Sub-Saharan Africa is one of the regions most affected by drug pollution ending up in the world’s rivers, according to a study of water samples from around the world.
The research, led by scientists from the University of York in the UK, included samples taken from 258 rivers in 104 countries. As part of the Global Pharmaceutical Monitoring Project, one of the research objectives was to collect data from places like Yaoundé, Cameroon or the deserts of Tunisia, where monitoring of drugs in sources of water has long been neglected.
“We have known for more than two decades now that pharmaceuticals enter the aquatic environment where they can affect the biology of living organisms,” said project leader Dr John Wilkinson. “But one of the biggest problems we’ve faced in solving this problem is that we haven’t been very representative when monitoring these contaminants.”
At least 24 African countries were included in the research, which was published recently in the journal Proceedings of the National Academy of Sciences (PNAS). Some of the hardest hit cities included Addis Ababa in Ethiopia, Tunis and Nairobi, Lagos in Nigeria and Kinshasa in the Democratic Republic of Congo.
High levels of the drug were also found in the waters of Accra in Ghana and Luanda, Angola, while test sites in The Gambia and Zimbabwe detected some of the lowest levels on the continent. Drug levels were highest in places where sewage management infrastructure is limited and waste dumped along the river bank is common.
Globally, the researchers report that about 25% of sites had potentially harmful levels of pharmaceuticals in the water. These drugs included propranolol, a common high blood pressure drug; the allergy medicine loratadine; and ciprofloxacin, one of two antibiotics widely detected at high levels.
A total of 41 of the 61 drugs or compounds targeted in the study were present in samples from the African continent.
Image: Nairobi River, Global Pharmaceutical Monitoring Project