Prozac in the water makes shrimp go crazy
July 21, 2010
A British scientist has found that anti-depressants in water cause shrimp to behave more recklessly than usual.
The study, published in the journal Aquatic Toxicology, found that shrimp behaviour changed when exposed to the same levels of Prozac found in the waste water that flows to rivers and estuaries because of the drugs humans excrete in their sewage.
For many years, scientists have known that drugs in the water have had an impact on marine life. For example, estrogen in the water has caused what Dr. Alex Ford calls “the feminization” of fish.
That got Ford and another researcher thinking that perhaps all kinds of drugs were potentially affecting marine life.
So in his laboratory at the University of Portsmouth’s Institute of Marine Sciences, Ford decided to test the impact of Prozac, or fluoxetine, on shrimp.
The study, conducted by Ford and Yasmin Guler, found that shrimp, when exposed in the laboratory to the same level of Prozac as in the waste water of rivers, behaved totally differently than they usually do.
Shrimp usually gravitate toward safe, dark regions. But when exposed to Prozac in the laboratory they were five times more likely to swim toward a bright region of water, which would leave them vulnerable to a predator, said Ford.
In the wild, these shrimp often fall prey to a parasite that affects their serotonin levels. In those cases the shrimp with the parasite swim to the light areas or open areas of the water and they are eaten by fish or other predators. Studies have shown that the likelihood of the shrimp being eaten by predators increased ten to 20 times, Ford said.
“We wondered if we exposed these shrimp (in the lab) to antidepressants whether the serotonin levels would change and make them swim to the light in the same way as the parasite does.”
It seems they did, according to Ford’s study. While he can’t be 100 per cent sure about how wild shrimp would behave if exposed to Prozac residue in waste treatment water, it’s a good bet their behaviour would be much the same.
Even more troubling is the fact that serotonin levels effect other biological functions in shrimp, he said. “It also controls lots of other biological functions including reproduction and maturation.”
There are many other drugs in the world’s water supply.
The long term implications are unknown, Ford said