Pollution of the world’s rivers from medicines and pharmaceutical products poses a “threat to environmental and global health”, a report says.
Paracetamol, nicotine, caffeine and epilepsy and diabetes drugs were widely detected in a University of York study.
The research is among the most extensive undertaken on a global scale.
Rivers in Pakistan, Bolivia and Ethiopia were among the most polluted. Rivers in Iceland, Norway and the Amazon rainforest fared the best.
The impact of many of the most common pharmaceutical compounds in rivers is still largely unknown.
But it is already well established that dissolved human contraceptives can impact the development and reproduction of fish, and scientists fear the increased presence of antibiotics in rivers could limit their effectiveness as medicines.
The study sampled water from more than 1,000 test sites in more than 100 countries.
Overall, more than a quarter of the 258 rivers sampled had what are known as “active pharmaceutical ingredients” present at a level deemed unsafe for aquatic organisms.
The two most frequently detected pharmaceuticals were carbamazepine, which is used to treat epilepsy and nerve pain, and metformin, used to treat diabetes.
High concentrations were also found of so-called “lifestyle consumables” like caffeine (coffee) and nicotine (cigarettes) as well as the painkiller paracetamol.
In Africa, artemisinin, which is used in anti-malarial medicine, was also found in high concentrations.
The report says the increased presence of antibiotics in rivers could also lead to the development of resistant bacteria, damaging the effectiveness of medicines and ultimately posing “a global threat to environmental and global health”.
The most polluted sites were largely in low- to middle-income countries, and in areas where there was sewage dumping, poor wastewater management and pharmaceutical manufacturing.