Lead gunshot 'poisoning UK birds'
Lead poisoning from spent gun ammunition is a major cause of death among UK waterbirds, scientists say.
Scientists found 10% of dead waterbirds collected from 1971 to 2010 died from lead poisoning and a third of a sample of living birds were also affected.
They said it showed laws restricting use of lead gunshot were not working.
Shooting groups rejected this saying that few people now used lead gunshot but there was a "historical legacy" of lead shot in the environment.
The life of waterfowl
The study was conducted by the Wildfowl and Wetlands Trust (WWT) and is published in the European Journal of Wildlife Research.
It shows the results of data analysis from 2,365 post-mortem examinations conducted on individual waterbirds across 28 species that were recovered near WWT centres across Britain over the past 40 years.
Up to 438 pieces of lead shot were found in some of the dead birds with the primary cause of death being lead poisoning in one in 10 cases.
But the deaths across 14 species of ducks, geese and swans could be just the tip of the iceberg, according to the scientists.
They reasoned that poisoning would have been likely to contribute to a premature death, which could then have been attributed to other causes.
In addition, they said that birds that were close to death often become reclusive and may have died in places where they were not spotted and collected.
"Lead poisoning has always been known as the invisible disease, what you tend to get is small numbers of birds getting sick and dying all the time," said Dr Debbie Pain, Conservation Director at the WWT and co-author of the research.
"And when you get small numbers of birds dying, they are very rapidly taken by scavengers," she said.
The scientists also took blood samples from 285 live waterbirds at four WWT centres in Gloucestershire, Norfolk, Lancashire and Dumfriesshire.
Lead was detected in all blood samples with 34% showing high blood lead levels.
Waterbirds are poisoned by lead gunshot after it has been fired.
Where the lead lies on the ground, the birds can ingest it while grazing, either mistaking the pellets for food particles or for grit, which they take in to help grind up food in their gizzards.
As the lead is absorbed into the body of birds, the toxicity level builds and inhibits the functioning of organs.
The WWT said it can paralyse stomach muscles, causing food to become packed into the intestine.
End Quote Martin Spray Chief Executive, Wildfowl and Wetlands Trust
Despite the law brought in over a decade ago to protect wetland birds, nothing has changed - clearly an effective solution is long overdue”
It was because of deaths from ingested lead gunshot that legislation was introduced in line with an international agreement called the African Eurasian Waterbird Agreement (AEWA), according to Dr Pain.
The legislation controls where lead shot can be used and differs between the home nations of the UK.
"There have been various different bits of legislation that have come into play over that time [spanned by the study]," she said.
"We looked at whether the introduction of any of the legislation resulted in a... significant reduction in either the proportion of birds with elevated blood lead that are living, or the proportion of birds that have died of lead poisoning."
End Quote Jeffrey Olstead British Association of Shooting and Conservation
Lead shot doesn't just dissolve and disappear”
The study found no evidence of a significant change after changes in the law.
"In the UK lead poisoning from shooting kills a large number of our wild birds each year and makes many more very sick," said WWT chief executive Martin Spray.
"Despite the law brought in over a decade ago to protect wetland birds, nothing has changed. Clearly an effective solution is long overdue," he said.
The WWT study recommended a "review and extension" to existing legislation.
But the UK's largest shooting organisation, the British Association of Shooting and Conservation (BASC) has rejected the idea.
The study does not prove where the lead shot has come from, according to Jeffrey Olstead from the BASC, which "muddies" the findings.
"Lead shot doesn't just dissolve and disappear. You've got this historical legacy of lead shot that has been there for donkey's years and unfortunately will remain there for donkey's years," he said.
"Even though we're not adding to it, it's clearly there in such quantities that it clearly can cause problems."
He said there was no need for a change in the law to match the outright bans on lead shot that exist in other countries, such as Denmark.
"The [UK] government I think very sensibly brought in a ban that said don't use lead where it's going to cause a problem and where it has welfare implications," he said.
But Dr Pain from the WWT is not convinced that existing rules are actually being obeyed.
She said that a 2010 Defra-funded compliance study [PDF] completed by the WWT working with the BASC suggested that there was a widespread problem of people ignoring the law.
A BASC survey of its membership found that of those obliged to use non lead ammunition "45% indicated that they sometimes or never comply with the Regulations."
But Mr Olstead said this concern's time had passed.
"For many generations lead shot has been used and of course changing from those established practices can be tricky which is why it has taken a while, I think, to get people to change," he explained.
"People are now being very good about compliance," said Mr Olstead, suggesting that the sales figures of non toxic alternatives to lead shot support this.
"It seems to be the case that we are getting greater compliance now, because everyone seems to be using [non toxic alternatives such as] steel or heavy shot or bismuth," he said.