| More toxics added to 'dirty dozen' list|
|The UN has agreed to phase out nine more persistent chemicals widely used in farming and industry, after a meeting in Geneva.|
The nine pesticides and industrial chemicals join 12 substances targeted for elimination under the 2001 Stockholm Convention on Persistent Organic Pollutants (POPs).
Trade in some of the chemicals can amount to billions of dollars a year, but countries at the United Nations conference agreed they are so dangerous that alternatives must be found.
"Just five years after this convention came into force, we will have nine new chemicals added to the list of those that the world community agrees we need to control and ultimately get rid of," says Achim Steiner, executive director of the UN Environment Programme (UNEP), which hosted the conference.
Donald Cooper, executive secretary of the Stockholm Convention, says the banned substances were exceptionally dangerous because they can damage reproduction, mental capacity and growth and cause cancer.
He says the chemicals are found everywhere, take years to degrade and they accumulate in the food chain.
"In most cases the question is not simply how do we control them, but how we eliminate them," says Cooper.
Question of timing
According to Cooper, governments differed about how fast they should be phased out, especially when there are no alternatives.
One of the newly proscribed chemicals is a pesticide called Lindane. It has widely been replaced in agriculture, but in some countries it is still used to tackle head lice and so will be phased out over five years instead of the standard one year.
According to the Australian Pesticides and Veterinary Medicine Authority website, Lindane is still registered for use in Queensland, and is used for the prevention of white grubs and symphylids in pineapples.
Perfluorooctane sulfonic acid (PFOS), also added to the list, appears in a wide range of products from electronics components to fire-fighting foam, and trade in it amounts to billions of dollars a year. With no alternatives to some of its applications, it will be restricted rather than eliminated immediately.
Steiner says the challenge is to resolve two conflicting objectives - harnessing the power of science and the chemicals industry and dealing with its negative impact.
Sometimes the conflict is not obvious.
The inventor of the pesticide DDT won a Nobel Prize for Medicine in 1948 because of its efficacy in killing mosquitoes that transmit malaria. DDT has since been found to be toxic and is banned as a pesticide for crops as one of the original "dirty dozen" under the Stockholm Convention - but it is still widely used to fight malaria.
The UNEP and the World Health Organization announced a plan to rid the world of DDT by 2010 by developing environmentally friendly ways to fight malaria.
Hard to let go
Jo Immig of the Australian-based National Toxics Network says the addition of PFOS to the Stockholm Convention is significant.
"If it had not been listed then it would have gone against the validity of the convention," she says.
According to Immig, the addition of PFOS and other POPs was strongly resisted by developing such as China and India.
"The difficulty is that they have become so pervasive in so many goods, people are not going to give them up unconditionally," she says.