Are PCB's responsible for decline in Bottlenose dolphins?
August 2011. Many people have been thrilled at the sight of playful, energetic bottlenose dolphins around our coasts. But they may be surprised to hear that numbers of the local population around Cornwall are gradually declining. Conservationists are concerned that eventually we may lose them altogether. The reason for the drop in numbers has been a mystery until now, as local scientists think they know why.
Strandings
Over a period of six years, volunteers of Cornwall Wildlife Trust's Marine Strandings Network have collected bodies of stranded bottlenose dolphins washed ashore. They then take them to the pathologists at the Animal Health and Veterinary Laboratories Agency (AHVLA) at Polwhele in Truro to be examined. Having researched the decline in the population over a number of years, the Marine Strandings Network was keen to know why they died and wanted to find out more. Could there be a reason why, despite sightings of calves and young dolphins, the pod didn't appear to be thriving?
Post mortem
The dolphins were post mortemed by local veterinary pathologists at AHVLA Polwhele, as part of the UK Cetacean Strandings Investigation Programme, which is funded by Defra. Samples were tested for various diseases by Nick Davison, a scientist at the AHVLA.
Nick explains "Dolphins carry lots of diseases and can live for years with some of them without being adversely affected. However, there are certain bacteria that some of them carry that can severely compromise their health and may lead ultimately to their death. One of these is a bacterium called Brucella ceti, which affects many different species of cetaceans all over the world. Even healthy looking animals can carry the disease."
Brucella ceti
"We ran a wide range of routine tests on the samples we had stored from all eight of the bottlenose dolphins, including the test for Brucella ceti. What really surprised us was that half of the bottlenose dolphins we tested carried Brucella, which is a rare thing to find in this species and in this region. In fact, no other isolations of Brucella species were found in 15 bottlenose dolphins from the rest of England and Wales between 1989 and 2008, and only one out of 36 dolphins examined in
Scotland during the same period. We also discovered that the levels of Brucella in the Cornwall dolphins were much higher than in the other species we'd examined."
PCBs
The second shock for the researchers was the very high levels of polychlorinated biphenyls (known as PCBs) in the blubber of two of the dolphins. One of them had the highest level of PCBs recorded in this species in the UK in the last 20 years.
PCBs are toxic chemicals that used to be added to paints and cements, fire retardants, adhesives and hydraulic fluids. Because of their toxicity, they were banned about 20 years ago, but they still persist in the marine environment, particularly in coastal waters. They get into the fish the dolphins eat and are readily absorbed into fat, so the dolphins' blubber is an ideal reservoir.
High exposure to PCBs may increase susceptibility of the bottlenose dolphins to infections, including Brucella ceti. PCBs have also been linked to fertility and reproductive issues in dolphins and can affect the immune system, exposing the dolphins to a number of serious diseases and conditions such as meningitis swelling of the brain.
Scientists now think that chemical pollutants such as PCBs may be one of the possible causes of the decline of the local bottlenose dolphins.
Jan Loveridge, Coordinator of the Strandings Network says,"Strandings and sightings data suggest that UK bottlenose dolphin populations, including ours in Cornwall, have declined markedly from historic levels and the loss of any individuals from such a small population will have a strong impact on its ability to survive. We're so fortunate to have this local laboratory to help us find out what's killing our dolphins."
"The bottlenoses are such a local icon; they're part of Cornwall's heritage and one of the reasons that people visit the county. It would be a tragedy if we lost those precious moments when we see them leap and flip in the air and I'd hate to think that our children and grandchildren might be denied that pleasure. We need to keep monitoring how they're doing, and do whatever we can to protect them. Research like this by Nick Davison is crucial if we're to understand what's going on in our marine environment."
Although Brucella can be passed to humans, the risk from dolphins is very small indeed. Nevertheless, the AHVLA recommends that people don't swim with dolphins or touch any bodies they find on the beach, just in case. Instead, they urge the public to call the Trust's Marine Strandings Network on 0845 201 2626 if they find a stranded dolphin.
The publication describing the findings of this research can be read on the Marine Strandings Network's website www.cwtstrandings.org/publications.htm.
http://www.wildlifeextra.com/go/news/dolphins-pcb.html
Showing posts with label water pollution. Show all posts
Showing posts with label water pollution. Show all posts
Monday, August 22, 2011
Wednesday, June 8, 2011
Thousands of River Thames fish killed by storm sewage
8 June 2011
Thousands of fish have died after large amounts of storm sewage flooded into the River Thames.
More than 450,000 tonnes of sewage overflowed into the river in west London when heavy rain fell on Sunday.
The Environment Agency said oxygen had been added along a 1km (0.6m) stretch of water where dead fish and sewage debris has been spotted.
Thames Water is carrying out a clear-up operation along a 12km (7.5m) stretch between Kew and Albert Bridge.
The Environment Agency said more than 250,000 tonnes of storm sewage from sewer overflows, and at least 200,000 tonnes of storm sewage from the Mogden sewage treatment works in Isleworth, was released into the river at the weekend.
Oxygenation vessels
This, combined with the current warm, dry weather and low river flows, resulted in low oxygen levels and fish deaths along a 1km stretch of the river.
Fish, including flounder, bream, roach, eel, dace and other aquatic life such as water shrimps, have been found dead.
Thames Water has put hydrogen peroxide into the water at three different locations, to add oxygen, and the agency has sent its oxygenation vessels to the area.
According to the agency's director, Howard Davidson, discharges from combined sewers happen 50 to 60 times a year and can be caused by as little as 2mm of rainfall.
Mr Davidson said that on Sunday, more than 30mm had fallen over west London.
He said: "This is a major sewage pollution incident which has caused the death of a huge number of fish.
"We are currently monitoring Thames Water's clean up efforts and assessing the full impact but unfortunately we may never know the exact numbers of fish that have died."
'Totally unsatisfactory'
Storm sewage is waste diluted with rainwater and occurs where a combined sewage network operates - one which takes both sewage from homes and businesses and rainfall run-off from roads and other hard surfaces.
Martin Baggs, from Thames Water, said: "Incidents like this are clearly totally unsatisfactory in a modern capital city and we have a major programme of work under way to sort the problem out."
Thames Water is currently reviewing responses to the first round of consultation on plans for a 20-mile (32km) "super-sewer".
The proposed Thames Tunnel would run from west to east London, broadly following the route of the river, collecting storm sewage.
If approved, construction on the tunnel would begin in 2013 and be completed by 2020.
http://www.bbc.co.uk/news/uk-england-london-13693265
Thousands of fish have died after large amounts of storm sewage flooded into the River Thames.
More than 450,000 tonnes of sewage overflowed into the river in west London when heavy rain fell on Sunday.
The Environment Agency said oxygen had been added along a 1km (0.6m) stretch of water where dead fish and sewage debris has been spotted.
Thames Water is carrying out a clear-up operation along a 12km (7.5m) stretch between Kew and Albert Bridge.
The Environment Agency said more than 250,000 tonnes of storm sewage from sewer overflows, and at least 200,000 tonnes of storm sewage from the Mogden sewage treatment works in Isleworth, was released into the river at the weekend.
Oxygenation vessels
This, combined with the current warm, dry weather and low river flows, resulted in low oxygen levels and fish deaths along a 1km stretch of the river.
Fish, including flounder, bream, roach, eel, dace and other aquatic life such as water shrimps, have been found dead.
Thames Water has put hydrogen peroxide into the water at three different locations, to add oxygen, and the agency has sent its oxygenation vessels to the area.
According to the agency's director, Howard Davidson, discharges from combined sewers happen 50 to 60 times a year and can be caused by as little as 2mm of rainfall.
Mr Davidson said that on Sunday, more than 30mm had fallen over west London.
He said: "This is a major sewage pollution incident which has caused the death of a huge number of fish.
"We are currently monitoring Thames Water's clean up efforts and assessing the full impact but unfortunately we may never know the exact numbers of fish that have died."
'Totally unsatisfactory'
Storm sewage is waste diluted with rainwater and occurs where a combined sewage network operates - one which takes both sewage from homes and businesses and rainfall run-off from roads and other hard surfaces.
Martin Baggs, from Thames Water, said: "Incidents like this are clearly totally unsatisfactory in a modern capital city and we have a major programme of work under way to sort the problem out."
Thames Water is currently reviewing responses to the first round of consultation on plans for a 20-mile (32km) "super-sewer".
The proposed Thames Tunnel would run from west to east London, broadly following the route of the river, collecting storm sewage.
If approved, construction on the tunnel would begin in 2013 and be completed by 2020.
http://www.bbc.co.uk/news/uk-england-london-13693265
Saturday, January 1, 2011
Freshwater wildlife thrives in cleanest rivers since Industrial Revolution
Otters, water voles and many species of freshwater fish make dramatic recovery as water quality continues to improve
Otters, water voles and species of freshwater fish which had all but vanished from waterways have made a dramatic recovery following the healthiest decade for rivers since the industrial revolution.
The toxic effects of pesticides nearly wiped out the wild otter in the 1970s, but steady improvements in water quality mean their numbers are expected to make a full recovery.
Otters may already have reached their maximum capacity in parts of the south-west of England, Cumbria and Northumbria. In the past 30 years, positive sightings have risen 10-fold, says a report by the Environment Agency.
The return of wildlife in and around the waterways reflects clean-up operations by water companies and environmental bodies to meet national and forthcoming European water quality directives.
The number of serious water pollution incidents has more than halved since 2001, while major conservation programmes have protected and restored rivers, streams and lakes.
Water voles are also returning to riverbanks after serious habitat degradation in the 1990s saw the mammal become critically endangered in Britain. According to the agency, water voles have recently been spotted in 30 locations.
Fish are also now thriving in once polluted rivers. The Tyne has seen record numbers of migrating salmon, while the Thames recorded its highest number of sea trout since many species were wiped out in parts of the river by pollution in the 1830s. The agency boosted fish populations with more than half a million farmed fish, including roach, barbell, tench, dace and chub.
Water quality tests on rivers in the Thames catchment area in 2008 found that 80% were "very good" or "good", compared with just 53% in 1990. Officials have recorded 125 fish species in the Thames estuary, which is home to shellfisheries and provides nursing grounds for sole and bass.
Ian Barker, the agency's head of water, said: "Rivers in England and Wales are at their healthiest for over a century, with otters, salmon and other wildlife returning in record numbers."
Water quality will need to improve more if environmental organisations are to tackle pollution that runs into waterways from fields and roads. A further 9,500 miles of rivers and streams are due to be revitalised by the agency over the next five years.
Ian Sample, science correspondent The Guardian,
http://www.guardian.co.uk/environment/2010/dec/31/freshwater-wildlife-thriving-clean-rivers
Otters, water voles and species of freshwater fish which had all but vanished from waterways have made a dramatic recovery following the healthiest decade for rivers since the industrial revolution.
The toxic effects of pesticides nearly wiped out the wild otter in the 1970s, but steady improvements in water quality mean their numbers are expected to make a full recovery.
Otters may already have reached their maximum capacity in parts of the south-west of England, Cumbria and Northumbria. In the past 30 years, positive sightings have risen 10-fold, says a report by the Environment Agency.
The return of wildlife in and around the waterways reflects clean-up operations by water companies and environmental bodies to meet national and forthcoming European water quality directives.
The number of serious water pollution incidents has more than halved since 2001, while major conservation programmes have protected and restored rivers, streams and lakes.
Water voles are also returning to riverbanks after serious habitat degradation in the 1990s saw the mammal become critically endangered in Britain. According to the agency, water voles have recently been spotted in 30 locations.
Fish are also now thriving in once polluted rivers. The Tyne has seen record numbers of migrating salmon, while the Thames recorded its highest number of sea trout since many species were wiped out in parts of the river by pollution in the 1830s. The agency boosted fish populations with more than half a million farmed fish, including roach, barbell, tench, dace and chub.
Water quality tests on rivers in the Thames catchment area in 2008 found that 80% were "very good" or "good", compared with just 53% in 1990. Officials have recorded 125 fish species in the Thames estuary, which is home to shellfisheries and provides nursing grounds for sole and bass.
Ian Barker, the agency's head of water, said: "Rivers in England and Wales are at their healthiest for over a century, with otters, salmon and other wildlife returning in record numbers."
Water quality will need to improve more if environmental organisations are to tackle pollution that runs into waterways from fields and roads. A further 9,500 miles of rivers and streams are due to be revitalised by the agency over the next five years.
Ian Sample, science correspondent The Guardian,
http://www.guardian.co.uk/environment/2010/dec/31/freshwater-wildlife-thriving-clean-rivers
Freshwater wildlife thrives in cleanest rivers since Industrial Revolution
Otters, water voles and many species of freshwater fish make dramatic recovery as water quality continues to improve
Otters, water voles and species of freshwater fish which had all but vanished from waterways have made a dramatic recovery following the healthiest decade for rivers since the industrial revolution.
The toxic effects of pesticides nearly wiped out the wild otter in the 1970s, but steady improvements in water quality mean their numbers are expected to make a full recovery.
Otters may already have reached their maximum capacity in parts of the south-west of England, Cumbria and Northumbria. In the past 30 years, positive sightings have risen 10-fold, says a report by the Environment Agency.
The return of wildlife in and around the waterways reflects clean-up operations by water companies and environmental bodies to meet national and forthcoming European water quality directives.
The number of serious water pollution incidents has more than halved since 2001, while major conservation programmes have protected and restored rivers, streams and lakes.
Water voles are also returning to riverbanks after serious habitat degradation in the 1990s saw the mammal become critically endangered in Britain. According to the agency, water voles have recently been spotted in 30 locations.
Fish are also now thriving in once polluted rivers. The Tyne has seen record numbers of migrating salmon, while the Thames recorded its highest number of sea trout since many species were wiped out in parts of the river by pollution in the 1830s. The agency boosted fish populations with more than half a million farmed fish, including roach, barbell, tench, dace and chub.
Water quality tests on rivers in the Thames catchment area in 2008 found that 80% were "very good" or "good", compared with just 53% in 1990. Officials have recorded 125 fish species in the Thames estuary, which is home to shellfisheries and provides nursing grounds for sole and bass.
Ian Barker, the agency's head of water, said: "Rivers in England and Wales are at their healthiest for over a century, with otters, salmon and other wildlife returning in record numbers."
Water quality will need to improve more if environmental organisations are to tackle pollution that runs into waterways from fields and roads. A further 9,500 miles of rivers and streams are due to be revitalised by the agency over the next five years.
Ian Sample, science correspondent The Guardian,
http://www.guardian.co.uk/environment/2010/dec/31/freshwater-wildlife-thriving-clean-rivers
Otters, water voles and species of freshwater fish which had all but vanished from waterways have made a dramatic recovery following the healthiest decade for rivers since the industrial revolution.
The toxic effects of pesticides nearly wiped out the wild otter in the 1970s, but steady improvements in water quality mean their numbers are expected to make a full recovery.
Otters may already have reached their maximum capacity in parts of the south-west of England, Cumbria and Northumbria. In the past 30 years, positive sightings have risen 10-fold, says a report by the Environment Agency.
The return of wildlife in and around the waterways reflects clean-up operations by water companies and environmental bodies to meet national and forthcoming European water quality directives.
The number of serious water pollution incidents has more than halved since 2001, while major conservation programmes have protected and restored rivers, streams and lakes.
Water voles are also returning to riverbanks after serious habitat degradation in the 1990s saw the mammal become critically endangered in Britain. According to the agency, water voles have recently been spotted in 30 locations.
Fish are also now thriving in once polluted rivers. The Tyne has seen record numbers of migrating salmon, while the Thames recorded its highest number of sea trout since many species were wiped out in parts of the river by pollution in the 1830s. The agency boosted fish populations with more than half a million farmed fish, including roach, barbell, tench, dace and chub.
Water quality tests on rivers in the Thames catchment area in 2008 found that 80% were "very good" or "good", compared with just 53% in 1990. Officials have recorded 125 fish species in the Thames estuary, which is home to shellfisheries and provides nursing grounds for sole and bass.
Ian Barker, the agency's head of water, said: "Rivers in England and Wales are at their healthiest for over a century, with otters, salmon and other wildlife returning in record numbers."
Water quality will need to improve more if environmental organisations are to tackle pollution that runs into waterways from fields and roads. A further 9,500 miles of rivers and streams are due to be revitalised by the agency over the next five years.
Ian Sample, science correspondent The Guardian,
http://www.guardian.co.uk/environment/2010/dec/31/freshwater-wildlife-thriving-clean-rivers
Monday, May 3, 2010
Water firms blamed for poisoned oysters
BRITAIN’S water companies have been accused of contaminating oysters and putting restaurant diners at risk by dumping raw sewage into rivers and the sea.
The number of people suffering food poisoning from raw oysters has risen dramatically, with 230 customers becoming ill in just a three-month period, according to new figures.
The Sunday Times revealed last week how six water companies have fought off an attempt by the Environment Agency to impose regulations on 4,200 overflow pipes that pump out raw sewage.
The scandal of contaminated oysters follows an outbreak of norovirus, which causes vomiting and diarrhoea, at Heston Blumenthal’s Fat Duck restaurant in Bray, Berkshire, last year. Chefs at Raymond Blanc’s Le Manoir aux Quat’ Saisons, which has two Michelin stars, were so concerned that they took oysters off the menu for almost a year.
Britain’s oyster industry is worth about £30m a year, with the main fisheries in the Thames estuary and on the Essex coast, in the Solent off the Isle of Wight and in the River Fal in Cornwall.
Producers fear their livelihoods are being jeopardised by food poisoning incidents linked to oysters. They point out that norovirus, which contaminates the oysters, originates in humans and so the source must be sewage being discharged into rivers and the sea.
“Some Third World countries use better technology than we do to treat sewage,” said David Jarrad, assistant director of the Shellfish Association of Great Britain. “We are as much the victims in this as the consumer.”
The Food Standards Agency has written to councils this year warning of an increase in suspected norovirus outbreaks linked to oysters. Its figures for December 2009 to February 2010 show that 32 restaurants and hotels were hit by outbreaks, with 230 people falling ill.
Norovirus is killed at high temperatures but oysters are typically eaten raw. In February last year Blumenthal was forced temporarily to close the Fat Duck, which has three Michelin stars, after 529 diners fell ill over a seven-week period. A Health Protection Agency report found sewage in oysters was most likely to blame. “Oysters harvested from sewage-contaminated waters will feed on the faecal residues,” it said.
Graham Larkin, operations manager at Colchester Oyster Fishery, which supplied the Fat Duck, said the vast majority of oysters were safe to eat but action needed to be taken.
“Fisheries are being affected by this all over the country. We want to see the water cleaned up,” Larkin said.
He now conducts rigorous tests for norovirus on oysters from the River Colne in Essex. Anglian Water has sewage treatment works on the river, which flows through Colchester, and overflow pipes which can discharge sewage during very wet weather.
Gary Jones, executive head chef at Blanc’s Le Manoir in Oxfordshire, said the restaurant now only served oysters that had been through a purification process and had been tested for norovirus. “We have to be confident that what we put on the menu is not going to harm anyone,” he said.
Jones said there was “not a shadow of a doubt” that oyster contamination was caused by sewage and the water companies should be held to account over discharges. “What we are doing to the seas is horrific. We should be taking this more seriously,” he said.
Water companies are allowed to dump raw sewage into rivers and the sea during wet weather to stop it backing up into homes, but oyster producers want to see more investment to limit the amount that is discharged.
Anglian Water said there was no proven link between its sewage discharges and contaminated oysters. Water UK, which represents water companies, said the industry had spent billions of pounds to improve the sewer system and as a result water quality in rivers and bathing areas had significantly improved.
Jon Ungoed-Thomas
http://www.timesonline.co.uk/tol/news/environment/article7114086.ece
The number of people suffering food poisoning from raw oysters has risen dramatically, with 230 customers becoming ill in just a three-month period, according to new figures.
The Sunday Times revealed last week how six water companies have fought off an attempt by the Environment Agency to impose regulations on 4,200 overflow pipes that pump out raw sewage.
The scandal of contaminated oysters follows an outbreak of norovirus, which causes vomiting and diarrhoea, at Heston Blumenthal’s Fat Duck restaurant in Bray, Berkshire, last year. Chefs at Raymond Blanc’s Le Manoir aux Quat’ Saisons, which has two Michelin stars, were so concerned that they took oysters off the menu for almost a year.
Britain’s oyster industry is worth about £30m a year, with the main fisheries in the Thames estuary and on the Essex coast, in the Solent off the Isle of Wight and in the River Fal in Cornwall.
Producers fear their livelihoods are being jeopardised by food poisoning incidents linked to oysters. They point out that norovirus, which contaminates the oysters, originates in humans and so the source must be sewage being discharged into rivers and the sea.
“Some Third World countries use better technology than we do to treat sewage,” said David Jarrad, assistant director of the Shellfish Association of Great Britain. “We are as much the victims in this as the consumer.”
The Food Standards Agency has written to councils this year warning of an increase in suspected norovirus outbreaks linked to oysters. Its figures for December 2009 to February 2010 show that 32 restaurants and hotels were hit by outbreaks, with 230 people falling ill.
Norovirus is killed at high temperatures but oysters are typically eaten raw. In February last year Blumenthal was forced temporarily to close the Fat Duck, which has three Michelin stars, after 529 diners fell ill over a seven-week period. A Health Protection Agency report found sewage in oysters was most likely to blame. “Oysters harvested from sewage-contaminated waters will feed on the faecal residues,” it said.
Graham Larkin, operations manager at Colchester Oyster Fishery, which supplied the Fat Duck, said the vast majority of oysters were safe to eat but action needed to be taken.
“Fisheries are being affected by this all over the country. We want to see the water cleaned up,” Larkin said.
He now conducts rigorous tests for norovirus on oysters from the River Colne in Essex. Anglian Water has sewage treatment works on the river, which flows through Colchester, and overflow pipes which can discharge sewage during very wet weather.
Gary Jones, executive head chef at Blanc’s Le Manoir in Oxfordshire, said the restaurant now only served oysters that had been through a purification process and had been tested for norovirus. “We have to be confident that what we put on the menu is not going to harm anyone,” he said.
Jones said there was “not a shadow of a doubt” that oyster contamination was caused by sewage and the water companies should be held to account over discharges. “What we are doing to the seas is horrific. We should be taking this more seriously,” he said.
Water companies are allowed to dump raw sewage into rivers and the sea during wet weather to stop it backing up into homes, but oyster producers want to see more investment to limit the amount that is discharged.
Anglian Water said there was no proven link between its sewage discharges and contaminated oysters. Water UK, which represents water companies, said the industry had spent billions of pounds to improve the sewer system and as a result water quality in rivers and bathing areas had significantly improved.
Jon Ungoed-Thomas
http://www.timesonline.co.uk/tol/news/environment/article7114086.ece
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