Madrid is the European city most polluted by drugs in Europe, according to a new global study on the concentrations of active pharmaceutical ingredients (API) in 258 rivers. With an average of 17.1 µg/L, the Spanish capital occupies rank 14 of 137 worldwide, in a list headed by Lahore (Pakistan), La Paz (Bolivia) and Delhi (India).
Published in the journal PNAS by a team of international researchers, the report has analyzed samples from 1,052 locations in 104 countries, which represent the environmental influence of 471.4 million people. Rivers such as the Amazon, the Mississippi, the Thames and the Mekong have been sampled in places such as a Yanomami village in Venezuela.
According to the results of the investigation, exposure to these substances poses a danger in more than a quarter of the locations studied. Thus, these rivers present, at least, an API that exceeds the levels considered safe for aquatic organisms.
The study is part of the Global Pharmaceutical Surveillance Project, led by the University of York (Canada), and involves world’s first research of drug contamination in the environment.
Africa, Asia and South America: the most polluted
The results, which have collected 61 API, have indicated that the highest accumulated concentrations of these pollutants were observed in points of the Sub-Saharan Africa, South Asia and South Americain low- and middle-income countries, and in areas associated with poor wastewater and waste management infrastructure.
In North America, these were obtained in a campaign in San Jose Costa Rica. On the other hand, the most contaminated samples from Oceania came from a campaign in Adelaide (Australia) (mean 0.577 µg/L).
According to scientists, environmental exposure to these active ingredients can have negative effects on the health of ecosystems, but also on that of human beings.
Pharmaceutical contamination affects all continents
The study has pointed out that pharmaceutical contamination affects water on all continents. The active pharmaceutical ingredients most frequently detected in the analyzed rivers are the antiepileptic carbamazepinethe antihyperglycemic metformin and the caffeine.
Other contaminants found in potentially harmful concentrations include propranolol (for heart problems such as hypertension); the sulfamethoxazole (antibiotic against bacterial infections) or the loratadine (antihistamine). The highest concentration for any API is the paracetamol at a sampling site on the Río Seke (La Paz), where the team observed evidence of septic tank depletion and garbage dumping upstream of the sample collection site.
“They can affect the biology of living organisms“
The researchers hope that by increasing surveillance of pharmaceuticals in the environment, develop strategies to limit the effects potentially caused by the presence of pollutants. For his part, the co-director of the Global Pharmaceutical Surveillance Project, John Wilkinson, has stated that it has been known for more than two decades that pharmaceuticals reach the aquatic environment, where “they can affect the biology of living organisms” .
However, most of the available data was focused on “a few areas” in North America, Western Europe and China, although with this new project the knowledge about the global distribution of pharmaceuticals in the aquatic environment “has increased considerably”.