We thought of relatively harmless drugs once assimilated by our body and that the residues evacuated in our toilets were marginal. However, they do not disappear completely after leaving our body. Some, particularly tough, are not entirely eliminated by wastewater treatment systems and can unexpectedly affect the marine environment, reports the Australian online media Sciencealer.
Published on April 10 in the journal Science, a new Swedish study reveals that certain drugs directly influence the behavior of animals, even in their migratory instinct. Often prescribed, Clobazam is a substance used in several anxiolytics and sleeping pills. He persists in wastewater, being released by patients who consume it, as well as in industrial effluents. The research team has observed its impact on young Atlantic salmon (Salmo Salar) Migration to the Baltic Sea. Surprisingly, they make the trip faster and better bypass obstacles.
To assess the effects of these molecules found in all the waters of the globe, the researchers first tested salmon in the laboratory, then studied the consequences on their behavior by carrying out an experience on free specimens.
Thanks to a system of implants diffusing the medication and follow -up tags attached to Atlantic salmon, scientists found that exposed fish reached the sea more often than those not treated. They also crossed the dams faster, responsible for migratory blockages.
In the laboratory, these fish also showed a change in their social behavior in the presence of a predator. These observations raise questions about the lasting effects of these substances on aquatic ecosystems.
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If the Clobazam seems to promote the migration of salmon, these disturbances are not without risk. Indeed, a change in trajectories or the migration calendar can expose fish to predators or environmental conditions that are not conducive to their survival.
The study underlines another alarming fact: the receptors targeted by our drugs are often present in animals. Thus, nearly 1,000 active pharmaceutical substances have already been detected in aquatic environments around the world, including in Antarctica.
To remedy this situation, scientists call to rethink wastewater treatment, modernizing stations. Reducing pharmaceutical pollution will mainly go through the development of more easily biodegradable drugs.
