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article imagePharmaceutical waste puts fish at risk

By Tim Sandle     Mar 3, 2013 in Environment
A new study has looked at the affects of pharmaceutical by-products that enter the water supply and how some by-products can affect the behavior of fish, putting them at risk.
Earlier the Digital Journal highlighted the risks that the by-products of pharmaceuticals pose, to fresh water, if they are not eliminated through sewage treatment plants. Now, a new study shows empirically the effects that some pharmaceutical compounds can have on fish. As well as the by-products from people excreting, too many unwanted pills are flushed down the toilet.
Specifically, the study looks at anti-anxiety medications. Toxicologists have long held concerns that psychiatric drugs, which target brain molecules, could affect many different types of animals.
The new study looked at oxazepam, a type of benzodiazepine. For the research, the Independent summarizes, scientists measured concentrations of oxazepam in a Swedish river, five meters downstream of a wastewater treatment plant. The level of oxazepam was 0.58 micrograms per liter. European perch (Perca fluviatilis) that they collected from the river had six times that concentration stored in their muscles, an average of 3.6 micrograms per kilogram.
The results showed that perch living in water spiked with such drug became bolder, less social and more active than unexposed fish. They also ate much more quickly.
In parallel, Science Devil notes, research was carried out in a laboratory.Here the researchers placed young perch in tanks for seven days with either no oxazepam or with the drug at one of two concentrations: 1.8 micrograms per liter or 910 micrograms per liter. Later dissections showed that fish exposed to the lower drug level accumulated amounts of oxazepam in their muscles similar to the wild perch’s supply.
The main concern is that these behavioral changes disrupt the food chain. This is because fish living in wastewater-polluted rivers become more vulnerable to predators, not least from behaving in ways that attract predators or swimming into areas that they otherwise would have avoided.
The study was led by Tomas Brodin of Sweden’s Umeå University and the findings were published in the journal Science.
More about Pharmaceuticals, Fish, waste products, Fresh water, Predators
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