The drugs that people use end up in the rivers. Scientists from the University of York (UK) conducted a large-scale study and found that more than a quarter of the water arteries on the planet are contaminated with traces of drugs . This scientific work — as part of the Global Drug Monitoring Project.
Samples were taken and analyzed from 258 rivers flowing through the territory of 104 states (that is, in more than half of the countries of the world). The report included, for example, the Amazon, Mississippi, Thames and Mekong. Samples were taken from intact Indian settlements in Venezuela, where modern drugs are not used, and from densely populated metropolitan areas like Delhi, London, New York and Guangzhou. The climatic zones from which the samples were taken also varied — from the highlands and polar regions to the Tunisian deserts.
What were found in the rivers?
Water samples were tested for the presence of 61 drugs. It turned out that pharmaceutical contamination is present in rivers on all continents. The most common are carbamazepine (an antiepileptic drug, mainly used as an anticonvulsant), metformin (used in the treatment of type 2 diabetes) and caffeine.
However, other drugs were contained in potentially dangerous concentrations in water samples. There are four:
- sulfamethoxazole (an antibiotic to treat bacterial infections);
- propranolol (used for high blood pressure and heart problems – angina, tachycardia, etc. .);
- ciprofloxacin (an antibiotic widely used in clinical practice);
- loratadine (a very popular antihistamine used for allergies).
Where are the dirtiest rivers?
The highest concentrations of the drug are found in rivers in sub-Saharan Africa, as well as in southern Asia and South America. The level of pollution was directly related to the low and middle income levels of the population, as well as the poorly developed infrastructure for sewage treatment and waste treatment. The higher the unemployment and poverty level of the country's population, the dirtier the water there.
Of the Russian rivers, only the Moskva River appeared in the study of British scientists. According to the number of drug traces on it, it was somewhere in the middle of the rating. In general, the scale of pollution of Russian rivers, according to scientists, cannot be called significant. Previous studies have shown low concentrations of — several micrograms or even nanograms per litre. And it wasn't regular pollution, but most likely one-time emissions.
How dangerous are these pollutions?
In about a quarter of the places where UK scientists took water samples, the concentration of at least one drug exceeded the safe level for living organisms in the rivers. As the researchers write, in some parts of the world this figure is so high that it “poses a global threat to nature and human health”.
First, high concentrations of pharmaceuticals in rivers can affect the reproductive functions, behavior and physiology of aquatic life. This can manifest itself, for example, in changes in heart rate. Secondly, the pollution of rivers with antibiotics leads to the fact that bacteria resistant to them develop in the water. And when they enter the human body, these types of antibiotics will no longer be able to destroy them, they will be ineffective.
“With drugs it usually goes like this: we take them inside, they produce the desired effect on our body and are excreted from it. Now we see that even the most modern treatment facilities are not able to fully break down these compounds, and they end up in rivers and lakes, — said study leader John Wilkinson.
Scientists hope that by strengthening the monitoring of pharmaceuticals in the environment, they can develop strategies to limit the negative effects caused by the presence of these substances in nature.
