Monday, November 23, 1998 Published at 08:03 GMT
Sea life changing sex
'Gender bender' chemicals are impairing otters' fertility
Environmental campaigners say chemicals that interfere with the hormone system are causing increasing damage in the rivers and coastal waters of Britain.
The chemicals are known as endocrine disrupters (EDCs), or "gender benders".
They include some pesticides, dioxins (which can be given off by incinerators), and many other synthetic substances.
These EDCs mimic natural hormones, the body's chemical messengers, or block the cells that act as hormone receptors.
Effects on sexual development
That causes disruption of the endocrine system which controls growth and reproduction.
The campaigners say the effects of EDCs are now known to be damaging the endocrine systems of fish in the estuaries of the Mersey, the Tees and the Tyne.
In the Thames estuary and other major British rivers, they say they have found flounders which have become feminised.
Both common and grey seals have been found with suppressed immune systems.
And otters are suffering from lower fertility and reduced penis size.
The campaign groups which have sounded the alarm are Friends of the Earth, Greenpeace, the Marine Conservation Society, the Whale and Dolphin Conservation Society, and the World Wide Fund for Nature.
Most chemicals' effects unclear
They say that little is known on the toxicity of about 100,000 chemicals currently available for use.
And they say this means "a global-scale experiment is being conducted where humans and the environment are being exposed to unpredictable cocktails of chemicals".
So someone who eats a lot of fish could expect to be absorbing EDCs in their diet.
Like many other chemicals, their effects tend to be more severe in children. And one EDC may work with another chemical to produce an effect that neither could achieve in isolation.
Although scientists have identified only about 100 chemicals as EDCs, the groups say these are believed to be just the tip of the iceberg.
A failsafe approach
They want industry to take responsibility for eliminating the threat of EDCs in the marine environment, and to make the transition to clean production of safer chemicals.
And they say the government should act on the precautionary principle, refusing to allow chemicals to be discharged unless they have been proven to be safe beyond reasonable doubt.