Animal Pharm: Drugs in Wastewater May Be Affecting Fish

Fish on Anti-anxiety drugs become more aggressive

Anti-anxiety drugs induce abnormal behaviour in Perch. Photo Credit: USDA

Science published a report this week, detailing the impacts of human anti-anxiety drugs on fish. Why would anyone deliberately give a psychiatric drug to a fish, you may ask? Well, it helps us to understand what happens to the fish when we accidentally give it to them. It turns out that the drug in question, Oxazepam, passes through our bodies intact, survives wastewater treatment, and ends up in aquatic ecosystems downstream of wastewater treatment plants.

Pharmaceutical pollution isn’t a new phenomenon, but relatively little is known about the ecological impact of such occurrences. This study has shown that Oxazepam induces marked behavioural responses in wild European perch. Following exposure to the drug the perch became more active, increased their feeding rate and became less social (choosing to swim alone rather than forming shoals).

While concentrations used in the study are comparable to measured in-field concentrations, further research is needed before we can categorically state that the effects observed in this study are occurring outside the lab. Additionally, we can only speculate as to how these behavioural changes will impact fish populations and the habitats they reside in. The impact on shoaling behaviour, for example, could easily prove problematic. Shoaling provides fish with anti-predatory and reproductive benefits, so interfering with this behaviour could potentially alter reproductive rates and increase a fish’s susceptibility to predation.

This story gained a respectable amount of media attention this week, though unfortunately in some cases it was reported as a humorous curiosity, detracting from the potentially serious implications of the study. I can appreciate that the idea of a drugged up fish getting the munchies is a comical image, but it is a misleading distortion of the rather disturbing truth. The issue of pharmaceutical pollution doesn’t end with the unintended ecological consequences. This kind of pollution could potentially be affecting humans as well.

Gree frog switching Sex

The Frog Prince is turning into the Frog Princess.

You may have heard of the phenomenon of male frogs in suburban ponds developing eggs in their testes. Researchers at Yale, suspect that these abnormalities are caused by exposure to synthetic oestrogens, such as those found in birth control pills and some prostate cancer medications. On top of triggering bizarre abnormalities in frogs, synthetic oestrogen pollution could prove damaging to human health. As endocrine disruptors, these substances can induce reproductive, neurological and immune system abnormalities by interfering with the body’s hormonal system. I should point out that while the synthetic oestrogens affecting suburban frogs are likely to be from birth control pills, most of the oestrogen contamination found in our drinking water is from other sources.

I realise that this is all a bit depressing, and you may have come here with the hope of reading about animals “tripping balls”.

Stoned Dog

Dude. I’m totally licking bal…I mean tripping balls. Credit:Nathan Laurell

Well, you’ve been very good and stuck with me through the depressing part so as a thank you, here are some examples of just that:

  • In 1962, researchers from the University of Oklahoma decided to give LSD to an elephant to determine if it could induce a state of temporary madness known as musth. Instead they managed to induce a state, of a rather more permanent condition, known as death. At 297 mg, it is the highest dose of LSD ever administered to a living creature (to put that number in context, it’s about 3,000 times the typical human dosage). Some years later, a similar experiment was undertaken but instead of injecting the LSD as the previous researchers had done, the LSD was introduced to the animals via their drinking water. This time around, the animals didn’t experience any apparent ill effects. After just a few hours of lethargic movement and unusual vocalisations, the elephants resumed normal behaviour.
  • Reindeer regularly consume the fly agaric mushroom (Amanita muscaria). In humans, this mushroom is psychoactive and many believe the reindeer are also enjoying the psychoactive properties. At the very least, they’re very fond of the mushrooms, and the reindeer-herding Saami people of Lapland often use them to attract their semi-wild livestock.
  • Breaking-Baaaad! Methamphetamine abuse is rising globally and since law enforcement officers may have to subdue intoxicated individuals via non-lethal methods such as tasering, it is vital that we ensure that the combination of meth and electricity is indeed “non-lethal”. The good people of Taser International decided to offer us that reassurance by dosing twelve sheep with methamphetamine hydrochloride… and then tasering them.
  • Over the years, spiders have been exposed to more drugs than Hunter S. Thompson. NASA (and others) have given spiders a myriad of drugs to see how they affect web spinning. The results aren’t all that shocking, with the possible exception of LSD which led to the production of highly ordered webs. Check out the image below to see how each drug affected their ability to spin a decent web.
Spiders spin strange webs under the influence of drugs

I was gonna spin a web – but then I got high…Credit: NASA

Ok, we’ve had our fun with drugs (figuratively) but I need to take this opportunity to remind you to “Just Say No”. Or whatever, I’m not your boss. I don’t really care what you do.


Brodin et al. 2013 “Dilute Concentrations of a Psychiatric Drug Alter Behaviour of Fish From Natural Populations“.

“Elephants on Acid and Other Bizarre Experiments” by Alex Boese

“Collins Mushroom Miscellany” by Patrick Harding


Credit is as per caption.

Nathan Laurell’s Flickr Stream


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