Could Prozac be killing off our starlings?

Prozac and other antidepressants in the water system could be the reason we're seeing fewer starlings in our skies, according to a study by a York ecologist.

The research led by Dr Kathryn Arnold, from our Department of Environment and Geography, found that starlings that ate Prozac-laced worms suffered the same side effects experienced by humans - a loss of libido and appetite.

Prozac-laced worms

With 50 million prescriptions written for anti-depressant drugs each year in the UK, traces of them are present in the water system. Worms, maggots and flies at sewage treatment plants have been found to contain these pharmaceuticals, which can then be eaten by wild birds.

Dr Arnold’s team measured the level of Prozac present in earthworms living in sewage. It was tiny, around three to five per cent of the average human dosage.

They then fed worms containing the same concentration of the drug to captive starlings and monitored their behaviour over six months.

Dr Arnold said: "The major findings were that the starlings lost their appetite and libido. Compared with the control birds that hadn’t had any Prozac, they ate much less and snacked throughout the day."

To test libido, female starlings were introduced to males.

"The control females were interacting with them but the females who’d been on Prozac – they sat in the middle of the cage not interested at all," said Dr Arnold.

Dr Arnold added: "Our research suggests that Prozac in the water system could lead to a decline in starlings breeding and if the birds are taking in fewer calories they are less likely to survive the winter – thus leading to a reduction in starling numbers."

Fish on drugs

And it’s not just birds that are affected by drugs in our water system.

Research led by Professor Alistair Boxall, also from our Department of Environment and Geography, suggests that many rivers contain levels of ibuprofen that could be adversely affecting fish health.

Using a new modelling approach, the researchers estimated the levels of 12 pharmaceutical compounds in rivers across the UK. They found that while most of the compounds were likely to cause only a low risk to aquatic life, ibuprofen might be having an adverse effect in nearly 50 per cent of the stretches of river studied.

Professor Boxall said: "While our study focused on pharmaceuticals, the approach we have developed could also be valuable in assessing the risks of other ‘down the drain’ chemicals and could help inform our understanding of the important dissipation processes for pharmaceuticals in the pathway from the patient to the environment."

Protecting wildlife

So what can be done to protect wildlife like starlings and fish from the effects of drugs?

Professor Boxall and PhD student, Tom Bean, together with scientists in our Centre of Excellence in Mass Spectrometry, think they may have found a solution.

They have spent six months working in partnership with PyroPure Ltd testing a new technology designed to destroy active pharmaceutical ingredients found in pharmaceutical waste.

Seventeen of the most thermally stable pharmaceuticals were tested in the trial, which revealed that PyroPure®technology destroys over 99 per cent of 10 of the pharmaceuticals and an average of 94 per cent of the remaining seven.

Professor Boxall said: "Our work demonstrates that the technology could help reduce the emissions of pharmaceuticals to the natural environment and have big benefits for ecosystem health. The system also provides a range of other environmental and economic benefits that could radically change how waste of this nature is collected and destroyed."

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Compared with the control birds they ate much less and were not interested in males.”

Dr Kathryn Arnold
Department of Environment and Geography
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Dr Kathryn Arnold

Dr Arnold is is a Royal Society Research Fellow working mainly on the behavioural and physiological responses of vertebrates to changes in the environment.

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