General News
4 August, 2026
Banned fungicide detected at Lake Fyans
TRACE detections of a fungicide banned almost 20 years ago have raised questions about its continued presence in raw water from Lake Fyans, although authorities say the findings do not indicate the region’s drinking water is unsafe or that benomyl is still being used illegally.
Friends of the Earth identified nine detections of benomyl in untreated Lake Fyans water between 2017 and 2026 through data obtained from Victorian water authorities under Freedom of Information laws.
Lake Fyans supplies water to Ararat, Stawell and Great Western, but the detections were recorded in raw water before treatment.
Across Victoria, Friends of the Earth reported 141 detections in 43 water supplies, making benomyl the sixth most frequently detected pesticide among almost 2000 results it examined.
“How on earth is this fungicide still being detected 20 years after it was banned in Australia?” Friends of the Earth land-use researcher Anthony Amis said.
Benomyl, once sold under the trade name Benlate, was used on fruit, nuts, vegetables and field crops before being banned by the Australian Pesticides and Veterinary Medicines Authority in 2006.
Friends of the Earth says benomyl is toxic to soil and aquatic organisms and other invertebrates, meaning the findings raise environmental questions even though the trace detections do not indicate a risk to treated drinking water.
Mr Amis said the detections could reflect benomyl stored on farms or obtained through other means, but also acknowledged they could represent a closely related chemical identified or reported as benomyl.
Agriculture Victoria urged caution in interpreting the findings.
“The detection of benomyl in environmental samples does not, on its own, indicate recent or illegal use,” an Agriculture Victoria spokesperson said.
“Benomyl was banned by the Australian Pesticides and Veterinary Medicines Authority in 2006.
“No products containing benomyl are currently registered for use in Australian agriculture and its use is prohibited.”
The department said it had received no reports of benomyl being used in Victoria.
It said benomyl rapidly converted into carbendazim in the presence of moisture, although the process occurred more slowly in soil. Carbendazim itself breaks down more gradually, with an estimated half-life of six to 12 months on bare soil.
Agriculture Victoria did not identify the source of the Lake Fyans detections or confirm whether lawful use before 2006 could explain results recorded more than a decade later.
“Agriculture Victoria takes reports of suspected chemical misuse seriously and assesses information regarding potential breaches of Victoria’s agricultural chemical laws,” the spokesperson said.
GWMWater said its drinking water remained safe and continued to meet Australian Drinking Water Guidelines.
“The detections were extremely low – measured at many hundreds to thousands of times below the Australian health guideline value,” the authority said.
The highest concentration detected in raw water sampled by GWMWater was 0.09 micrograms per litre. By comparison, the Australian Drinking Water Guidelines set a health limit of 90 micrograms per litre for benomyl in treated drinking water.
“For the past four years detections of Benomyl have been at or below the limit of detection,” GWMWater said.
The authority tests for more than 90 pesticides and other chemicals as part of its routine water quality monitoring program.
Read More: Lake Fyans