Posted by: Prospector PJ17 APR 2013
Environmental pollution by pharmaceuticals is increasingly recognised as a major threat to aquatic ecosystems worldwide. “Intersex” fish, displaying both male and female characteristics, are found in rivers across Europe. In 2004, the UK Environment Agency found that 86 per cent of male fish sampled at 51 UK sites also displayed female sexual characteristics. This is blamed on endocrine-disrupting chemicals, particularly ethinylestradiol from oral contraceptives.
And Swedish scientists have shown that oxazepam, which has been found to be accumulating in freshwater fish, makes the fish less sociable, eat more and become more adventurous. In a study published in Science (2013;339:814), the scientists concluded that this and similar drugs entering waterways could have unexpected ecological impacts on fish populations.
In their laboratory the Swedish researchers replicated concentrations of oxazepam found in the wild — 1.8?g per litre of water — and observed the altered behaviour of wild European perch. They found the drug had a similar effect to that seen in humans, reducing fear.
The Environment Committee of the European Parliament voted in November 2012 against proposals to tackle freshwater pollution from pharmaceuticals on the grounds of cost. The European Commission had proposed that concentrations of ethinylestradiol and diclofenac in surface waters should be limited. Diclofenac disrupts cell function in the liver, kidneys and gills of fish. The UK Government estimated that upgrading water treatment plants would cost up to £30bn. The proposals would have added 15 new chemicals to the current list of 33 substances that need tackling most urgently.
Evidence for fish feminisation caused by endocrine-disrupting chemicals is extensive and alarming, says Sergey Moroz, water policy officer for the World Wildlife Fund: “Unfortunately the problem is not going to go away and will only get worse and more difficult to solve.”