Quarter of world's rivers contain toxic levels of prescription drugs
A quarter of the world’s rivers contain potentially toxic levels of pharmaceuticals, a new study has found.
The new study looked at 258 rivers across the globe, including the Thames in London and the Amazon in Brazil, to measure the presence of 61 drugs.
In Britain, the Clyde is the worst-polluted with pharmaceuticals, the researchers found, according to The Times.
Researchers found that poor countries are more likely to have water dangerously polluted with drugs.
The researchers studied rivers in over half of the world's countries - with rivers in 36 of these countries having never previously been tested for pharmaceuticals.
The study is part of the University of York-led Global Monitoring of Pharmaceuticals Project, and is the first truly global-scale investigation of medicinal contamination in the environment.
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The researchers found that pharmaceutical pollution is now contaminating water on every continent - and some of the worst-polluted areas are sub-saharan Africa, South America and parts of southern Asia.
Co-leader of the project Dr John Wilkinson, from the Department of Environment and Geography, 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.
“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. This one study presents data from more countries around the world than the entire scientific community was previously aware of: 36 new countries to be precise where only 75 had ever been studied before."
"With 127 collaborators across 86 institutions worldwide, the Global Monitoring of Pharmaceuticals Project is an excellent example of how the global scientific community can come together to tackle large-scale environmental issues.
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The researchers say that the activities most associated with high levels of pharmaceutical pollution are rubbish dumping along river banks, inadequate wastewater infrastructure and pharmaceutical manufacturing, and the dumping of the contents of residual septic tanks into rivers.
The researchers found strong correlations between the socioeconomic status of a country and higher pollution of pharmaceuticals in its rivers (with lower-middle income nations the most polluted)
The study included noteworthy rivers such as the Amazon, Mississippi, Thames and the Mekong.
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Water samples were obtained from sites spanning from a Yanomami Village in Venezuela, where modern medicines are not used, to some of the most populated cities on the planet, such as Delhi, London, New York, Lagos, Las Vegas, and Guangzhou.
Areas of political instability such as Baghdad, the Palestinian West Bank and Yaoundé in Cameroon were also included.
The climates where samples were obtained varied from high altitude alpine tundra in Colorado and polar regions in Antarctica, to Tunisian deserts.
The researchers suggest their approach could also be expanded in the future to include other environmental media such as sediments, soils and biota, and could allow for the development of global-scale datasets on pollution.
