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A new study has shown that pharmaceutical drugs polluting the world’s waterways may significantly change the behavior of wild fish. A study of wild perch found that the presence of a widely prescribed anti-anxiety medication called oxazepam makes the fish more mellow but also more antisocial and vulnerable to predators—which could have a notable ecological impact.
All kinds of drugs regularly get into the water supply when people flush unneeded medication down toilets or pass trace amount in urine. Previous studies have demonstrated that pharmaceuticals typically found in the water supply can alter a fish’s behavior as well as its ability to reproduce. This new investigation by researchers at Umea University in Sweden was the first one to study environmental impact of a benzodiazepine. Also, it was the first to demonstrate behavioral changes in aquatic creatures from concentrations of pharmaceuticals close to those found in nature.
The researchers collected wild European perch from a pristine lake in Sweden. They exposed one group of perch to 1.8 µg/L of a benzodiazepine, oxazepam, for seven days. According to the researchers, this level of drug resulted in the fish having a muscle tissue concentration of oxazepam similar to that found in perch living in a river fed by Swedish wastewater treatment facilities. The fish that swam in water saturated with oxazepam became more active, less sociable and ate at a significantly faster rate.
Via LA Times
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