Eels high. Rivers polluted with drugs

The presence of drugs and their metabolites in rivers is a new and growing environmental threat. It puts an already critically endangered species of European eel at risk.

Critically endangered European eels are exposed to cocaine, according to a study published in the „Science Of The Total Environment” By scientistow from the University of Naples.

The European eel inhabits the rivers and lakes of Western and Central Europe. Migrates to the ocean to breed, then follows it back inland. This cycle is repeating itself. Their numbers have declined sharply in recent decades. This is due to a combination of such factorsoin, such as toxic pollution, overfishing, parasites, climate change and dams.

To the mentioned factorow also need to add cocaine. Its level in rivers is admittedly low, but eels suffer irreversible physiological damage when they come into contact with the drug, whoore could threaten the future of the entire species.

In a 2009 study. They measured cocaine levels in Belgian rivers and wastewater treatment plantsow. It turned out that a liter of water can contain from 1 to 753 nanogramsoin this relationship. Glowny metabolite of cocaine – Benzoylgonine is found in water in values ranging from 1 to 2258 nanogramsow per liter. Scientists stress that a similar situation occurs roalso in other regions of Europe.

Scientists have already discovered that cocaine can accumulate in the eel’s body and affect its skohand and hormone levelsow. However, to assess the impact of cocaine in freshwater environments, Italian researchers studied 150 adult eels for this purpose.

Someore individuals were kept in tanks containing 20 nanograms ofoin cocaine per liter. Some of the individualoIn was kept, as a control group. The experiment lasted 50 days.

Experience has shown that eels kept in tanks of water with cocaine suffer severe skeletal muscle damage. The researchers also observed that the individuals became hyperactive. Not surprisingly, cocaine is a known stimulant.

Researchers have also discovered accumulations of the drug in mozgu, muscles, gills and other tissues of eels. There has also been a breakdown of muscle tissue, and irreversible muscle damage can make it difficult for eels to migrate, ktora is often thousands of kilometersow. Thus, eels may stop reproducing.

Photo. Science of the Total Environment

„Study shows that even low concentrations of cocaine in the environment cause serious damage to the morphology and physiology of eel skeletal muscles, confirming its harmful effects Potentially affecting the survival of this species” – wrote the authors in a publication.

The drugs end up in the wod through ineffective disposal in sewage treatment plantsow. Researchers estimate that only 50 percent is removed. drugow from water. This situation is not exclusive to Europe. Trace amounts of the drug can be found in rivers around the worldow. They can harm animals living in these environments. But this is not just about illegal drugs. Traces of antibiotics can be found in riversow, hormoneoin, steroidowhether the centraloin contraceptives.

Other studies have shown that contraceptives reduced fish populations in lakes and antidepressants caused starlings to stop feeding their offspring. Scientists point out to prevent entry of pharmaceuticalsow to wod, need to invest in infrastructure and improve treatment plants.

Sourceobackground: Science Alert, photo. CC BY-SA 3.0/ Wikimedia Commons/ Nevit Dilmen