People use in their lives more and more chemicals. A significant part of these chemicals will eventually get into water environment where they influence organisms. Municipal wastewater is still an important source of contamination of water environment with wide spectrum of xenobiotic substances, mostly drug residues, detergents, disinfection and cosmetics, but also drugs which are abused in society.

Drugs, similar to, e. g. antidepressants or analgesics, influence nervous systems of individuals, who use them or who are unintentionally exposed to these substances. Very popular “Class A drug” in the Czech Republic is methamphetamine (“pervitin”), which is evidenced by its frequent presence in many monitored localities of our watercourses. The highest concentrations were found in places, where "treated" municipal wastewater flows. A team of scientists from the Department of Zoology and Fisheries of the Czech University of Agriculture in Prague and from the Faculty of Fisheries and Protection of Waters of the University of South Bohemia in České Budějovice decided to study the influence of methamphetamine using a laboratory experiment. The team proved that trout, which were exposed to methamphetamine for a long time started to show signs of addiction and withdrawal symptoms after removing of the source. Among other things, they were actively looking for a source of methamphetamine and they decreased their physical activity. These changes were accompanied by the presence of amphetamine (metabolite of methamphetamine) in brain and at the same time by changing its overall metabolome.

The results of this research also suggest possible ecological contexts. Frequent high occurrence of individuals under drains of wastewater treatment plants can be partially explained by rich presence of food, however, some substances present in the wastewater (e.g., studied methamphetamine) can act as attractants attracting fish to the source of pollution. Then, a cocktail of other substances present in a wastewater can significantly affect individuals in a contaminated locality. The presence of psychoactive substances in the aquatic environment may also be related to the loss of interest in food intake or the suppression of escape reactions from predators. In other words, drug dependence can have similarly negative effects on wildlife populations as on human society.

The original article was published in the science magazine Journal od Experimental Biology with the support of the Grant Agency of the Czech Republic (GAČR 20-09951S).

REFERENCES: Horký, P., Grabic, R., Grabicová, K., Brooks, B. W., Douda, K., Slavík, O., Hubená, P., Sancho Santos, E. M. and Randák, T. (2021). Methamphetamine pollution elicits addiction in wild fish. J. Exp. Biol. 224, jeb242145.

DOI: 10.1242/jeb.242971

WWTP effluents are still a significant source of contamination of the aquatic environment with foreign substances.

Brown trout.

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