21 May 2019

SPOTLIGHT ON: Risk to baby seals from chemicals in mothers’ milk

SPOTLIGHT ON: Risk to baby seals from chemicals in mothers’ milk

A seal with seal pup

How can we give our oceans a ‘health-check’? The surprising answer may be through the wellbeing of seals…

An Abertay study warned that baby seals around the UK coast are at risk from toxic chemicals present in their mothers’ milk. 

Long-lasting chemicals from man-made contaminants have been recognised as harmful to wildlife since the 1970s, with marine mammals facing the biggest threat because they feed at the top of the food chain.

A substance ban designed to stop the damage has been in force since the early 2000s and helped reduce the levels of these chemicals, which enter the environment from the likes of paints, sealants, industrial lubricants, electrical transformers and pesticides.

However a study, led by Abertay, in partnership with the Sea Mammal Research Unit at the University of St Andrews and colleagues in Belgium, has shown that ban may not go far enough to protect wildlife.

The team found that the chemicals - known as PCBs (Polychlorinated Biphenyls) and DDT (Dichlorodiphenyltrichloroethane) - can interfere with the way seal blubber tissue works, even at low exposure levels, potentially altering the way pups gain fat vital to their survival.

Part of the so-called “dirty dozen” marine pollutants, these chemicals are banned from production and release into UK waters under the Stockholm Convention, but still make their way into the sea through incineration, effluent and landfill, and can travel a long way from where they were released.

Principal Investigator Dr Kimberley Bennett 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.

“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.”

Conducted on the Isle of May in the Firth of Forth, the study, funded by the Natural Environment Research Council (NERC), focused on grey seal pups in their first weeks of life.

The research was the subject of significant media interest, covered by a high number of outlets including the BBC, The Scotsman and The Independent. 

To read the full study visit https://pubs.acs.org/doi/10.1021/acs.est.8b04240

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