Freshwater fish are in danger of becoming addicted to methamphetamine, Czech scientists have warned in a study published in the prestigious Journal of Experimental Biology. Their research has shown that after spending time in meth contaminated waters, fish became less active and displayed withdrawal symptoms.
The Czech Republic has long been known as the biggest producer of illegal crystal meth, known as Pervitin, in Europe. Researchers from the University of Life Sciences have now found that the drug, which enters the waterways through discharge from wastewater plants, can also have a devastating effect on fish. Researchers performed lab experiments with brown trout, isolating them in a water tank laced with one microgram of methamphetamine. After spending two months in the meth contaminated water, the fish became less active, but they also displayed drug withdrawal symptoms, says behavioural ecologist Pavel Horký, who headed the research team: “Once we denied the fish access to the methamphetamine, they were trying to seek its source. At the same time, their activity ceased and their behaviour changes were accompanied by changes in the brain tissues, stemming from residues of amphetamine in the brain.”
Mr. Horký says that while the level of meth they used was not insignificant, similar concentrations have previously been found in freshwater streams in the Czech Republic.
“It is still an environmentally relevant concentration. The concentrations can actually range between hundreds of nanograms to units of micrograms.
“They change throughout the year, but also during the week. With many people using the drugs recreationally, you can see a significant increase at weekends.”
Methamphetamine is considered one of the most serious global health threats, with its consumption significantly increasing in recent years. The Czech study shows that the problem does not concern only humans but can also threaten aquatic ecosystems:
“It is a big warning, because the animals can start to behave unnaturally. Their desire for drugs may override their desire to obtain a suitable reproductive partner, a food source, to hide from the harsh environment or from predators. From this point of view, the effect of the drug can be as devastating as the effect it has on people and human society.”
Fish that live near wastewater treatment plants are exposed not only to methamphetamines, but also to dozens to hundreds of other chemicals, including antidepressants, common painkillers, caffeine and substances used in veterinary medicine. Previous studies have shown that hormones from contraceptives, for example, can change the sex of fish.
The European Union has been trying to ensure that wastewater treatment in its member countries improves, but according to researcher Pavel Horký it is not that easy, both technologically and financially. One of the most effective ways to reduce water contamination, he says, is to stop overusing pharmaceuticals.