KEY POINTS:
- Should insect sprays banned overseas be outlawed in NZ?
Insect sprays that have been banned or restricted overseas will be reviewed in the next few months to determine whether they should still be used in New Zealand.
The Environmental Risk Management Authority (Erma) - which last week approved the continued use of the controversial 1080 poison on possums and other pests - will reconsider three chemicals, including one that is being phased out in the United States and Canada.
It will also urgently reconsider the status of pentachlorophenol, better known as PCP, the timber preservative that was banned in 1998 for its toxic effects on people and the environment.
PCP was accidentally included in a list of permitted chemicals last year, even though it has long since been replaced by other products in timber and agriculture.
The authority will also reassess a further 16 substances over the next five years, including anti-fouling paints and the fumigant methyl bromide, which has been linked to the deaths of four Nelson port workers who succumbed to motor neurone disease.
The three products to be reviewed in the next few months are:
* Azinphos-methyl: Also known as AZM, this insecticide is being phased out in the United States and Canada and restricted in Australia, after complaints from US environmental groups that it poisons farm workers.
Erma says on its website that AZM is used in one spray in New Zealand on crops such as grapes, kiwifruit, pipfruit, stonefruit and potatoes. It does not know how much is used each year and has no information on how much the chemical has affected the environment or whether it has affected people's health.
* Endosulfan: This insecticide is used on a wide variety of plants including tomatoes, potatoes, onions and sweetcorn. It has been banned in some countries and is restricted in others.
The chemical has been controversial in New Zealand lately. Three weeks ago Waimauku farmer Carl Houghton was fined $15,000 for using the spray on his cattle farm, which led to the suspension of New Zealand beef exports to Korea in September 2005.
About the same time, public concern forced a delay in spraying a Mt Maunganui rugby field with Thiodan - whose active ingredient is endosulfan - to prevent damage to the surface by earthworms.
* Methyl-parathion: This insecticide is no longer used in New Zealand but was previously used on a wide range of crops in a product called Folidol M50.
It has been banned in Europe, withdrawn from crops eaten by children in the United States and is under review in Australia.
The Green Party, which believes pesticides are overused in New Zealand, is particularly concerned that some pesticides banned overseas are still being used here.
The Greens' co-leader, Jeanette Fitzsimons, said the party had given its own list of the "dirty dozen" worst chemicals to the Government and Erma to try to get them banned.
"We also have concern what [pesticides] will do to our markets. European and Japanese markets are saying, 'We don't want food with any chemical residues'."
Ms Fitzsimons wants to see Erma become more active in phasing out the worst pesticides, and wants a more concerted drive to have organics replace chemicals.
Just how much long-term damage is being done by pesticides in New Zealand is unclear.
The New Zealand Food Safety Authority last week produced survey results that showed breaches in the chemical residue limits in some vegetables and meat, but nothing to put consumers at risk.
A survey of groundwater in 1994 by the Institute of Environmental Science and Research detected pesticide in 13 of 79 wells tested throughout the country.
But none of the 13 had levels of pesticide to a level considered unsafe for drinking.
Dr Michael Beasley, a medical toxicologist at the National Poisons Centre, said his own view was that pesticides "get a very bad press".
"They are an easy target. And there are risks with them, but everything in life comes back to the risk-benefit balance, and I believe most of them can be used safely provided the controls are adequate."
Pesticides were tested on animals more than any other type of chemical, whether natural or synthetic.
But it was very difficult to calculate the degree of long-term harm caused by exposure to pesticides.
Doctors could diagnose a patient's illness as a result of chemical exposure, but "not all patients go to the doctor, and not all doctors report these causes".
