From the Amazon River to the Thames, from the Mississippi to the Mekong: the rivers of all continents are now polluted by drugs, with potential risks for the environment and human health.
Dozens of substances detected: in the lead there are carbamazepine, used for epilepsy, and metformin, used against diabetes.
To map their distribution on a global scale is a research conducted on water samples taken in over a thousand locations along 258 rivers in 104 countries and conditioned by the lifestyle habits of over 471 million people.
The study, coordinated by the British University of York, is published in the journal of the American Academy of Sciences (PNAS).
The work was carried out in collaboration with 127 researchers from 86 scientific institutions around the world as part of the 'Global Monitoring of Pharmaceuticals Project': the initiative has expanded significantly in the last two years, to produce this study, the first conducted truly on a global scale to assess environmental contamination due to medicines.
In fact, the researchers examined the rivers of more than half of the countries of the world, 36 of which had never been evaluated so far for the presence of pharmaceutical residues.
Water samples were taken in the most disparate places: in a village of the Yanomami Indians in Venezuela (where drugs are not used) as well as in the most populated cities on the planet, such as Delhi, New York and Guangzhou.
The results of the analyzes show that the most contaminated rivers are found in low- and middle-income countries, especially in areas where waste and wastewater management is neglected.
High levels of contamination are associated with regions where the average age of the population is more advanced and where unemployment and poverty rates are highest.
Of the 61 substances monitored, 53 were found in at least one sampling location: of these, 4 were observed on all continents.
Carbamazepine was found in 62% of the samples (i.e. in 652 locations on all continents except Antarctica), followed by metformin (50%) and caffeine (50%).
The highest cumulative concentrations of active pharmaceutical ingredients were observed in sub-Saharan Africa, South Asia and South America.
The most contaminated site in the world is that of La Paz in Bolivia, along the Rio Seke, with a concentration that is 115 times higher than that of the East River in New York.
The largest number of substances (34) was found in the Kai Tak River in Hong Kong.
In contrast, Iceland is the only country where not even one of the 61 test substances was found.
Overall,
