In the latest study to demonstrate this disturbing connection, Portland State University researchers have found that Oregon shore crabs behave in very risky ways after being exposed to the antidepressant Prozac. This and other medications end up in the water after being flushed from toilets in homes and medical facilities and passing through the sewage system.
To gain insight into the effects of the drug on sea life, the researchers exposed the crabs to trace amounts of fluoxetine, which is the active ingredient found in Prozac. They kept them in tanks over a period of nine weeks, feeding them regularly and providing them with pebbles and sand for burrowing. They then conducted trials, with predators and without them, at day and night in order to study their behavior.
Under normal circumstances, Oregon shore crabs tend to forage at night, eating a diet that consist mostly of algae, carrion, and any other meat they happen to find. They spend most of their time near or underneath rocks found in fine sediment substrate and gravel. They burrow quickly into the sediment or hide under rocks and camouflage themselves while remaining very still to escape predators.
The researchers found that following exposure to fluoxetine, the crabs increased their foraging behavior. The amount of concern that they normally show for predators dropped dramatically, and they even started foraging during the daytime, which is a time they typically hide.
On top of that, they started fighting more with their fellow crabs from the same species, sometimes resulting in them killing or being killed by their foe. Their findings were published in the Ecology and Evolution journal.
The seawater near places inhabited by humans has long shown trace amounts of heavy metals from pesticides as well as caffeine and prescription drugs. Such contaminants affect the behavior of the animals living in the water in unpredictable ways, often changing their migration patterns and habitat preferences or spurring negative interactions.
Another recent study discovered high concentrations of antidepressants in Niagara River fish, including four types of bass, two types of perch, and several other species.
A 2010 study found that shrimp who were exposed to fluoxetine were a staggering five times more likely to swim toward light than away from it, which makes them more likely to be eaten by birds or fish. Over time, this could have a big impact on the shrimp population, which would throw off the entire ecosystem’s natural balance. The levels they were exposed to in the study mimicked those seen in actual waste water flowing in estuaries and rivers.
This issue is only likely to get worse as the number of Americans who take antidepressants continues to climb and wastewater facilities struggle to stay on top of it. Most are chiefly concerned with killing bacteria rather than removing antidepressants.
If you think this problem doesn’t really affect you, here’s some food for thought: Not only are these antidepressants getting into the bodies of marine life, but they could be making their way to your plate as well if you eat these fish, crabs and shrimp.
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