American Association for the Advancement of Science

Something fishy going on... Antidepressants contaminating rivers make perch antisocial

 

Science Editor, Boston

Drugs used to treat anxiety and depression are contaminating rivers and streams where they are building up in concentrations that can affect the behaviour of wild freshwater fish, scientists have found.

Significant amounts of a benzodiazepine drug called Oxazepam, which is widely used to treat anxiety, are being flushed into rivers from sewage works. The concentrations are too low to be considered a health risk to humans but a study has shown they can still affect fish.

Benzodiazepines, such as Valium, are one of the most widely prescribed groups of drugs. They can be excreted from the body intact and persist in the treated effluent water released from sewage works into rivers, scientists said.

A study carried out in Sweden found that the relatively low concentrations of benzodiazepines commonly found in rivers throughout Europe, including Britain, can significantly affect the behaviour of the European perch.

The scientists found that perch exposed to extremely small concentrations of Oxazepam, as low as a fraction of a microgram per litre of water, were less sociable, bolder and ate faster than fish that were not exposed to the drug.

The scientists believe the subtle behavioral changes seen under experimental conditions indicate how the wider freshwater ecology could be affected by this kind of hidden environmental pollution.

They said that pharmaceutical compounds released into the aquatic environment might pose a greater problem than hitherto realised and that more should be done to degrade the chemicals before being released in the treated effluent water from sewage works.

“The solution to this problem isn't to stop medicating people who are ill but to try to develop sewage-treatment plants that can capture environmentally hazardous drugs,” said Jerker Fick of Umeå University in Sweden, who was part of the team.

“These drugs are not toxic or harmful in small doses, and are used to treat patients for therapeutic reasons. So there has not been that much research into what it does when it gets into our waterways,” Dr Fick said.

A survey of the River Fyris in Sweden, which receives wastewater effluent from the city of Uppsala, found concentrations of oxazepam of around 0.58 micrograms per litre. “These concentrations are comparable to hose of benzodiazepines reported in other European and American waters,” the scientists report in the journal Science.

It was one of 21 pharmaceuticals found in the water sampled by the researchers that have a similar effect to Oxazepam, the scientists said.

Tomas Brodin of Umea, the lead author of the study, told the American Association for the Advancement of Science meeting in Boston that when wild perch were exposed to similar concentrations they exhibited subtle but distinct changes to their natural behaviour.

“Perch that were exposed to Oxazepam lost interest in hanging out with the group, and some even stayed as far away from the group as possible,” Dr  Brodin said.

“While alone, fish that were exposed to Oxazepam dared to leave safe refuge and enter novel, potentially dangerous areas. In contrast, unexposed fish stayed hidden in their refuge. The exposed fish seemed much less stressed and scared, behaving calmer and bolder,” he said.

Fish exposed to the drug ate faster than non-exposed fish. This could affect the wider ecology because more voracious perch would eat more of the zooplankton that might otherwise prevent algal blooms, Dr Fick said.

'We found distinct behavioural changes in the perch, even at low levels of exposure. The changes can be seen as both beneficial or detrimental depending on the ecology,“ he said.

”The fish became bolder and fed faster, which is a good thing if there are no predators around, but could be risky if there are,“ be added.

”It could also have a knock-on effect on the surrounding environment. If the fish eat more zooplankton, then there is less in the water. Zooplankton eat algae, so without them there could be algae blooms.“

News
Shoppers at Selfridges department store in central London
news

News
Jeremy Paxman has admitted he is a 'one-nation Tory' and complained that Newsnight is made by idealistic '13-year-olds' who foolishly think they can 'change the world'.
peopleFormer Newsnight presenter is being touted for a brand new role
News
Michael Buerk in the I'm A Celebrity jungle 2014
people
Voices
File: David Cameron offers a toast during a State Dinner in his honour March 14, 2012
voicesAnd nobody from Ukip said babies born to migrants should be classed as migrants, says Nigel Farage
PROMOTED VIDEO
Arts and Entertainment
Avatar grossed $2.8bn at the box office after its release in 2009
filmJames Cameron is excited
Arts and Entertainment
Stik on the crane as he completed the mural
art
News
Happy in his hat: Pharrell Williams
people
Arts and Entertainment
Stella Gibson is getting closer to catching her killer
tvReview: It's gripping edge-of-the-seat drama, so a curveball can be forgiven at such a late stage
News
Brazilian football legend Pele pictured in 2011
peopleFans had feared the worst when it was announced the Brazil legand was in a 'special care' unit
News
i100(More than you think)
Sport
Brendan Rodgers seems more stressed than ever before as Liverpool manager
FOOTBALLI like Rodgers as a manager but Liverpool seem to be going backwards not forwards this season
News
ebooksNow available in paperback
News
The Magna Carta
archaeologyContemporary account of historic signing discovered
News
Phyllis Dorothy James on stage during a reading of her book 'Death Comes to Pemberley' last year
peopleJohn Walsh pays tribute to PD James, who died today
Sport
Benjamin Stambouli celebrates his goal for Tottenham last night
FOOTBALL
Life and Style
Dishing it out: the head chef in ‘Ratatouille’
food + drinkShould UK restaurants follow suit?
News
peopleExclusive: Maryum and Hana Ali share their stories of the family man behind the boxing gloves
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Ashdown Group: Senior PHP Developer - OOP, Javascript, HTML, CSS, SQL

£39000 per annum: Ashdown Group: Senior PHP Developer - OOP, Javascript, HTML,...

Austen Lloyd: Commercial / Residential Property - Surrey

Excellent Salary: Austen Lloyd: SURREY MARKET TOWN - SENIOR PROPERTY SOLICITOR...

Recruitment Genius: Graduate Programme - Online Location Services Business

Negotiable: Recruitment Genius: What do you want to do with your career? Do yo...

Recruitment Genius: Senior QC Scientist

Negotiable: Recruitment Genius: This company is a leading expert in immunoassa...

Day In a Page

Homeless Veterans Christmas Appeal: ‘We give them hope. They come to us when no one else can help’

Christmas Appeal

Meet the charity giving homeless veterans hope – and who they turn to when no one else can help
Should doctors and patients learn to plan humane, happier endings rather than trying to prolong life?

Is it always right to try to prolong life?

Most of us would prefer to die in our own beds, with our families beside us. But, as a GP, Margaret McCartney sees too many end their days in a medicalised battle
Thomas Cook's outgoing boss Harriet Green got by on four hours sleep a night - is that what it takes for women to get to the top?

What does it take for women to get to the top?

Thomas Cook's outgoing boss Harriet Green got by on four hours sleep a night and told women they had to do more if they wanted to get on
Christmas jumper craze: Inside the UK factory behind this year's multicultural must-have

Knitting pretty: British Christmas Jumpers

Simmy Richman visits Jack Masters, the company behind this year's multicultural must-have
French chefs have launched a campaign to end violence in kitchens - should British restaurants follow suit?

French chefs campaign against bullying

A group of top chefs signed a manifesto against violence in kitchens following the sacking of a chef at a Paris restaurant for scalding his kitchen assistant with a white-hot spoon
Radio 4 to broadcast 10-hour War and Peace on New Year's Day as Controller warns of cuts

Just what you need on a New Year hangover...

Radio 4 to broadcast 10-hour adaptation of War and Peace on first day of 2015
Cuba set to stage its first US musical in 50 years

Cuba to stage first US musical in 50 years

Claire Allfree finds out if the new production of Rent will hit the right note in Havana
Christmas 2014: 10 best educational toys

Learn and play: 10 best educational toys

Of course you want them to have fun, but even better if they can learn at the same time
Paul Scholes column: I like Brendan Rodgers as a manager but Liverpool seem to be going backwards not forwards this season

Paul Scholes column

I like Brendan Rodgers as a manager but Liverpool seem to be going backwards not forwards this season
Lewis Moody column: Stuart Lancaster has made all the right calls – now England must deliver

Lewis Moody: Lancaster has made all the right calls – now England must deliver

So what must the red-rose do differently? They have to take the points on offer 
Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

It's in all our interests to look after servicemen and women who fall on hard times, say party leaders
Millionaire Sol Campbell wades into wealthy backlash against Labour's mansion tax

Sol Campbell cries foul at Labour's mansion tax

The former England defender joins Myleene Klass, Griff Rhys Jones and Melvyn Bragg in criticising proposals
Nicolas Sarkozy returns: The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?

Sarkozy returns

The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?
Is the criticism of Ed Miliband a coded form of anti-Semitism?

Is the criticism of Miliband anti-Semitic?

Attacks on the Labour leader have coalesced around a sense that he is different, weird, a man apart. But is the criticism more sinister?
Ouija boards are the must-have gift this Christmas, fuelled by a schlock horror film

Ouija boards are the must-have festive gift

Simon Usborne explores the appeal - and mysteries - of a century-old parlour game