Common Drugs Pollute Rivers on Every Continent

Common Drugs Pollute Rivers on Every Continent

A global look reveals contamination by antibiotics, antidepressants and other medications

Yamuna River in New Delhi, seen in 2019, was one of the rivers sampled to determine what pharmaceuticals might be polluting them. Credit: Noemi Cassanelli/AFP/Getty Images

For more than 20 years scientists have known that the drugs we take, for maladies ranging from headaches to diabetes, eventually make their way into our waterways–where they can harm the ecosystem and potentially promote antibiotic resistance.

However, most research on pharmaceutical contaminants has been conducted in North America, Europe, and China. This has only examined a small number of compounds. It is difficult to compare the results due to the variety of analysis and sampling methods used in these studies. Scientists may be missing a significant piece of the puzzle regarding pollution due to these limitations.

A new paper published in the Proceedings of the National Academy of Sciences USA provides a more comprehensive look. A network of 127 scientists sampled 258 rivers in 104 countries for 61 different chemicals, producing “a sort of ‘pharmaceutical fingerprint’ of nearly half a billion people across all the world’s continents,” says study lead author John L. Wilkinson, an environmental chemist at the University of York in England.

Many rivers that were most drug-polluted were found in Africa and Asia. These rivers were “in areas and countries that are largely forgotten by scientists on this topic,” Wilkinson said. The waterways with the highest pharmaceutical concentrations were also found in countries of lower-middle income. The authors suggest that this could be due to improved medication access in areas that lack adequate wastewater infrastructure.

Four compounds–caffeine and nicotine, acetaminophen, acetaminophen, and cotinine–were found on every continent except Antarctica. Another 14, including antihistamines, antidepressants and an antibiotic, were traced on all continents except Antarctica. Some drugs were only found in certain places, like an antimalarial drug found in African samples.

Overall the study suggests that more global assessments of aquatic pollution are needed, especially for chemicals that pose a greater risk to human health, according to Elsie Sunderland, an environmental scientist at Harvard University who was not involved in the new research. She also said that the study suggests that we need wastewater treatment

Graphic shows average concentration of drugs in water sampled from rivers in each of 134 countries of various income levels.
Credit: Amanda Montanez; Source: “Pharmaceutical Pollution of the World’s Rivers,” by John L. Wilkinson et al., in Proceedings of the National Academy of Sciences USA, Vol. 119; February 22, 2022.

This article was originally published with the title “Mainstream Drugs” in Scientific American 326, 6, 21 (June 2022)

doi: 10. 1038/scientificamerican0622-21



    Andrea Thompson, an associate ed

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