Innovative UK-based study assesses pharmaceutical pollution in the world’s rivers and presents global perspective

The University of York has led a world-first study assessing the occurrence of pharmaceuticals in rivers around the world, monitoring 1,052 sampling sites in 258 rivers and 104 countries. This is the most extensive and holistic study of it’s kind – representing the “pharmaceutical fingerprint” of 471.4 million people in all continents. As many pharmaceutical concentrations exceeded eco-toxicological end-points, there is a threat to public and environmental health from this pollution in >25% of the studied locations.

It is the first time a direct global assessment of pharmaceutical pollution in surface water has been performed. This work was possible through an international collaboration of research teams – 127 authors representing 86 institutions worldwide. And development of a standardised analytical method at the University of York, which enabled accurate, robust and reliable quantification of pharmaceuticals in samples shipped from across the world. Thus concentrations were directly comparable – whereas previous global assessments of pharmaceutical pollutants were based on literature review, with studies performing different analyses and targeting different compounds.

You can find the full, open-access article published in Proceedings of the National Academy of Sciences of the United States of America

Available here:

Brief overview of results:

  • 61 pharmaceuticals and lifestyle compounds (e.g., caffeine, nicotine) were monitored, and carbamazepine, metformin, and caffeine were most frequently detected (>50% of sites). Highest concentrations were broadly observed for paracetamol, caffeine, metformin (antidiabetic), fexofenadine (antihistamine), sulfamethoxazole (antimicrobial), metronidazole (antimicrobial), and gabapentin (antiepileptic).
  • The most polluted sampling site was in the Rio Seke (La Paz, Bolivia), with a total pharmaceutical concentration of 297 µg/L. This was attributed to untreated sewage discharge and disposal of rubbish along the bank of the river. Pharmaceutical manufacturing was also attributed to high concentrations in other sites.
  • Highest total pharmaceutical concentrations were observed in sub-Saharan Africa, south Asia, and South America, and many of the most contaminated samples originated from low-to-middle-income countries. These locations were characterised by poor waste management, limited wastewater infrastructure, raw sewage discharge, and pharmaceutical manufacturing. Until this study, many of these countries had limited or no historic monitoring of pharmaceuticals in the aquatic environment (36 of the countries previously had no data).
  • At >25% of the sampling sites, compound concentrations were greater than predicted no-effect concentrations (PNEC), or exceeding minimum inhibitory levels which may drive selection for antimicrobial resistance. The antimicrobial sulfamethoxazole was frequently observed at levels above the eco-toxicological end-point, with a total of 140 of the sites exceeding the PNEC.
  • Statistical analysis based on socioeconomic variables found that pharmaceutical pollution was positively associated with population, median age, local unemployment, and poverty rates, and negatively associated with the death rate of a country. Population was found to be the most significant variable.

Although an assessment of environmental risk was performed, there remain critical knowledge gaps on the effect of pharmaceuticals in mixture – as exist in rivers around the world. Nonetheless, it was determined that the global presence of pharmaceuticals in surface water poses a threat to environmental and human health, and a risk to successful delivery of the United Nations Sustainable Development Goals.

It is research such as this which continues to drive the One Health Breakthrough Partnership’s mission to deliver a “non-toxic” environment, and reduce pharmaceutical pollution in the environment.

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