Pharmaceuticals are essential to our well-being. However, pharmaceutical pollution is a source of growing concern. In a recent study, pharmaceuticals were detected in rivers across Ireland.
This form of pollution can be extremely hazardous to both animal and human welfare. Continue reading to learn more about the issue and the steps being taken to address it.
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How Do Pharmaceuticals Get Into Our Water?
Emissions of pharmaceuticals can happen in different ways. For example, during drug manufacturing, through urine and faeces, or by disposal of unused drugs. Wastewater treatment plants aim to remove unwanted material from water. However, they are not always successful for all materials. The removal efficiency of pharmaceuticals can be as low as 40% for some antibiotics. This isn’t a hypothetical gap either: a 2025 EPA report found that almost 60% of all wastewater discharged from Irish treatment plants does not consistently meet the standards required to prevent pollution.
Factors causing increased levels of pharmaceutical pollution in water include:
Investigating Pharmaceuticals in Irish Rivers
A 2024 study from Dublin City University (DCU) reported that Irish rivers contain pharmaceuticals. Surface water samples were collected from locations recommended by the Environmental Protection Agency (EPA). The study focused on four rivers – the Liffey, Nore, Suir and Annalee.
Professor Fiona Regan, director of the DCU Water Institute, reported: “We analysed 16 pharmaceuticals based on their presence in European rivers and found them in all the rivers we sampled.”
Some drugs that feature are:
- 17α-Ethinylestradiol (EE2) (oral contraceptive)
- Diclofenac (anti-inflammatory)
- Venlafaxine (antidepressant)
- Sulfamethoxazole (antibiotic)
The Dangers of Pharmaceutical Pollution
The drugs in Irish rivers listed above can harm animal and human health as follows:
EE2: A long-term study in Canada saw the ‘feminisation’ of male fish due to EE2. This phenomenon led to the near extinction of the species from the lake.
Diclofenac: A drug used in cattle, diclofenac is toxic to vultures in tiny doses. Vultures are also at increased risk of consuming residues of the drug in dead livestock. Due to diclofenac, vulture populations have declined in Southeast Asia.
Venlafaxine: This antidepressant was the drug detected the most in the Irish river study. Research shows that venlafaxine can cause behavioural and developmental changes in fish.
Sulfamethoxazole: High concentrations of antibiotics in water can cause antimicrobial resistance (AMR). AMR can lead to the development of drug-resistant ‘superbugs’, which have been found in Irish rivers. AMR was responsible for 1.27 million deaths in 2019 alone.
The EU’s Plan to Fight Pharmaceutical Pollution
The EU is working to better monitor and reduce pharmaceutical pollution in European waters. One way it does this is by updating a watchlist of harmful chemicals found in rivers, lakes, and seas. These pollutants can affect both the environment and human health. In early 2025, the watchlist was updated to include many pharmaceuticals.
To help remove these pollutants, a revised EU law will make quaternary treatment a legal requirement at large wastewater plants. This fourth treatment stage targets chemicals and medicines that earlier steps miss. Ireland must transpose this law into national legislation by 31 July 2027, with the largest plants required to introduce quaternary treatment on a phased basis between 2033 and 2045.
Under the law’s “polluter pays” approach, pharmaceutical and cosmetics manufacturers will fund most of the cost. This element has proven controversial and is now the subject of legal challenges at EU and Irish level. We cover the funding dispute and its implications for Irish industry in more detail here.
Conclusion for Pharmaceutical Pollution in Irish Water
Quaternary water treatment to remove pharmaceuticals from water will only be widespread by 2045. This means it will take roughly 20 years before this essential water treatment is in use across the EU. As a result, alternative “short-term” strategies are needed.
Testing for medicines in water is possible today, and it can help monitor pharmaceutical pollution and inform corrective action ahead of full quaternary treatment rollout. At Southern Scientific, we’re INAB-accredited and analyse over 10,000 drinking water samples annually, alongside a full range of wastewater and environmental testing. We can help companies detect and quantify drugs in their wastewater.
