The River Clyde has been named as the 'most contaminated' by pharmaceuticals in the UK in a new study.
The University of York study, published in the Proceedings of the National Academy of Sciences (PNAS), looked into pollution of rivers across the world by medicinal chemicals such as pharmaceutical drugs.
The study looked at 54 sampling locations on 12 rivers in the UK, detecting pharmaceuticals in all but four sites. The River Clyde was found to be the most contaminated site in the UK.
Co-leader of the project Dr John Wilkinson, from the University of York, said: "We've known for over two decades now that pharmaceuticals make their way into the aquatic environment where they may affect the biology of living organisms.
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"But one of the largest problems we have faced in tackling this issue is that we have not been very representative when monitoring these contaminants, with almost all of the data focused on a select few areas in North America, western Europe and China.
"Through our project, our knowledge of the global distribution of pharmaceuticals in the aquatic environment has now been considerably enhanced."
The study found that potentially toxic levels of pharmaceutical drugs in a quarter of river locations examined across the world, with researchers surveying more than 1,000 sites on 258 rivers including the Clyde, such as the Thames and the Brazilian Amazon.
The assessment measured the presence of 61 pharmaceuticals, including some compounds also linked to lifestyles such as caffeine, and whether they were above levels where they could have an effect on the environment.
The analysis found pharmaceutical pollution in rivers on every continent, with nicotine and cotinine, caffeine and paracetamol turning up everywhere including Antarctica, while an array of chemicals such as beta blockers, antibiotics, antidepressants, sleeping medication and antihistamines were found in rivers on all inhabited continents.
