spread to fields was ciprofloxacin, a critically important drug that is used to treat urinary tract infections, chest, skin and bone infections, sexually transmitted diseases, eye and ear conditions, as well as other illnesses. Another antibiotic found in fertiliser was azithromycin, deployed against pneumonia and bronchitis and other conditions.

Drugs used in veterinary medicine were also detected in the tests, including tylosin, a substance that is frequently administered in the pig and cattle sectors. (Waste from animal and meat processing operations can end up in treatment works, a potential vector for livestock antibiotic residues.)

The rise of superbugs

The pollution of water and soils with such residues can encourage the development and spread of antibiotic-resistant bacteria – so called “superbugs” because bacteria present in the water or ground can develop resistance to those substances – rendering the drugs ineffective against disease. These “superbugs” can in turn circulate further to ultimately affect humans and animals.

Antibiotic resistance is a major, and growing, public health emergency. The environmental spread of resistance is just one part of the issue, with the more significant drivers being the use and overuse of drugs in the treatment of humans and animals.

Recent surveillance data published by the UK’s Health Security Agency showed that the number of antibiotic-resistant infections in 2024 equated to an average of almost 400 newly reported cases per week.

Cases of bacteraemia (where infections are present in the bloodstream) caused by antibiotic-resistance were found to have increased from 18,740 cases in 2023 to some 20,484 cases in 2024. The estimated number of deaths in people with resistant infections also increased, rising from 2,041 in 2023 to 2,379 in 2024, an increase of 338 deaths in a single year.

Globally, the picture is bleak, and estimates have suggested that by 2050, death rates from resistant infections will have doubled from those of today, with figures indicating that almost 40 million people will lose their lives to “superbugs” over the next 25 years.

Chemical cocktail 

The use of sewage sludge as fertiliser on UK farms has come under growing scrutiny in recent years, less so because of pharmaceutical residues and more because of increasing evidence suggesting that the fertiliser can contain a nasty cocktail of microplastics, heavy metals, and so-called PFAS “forever chemicals”, which pose major environmental and health risks.

An investigation by Greenpeace found that as much as 78% of the country’s treated sludge – some 3.6m tonnes – was being spread over agricultural land each year, but that regulations around the practice were woefully out of date, having not been updated to reflect many of the contaminants contemporary sludge can contain.

The investigation also highlighted that sludge was not being routinely tested for contaminants before land spreading, and that, particularly worryingly, there were no legal limits in place around the volumes of chemicals that could be present in sludge spread onto farmland, representing a potential risk to the safety of the food chain.

Campaigners subsequently described the problem as a “ticking environmental time bomb” and warned that it could lead to soils ultimately becoming unable to support crop growth. They accused the water industry responsible for sewage treatment of “quietly offloading” waste onto UK farmland for years, “with little accountability and woefully inadequate oversight.”

They also said water companies have not been upfront about what sludge contains, meaning many farmers have unknowingly spread the waste across their fields whilst regulators “turned a blind eye”.

In response to these mounting concerns, raised as the wider UK river pollution scandal unfolded, the Government did  announce recently that it would “consult on how sewage sludge use in agriculture is regulated”. And last year, a report by the Independent Water Commission found that “greater environmental protection is needed to address the impact of modern contaminants that may be present in sludge… This should provide greater assurance both to the public and to farmers who accept sludge.”

Critics say this is all well and good but that the risks have been known about for years and little action has been taken, despite the numerous warnings. Given the evidence about just what the sewage sludge being applied to our fields contains, one has to ask: is it too little, too late?