Drugs flushed into the environment could be cause of wildlife decline

pharmaceuticals flushed into the environment via human and animal sewage could be a hidden cause of the global wildlife crisis, according to new research. The scientists warn that worldwide use of the drugs, which are designed to be biologically active at low concentrations, is rising rapidly but that too little is currently known about their effect on the natural world.

Studies of the effect of pharmaceutical contamination on wildlife are rare but new work published on Monday reveals that an anti-depressant reduces feeding in starlings and that a contraceptive drug slashes fish populations in lakes.

“With thousands of pharmaceuticals in use globally, they have the potential to have potent effects on wildlife and ecosystems,” said Kathryn Arnold, at the University of York, who edited a special issue of the journal Philosophical Transactions of the Royal Society B. ”Given the many benefits of pharmaceuticals, there is a need for science to deliver better estimates of the environmental risks they pose.”

She said: “Given that populations of many species living in human-altered landscapes are declining for reasons that cannot be fully explained, we believe that it is time to explore emerging challenges,” such as pharmaceutical pollution.

Research published in September revealed half of the planet’s wild animals had been wiped out in the last 40 years. In freshwater habitats, where drug residues are most commonly found, the research found 75% of fish and amphibians had been lost.

A few dramatic examples of wildlife harmed by drug contamination have been discovered previously, including male fish being feminised by the synthetic hormones used in birth-control pills and vultures in India being virtually wiped out by an anti-inflammatory drug given to the cattle on whose carcasses they feed. Inter-sex frogs have also recently been found in urban ponds contaminated with wastewater.