Triazine health tests 'flawed'
Apr. 29, 2009
Tasmania's biosecurity chief has conceded that the state's monitoring of potentially harmful pesticides in waterways is flawed and may need to be replaced by a better-targeted program.
The current program, involving the testing of rivers and streams for pesticides at 55 locations, has for years been used to reassure the public about the effects of pesticide sprays on water.
However, Alex Schaap, the Government's general manager of biosecurity and product integrity, told The Australian the sites tested were not necessarily the best for detecting contamination.
"The monitoring sites exist because they are sites surveyed for other purposes," he said.
"If you wanted to look at triazine (herbicide) contamination, you would want to look at different sites."
Tasmania is reviewing regulation of the triazine chemicals atrazine and simazine, after a state-commissioned report revealed that they remain in the environment for up to three times longer in cool-climate regions.
The report, revealed in The Australian this month, concluded that, because of triazine chemicals' longer half-life in cool conditions, ability to leach into soils and widespread use, they represented "the most significant environmental risk for water quality".
Mr Schaap's comments about the limitations of the monitoring regime in detecting triazines supports criticisms of the program by groups campaigning for tougher restrictions on pesticide use.
Alison Bleaney, a Tasmanian GP and anti-pesticides campaigner, said: "It is the monitoring program you have when you don't want to find anything."
She said the program tested too far downstream and this gave misleadingly low detection rates.
While Tasmania had a separate flood-event water-testing program, Dr Bleaney said, there was insufficient testing in many areas after major rains, which washed chemicals into waterways.
She said the current testing regime, which frequently detects triazine and other chemicals, despite its limitations, covered only 18 of 130 chemicals used in water catchments.
There is growing concern among health professionals about the repeated detection in waterways of chemicals, such as the triazine herbicides.
Banned in Europe, they have been linked to damaging genetic changes in human cells, cancer in laboratory animals and chemical castration of frogs.
The director of Public Health, Roscoe Taylor, earlier this month expressed unease about their potential health implications and urged an end to their use in aerial spraying in water catchments.
The national pesticides regulator, the Australian Pesticides and Veterinary Medicines Authority, has sought updated advice on the effects of triazines.
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