Are we medicating our fish?

By March 20, 2013Ocean News

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Don’t flush your medications down the toilet! Please, don’t do it! Even when the box or the information pamflet says that you can do it, avoid it. Maybe they won’t be the most toxic thing in the world, but the problem is that they will be dissolved in the water, and they will persist. So their final destination is likely to be in fish muscle tissues.

Why? Because fish sequester toxic chemicals in their muscle tissues. This makes a little dilution potentially dangerous. And we are only starting to know their effects!

Years ago, researchers from Umeå University found in the river Fyris, in Uppsala, a medication called oxazepam. This is a psychoactive, used as a treatment of anxiety and insomnia, for example. The concentration was unusually high, 0.58µg/l, but the scientists said that it’s comparable to other European rivers.

The researchers designed an experiment to prove the effects of this drug on perch. This is not new, but they used more realistic concentrations than the studies done before, so their results can really be used to understand the effects of pharmaceuticals in our rivers, and finally in our ocean.

The team raised juvenile perch in three different conditions: a drug-free control, one with twice the level of oxazepam found in Uppsala and another one with 500 times that level. The drugged perch stopped schooling (a common behaviour necessary for survival), and the ones with the highest concentration started to act like “risk takers”, losing their inhibitions and their fear about new environments, which make them vulnerable to predation. All the drugged fish were more efficient feeders, taking bigger preys at a higher rate. The final conclusions were: drugs change fish behavior.

Now we have a problem: there’s is no law to control behavioral effects of pollutants. Because, as I said before, you can flush some medicines legally, as they are not considered toxic pollutants, but what if they are able to modify animals behavior? Do we know enough to be sure that we are not harming the environment by flushing them?

You have loads of options to discard the medicines you won’t use anymore! Ask your pharmacist about a take-back program, or look for an NGO close to you, because usually they will be glad to donate your medicines to the disadvantaged! And don’t forget to check your first-aid kit more often!

After reading this article, does it make you think of all the drugs that could be in our ocean and aquatics environments and their affects on species behaviours and physiology?

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