The pharmaceutical pollution

Pharmaceuticals in the environment: The global challenge of pharmaceutical pollution and how governments, industry, prescribers, and patients can respond

Ever wonder where all our medicine goes? Medicines, or pharmaceuticals, are used in human healthcare, veterinary care, agriculture, and aquaculture. We consume them, excrete them, throw them into landfills, administer them to livestock, and sprinkle them into soil and fish farms. And these medicines, that are meant to treat us, ultimately end up in our natural environment – with profound consequences for our ecosystems and human health. This article unpacks the problem of pharmaceuticals in the environment and then turns to what can be done about it, from reforming regulations and industry innovations, to changes in healthcare and farming practices. 

How pharmaceuticals end up in the environment

Pharmaceutical use is widespread and rising. Human use of pharmaceuticals, currently amounting to around 3.8 trillion doses per year, is estimated to increase by 38% by 2028. This rise is driven by a range of factors: aging populations, changing disease patterns, advancements in drug development, improved diagnostic techniques, greater access to pharmaceuticals, and growing use of pharmaceuticals for prevention. Some estimates suggest that pharmaceuticals are used in even higher quantities in other sectors. For example, approximately 73% of antibiotics administered globally are used in agriculture, while 5.7% are used in aquaculture. As food production continues to intensify to meet demands of a growing population, it is likely that pharmaceutical use in these sectors will also continue to rise.

The pharmaceuticals that we use across various sectors enter the environment in several ways. The most common route is simply through use: when humans (and animals) consume medicines, not all of the active ingredients are absorbed. A significant proportion is excreted – sometimes up to 90% – into sewage systems or directly into soil and water where sanitation systems are poor. Improper disposal also plays a role. Many people flush unused pills down the toilet or throw them into household bins, where they leach into groundwater or landfills. Factories producing pharmaceuticals release residues in wastewater, particularly in countries where manufacturing environmental regulation is weak. Additionally, pharmaceuticals used in agriculture and aquaculture, such as antibiotics and hormones in livestock feed or for fish farming, run off directly into surrounding ecosystems. 

The result is a cocktail of active pharmaceuticals in the environment. More than 900 types of pharmaceutical residues have been detected in the environment – everywhere from urban rivers in Europe to remote highlands in Asia. In some places, pharmaceutical concentrations are staggering. A study of a river near Hyderabad, India, found levels of the antibiotic ciprofloxacin so high that the water could theoretically treat 44,000 people. Once in the environment, pharmaceuticals undergo changes. They can degrade or persist, transform into by-products, or be transported to other environmental compartments. And if, after these changes, their concentrations exceed certain ecological thresholds, there is the potential for them to do harm. 

The effects of pharmaceuticals on ecosystems and human health

Pharmaceuticals are designed to have powerful biological effects, so when they enter ecosystems, the impact is rarely neutral. Three categories of pharmaceuticals in the environment illustrate the scale of the problem:

1. Antibiotics and antimicrobial resistance (AMR): When antibiotics seep into water or soil, they create “hotspots” where bacteria are exposed to low but persistent doses. This exposure accelerates the evolution of resistant bacteria strains, fuelling antimicrobial resistance – a crisis the WHO calls a “silent pandemic”. Resistant infections already kill nearly 5 million people annually, with projections of 39 million deaths by 2050 if trends continue. AMR is, therefore, being quietly amplified by antibiotic-contaminated soil, rivers, and effluent streams worldwide. 
2. Hormones and endocrine disruption: Synthetic hormones from birth control pills, hormone replacement therapy, or growth promoters in livestock feed can interfere with reproductive systems in wildlife. Male fish, for example, exposed to trace amounts of oestrogen in rivers have been found to develop female characteristics, including producing eggs. Such disruptions ripple through food webs, altering species survival, and undermining biodiversity.
3. Painkillers and anti-inflammatories: Medicines like diclofenac and ibuprofen, widely used to treat pain in humans, pets, and livestock, have been shown to damage kidneys in fish, impair reproduction in molluscs, and deform frog embryos. One of the most tragic cases of ecological harm from painkillers occurred in the 1990’s when more than 95% of Southeast Asia vulture species, feeding on livestock carcasses treated with diclofenac, died from kidney failure. The collapse of these vulture species led to the deaths of half a million people from diseases like rabies, as stray dog populations exploded in the absence of vultures, with an economic fallout of $68 billion. 

These examples show that pharmaceutical pollution is already altering ecosystems, endangering species, and harming human health.

What can be done?

Unlike many pollutants, pharmaceuticals are essential to modern medicine – we cannot simply ban them. The challenge is to protect both humans and the planet. Considering that once pharmaceuticals enter the environment their fate and impact are dependent on complex and dynamic variables, efforts to mitigate their impact are better focused on reducing the production and use of pharmaceuticals and controlling the entry of consumed or disposed pharmaceuticals into the environment. Action to optimise production, use, and disposal is required by a range of stakeholders: regulatory bodies, pharmaceutical manufacturers, healthcare providers and prescribers, and patients.

National, regional, and international regulation on pharmaceutical pollution is sporadic but increasingly emerging in recognition of the threat posed. Some countries now require Environmental Risk Assessments (ERAs) before new drugs are approved, evaluating how a medicine might behave once it enters the environment. Europe has made this process more stringent in recent years, while the WHO issues global guidance on managing pharmaceutical pollution. Unfortunately, regulations vary widely between countries, creating loopholes where pharmaceutical pollution (e.g., from production) can be outsourced to regions with weaker regulatory standards, monitoring, and enforcement. More robust, harmonised international standards are urgently needed.

Despite varying regulation, pharmaceutical manufacturers are increasingly acting to reduce their pharmaceutical pollution. For example, some companies are experimenting with “green chemistry”, designing drugs that are biodegradable and break down safely after use. Others are investing in advanced wastewater treatment technologies, like activated carbon filtration and membrane bioreactors, that can capture residues before they escape into the environment. Industry collaborations on pharmaceuticals in the environment also exist. The AMR Industry Alliance, for example, brings together over 100 companies to address antibiotic pollution. Challenges persist, however. Upgrading wastewater treatment plants is expensive (and not always perfect at filtering residues before they reach the environment) and regulation often discourage changes (e.g., green chemistry) to existing pharmaceutical products. 

A large share of human pharmaceutical pollution comes from patient use. Reducing unnecessary prescriptions is therefore crucial. The concept of rational prescribing – giving the right drug, at the right dose, for the right duration – has been around since the 1980’s. More recently, educators, health practitioners, and policymakers have argued rational prescribing should also consider the environment. For example, if two drugs are equally effective but one is more environmentally harmful, prescribers could favour the greener option. Efforts are underway to embed this thinking into medical education. For example, the UK’s medical body, the General Medical Council, now requires sustainability to be part of medical training, and EU-funded projects are teaching prescribers how to consider environmental impacts.

Patients also have a role to play. Proper disposal is vital. Instead of flushing or throwing away unused pills, many pharmacies now run take-back programmes where patients can return their unused medicines for safer disposal. In some countries, schemes to re-dispense unused medicines have cut pharmaceutical pollution dramatically. For example, in the Netherlands, reusing unopened cancer drugs reduced pharmaceutical waste by 68%, while also saving patients money. Regulatory barriers to reuse, however, mean such practices remain rare.

Finally, pharmaceutical pollution from agriculture and aquaculture requires action by these sectors. Some regions are beginning to ban the routine use of antibiotics as growth promoters, while encouraging better hygiene, vaccination, and selective livestock breeding to reduce reliance on medicines. Farmers are also experimenting with biofilters, constructed wetlands, and composting systems that capture and break down residues in manure or aquaculture wastewater. Innovative approaches like aquaponics, which use fish waste as fertilizer for plants, can create closed loops that reduce the need for pharmaceuticals and, therefore, pharmaceutical leakage into the wider environment. 

Conclusion

Pharmaceuticals – that save lives and fuel our food systems – can, if unmanaged, disrupt ecosystems, with disastrous effects on human health. Reducing pharmaceuticals in the environment requires coordinated action across sectors and borders: governments must strengthen and harmonize regulation; industry must innovate in drug design, optimise wastewater treatment, and improve transparency of medicines environmental impact; healthcare providers must practice rational, environmentally informed prescribing; patients must use and dispose of medicines responsibly; and farmers and veterinarians must adopt practices that reduce reliance on pharmaceuticals. Underlying all these actions is the need for education and awareness. The more we recognise the hidden life of our medicines beyond the pharmacy shelf, the better we can design systems that protect both human health and the natural world.