BANNED chemicals pose a major risk to baby seals through their mother’s milk, Scottish researchers have found.

Restricted substances have become “locked in” to the environment and could drive push coastal animals to extinction, it is claimed.

Action was taken to limit the use of pesticide DDT and industrial agents known as PCBs 20 years ago in a bid to protect the environment from harm.

Scientists had been warning of the potential danger to wildlife since the 1970s.

But research published today reveals the substances have become “locked in” to the ecosystem and cause harm to infant seals whose mothers’ bodies have accumulated levels of DDT and PCBs through the food chain.

Consumed through the eating of fish, the chemicals enter the mothers’ milk, exposing the newborns to the old pollution problem and reducing their chances of reaching the age of one.

Principal investigator Dr Kimberley Bennett, of Abertay University in Dundee, says relatively low levels can harm marine mammals in unforeseen ways.

She said: “We’ve known for a long time that high levels of these chemicals are very dangerous and can hamper reproduction and immunity in marine mammals. They may even drive some populations towards extinction.”

Working with the Sea Mammal Research Unit at the University of St Andrews and colleagues in Belgium, Bennett’s study looked at grey seals pups in the first weeks of life.

The team focused on animals on the Isle of May in the Firth of Forth.

The toxins – these chemicals are banned from production and release into UK waters under the Stockholm Convention – are said to be present in the waterway as a result of incineration, effluent and landfill.

Known to interfere with seal blubber tissue, it is feared they could affect the way pups gain fat, potentially threatening their survival in Scotland’s harsh waters.

And, because a significant number of the world’s grey seal population lives in Scotland, the situation could have serious consequences for the species.

Around 40% of the overall 350,000-400,000 grey seal total are found in UK waters, with Scotland home to about 90% of this group.

Bennett said: “Efforts to reduce levels in the environment have been successful.

“But our new research shows that blubber, which is a vital for seals and whales, could be vulnerable to harmful effects of PCBs and DDT at levels much lower than previously thought.”

Co-investigators Dr Kelly Robinson and Professor Ailsa Hall of the Sea Mammal Research Unit at St Andrews, added: These chemicals can reduce the likelihood that a seal pup will survive to its first birthday.”