Roscoe Taylor revealed yesterday he had directed the timber company not to use the triazine herbicides – atrazine and simazine – to control weeds in its forest plantations in the Macquarie River catchment. This followed repeated detection of simazine in drinking water supplies for the town of Ross at levels more than double the national guideline.
Dr Taylor also told The Weekend Australian he believed the use of the chemicals in cooler states might need to be re-examined following evidence they were persisting longer in cool environments. “There have been two detections of simazine in drinking-water catchments in Tasmania in four years,” Dr Taylor said.
“From my point of view (it’s) three strikes and it’s out.” “If it can be demonstrated that these things are persisting (in the environment) despite good practice in their application, then maybe people need to look at whether or not their application in the Tasmanian setting is appropriate.”
The developments follow The Australian’s report earlier this week that American researchers had found that atrazine caused damaging changes to human cells at levels half those of Australia’s drinking-water health value.
“I’m regarding this matter as under investigation,” Dr Taylor said. “The issues include whether or not the triazine herbicides demonstrate greater persistence in the Tasmanian environment than they may, say, in a warmer climate.”
He had observed persistence of the chemicals in the Prosser catchment at Orford, on Tasmania’s east coast. “There was a fairly lengthy degree of persistence over many months – the chemical just stayed at very, very low concentrations,” he said.
The State Department of Primary Industries and Water was developing ways to assess the risks of chemical use in water catchments. Dr Taylor would then pursue the issue via the national Agricultural, Silvicultural and Veterinary Chemicals Council.
“Until those pieces of information are provided to me, I feel it is best to ask operators to avoid using this long-acting herbicide in that particular catchment, where there is a public drinking-water supply that was contaminated,” he said.
“My brief is to protect public health and I believe that the community should be reassured that in these cases, public health protection has occurred.” He said atrazine levels in the Macquarie River, a source of drinking water for the Midlands town of Ross, had ranged as high as 1.35 parts per billion, far above the Australian Drinking Water Guideline of 0.5 > ppb.
The level was far below health value levels and Ross’s water supply was already unfit for drinking because of algal contamination. “(However), it’s an unnecessary chemical to have in our drinking-water supply and therefore measures should betaken to reduce it,” Dr Taylor said.
Gunns had complied with his directive. “In fact, they indicated they would be seeking to review the application of chemicals on plantations,” Dr Taylor said. “I will be interested to see what that review brings forward.” Gunns confirmed that a review was under way.