(31 positive samples 2008-2012: Simazine, Atrazine, Metolachlor, DEET and Glyphosate)
PESTICIDES have been detected upstream of a reservoir that feeds Melbourne’s drinking water supply, sparking calls by an environmental group for an urgent upgrade of the dam’s filtration and treatment plant.
On eight occasions in 2010-11, the levels of pesticides, including simazine, atrazine and DEET, at Sugarloaf reservoir, north-east of Melbourne, were recorded above safe European Union drinking water standards, according to Melbourne Water data obtained by Friends of the Earth through freedom of information.
The pesticide levels were within Australian safety limits, but Friends of the Earth spokesman Anthony Amis said it highlighted problems with the Winneke treatment plant at Sugarloaf, which ”was never intended to filter out pesticides”.
”We’d argue that as a precautionary principle the treatment process at Winneke should be upgraded to filter out these pesticides. Elsewhere in Australia, activated carbon has been used to filter out pesticides.”
Melbourne Water’s own risk assessment – published in the Friends of the Earth report, Issues regarding Melbourne drinking water and pesticides – stated that ”of any of the catchments, biocides are most likely to be found in Sugarloaf”.
Melbourne Water also acknowledged that ”the health impacts of biocides are uncertain and generally of a chronic nature.
”It is possible that long-term exposure could cause cancer within a subset of the population resulting in shortened life expectancy in some people.” It also acknowledges that the impact of biocide contamination would be ”catastrophic”.
Since 2010, Friends of the Earth has resisted attempts by the Eastern Golf Club to open a new course at Yering, one kilometre upstream from Sugarloaf, over fears chemicals used to maintain the greens could be washed into the reservoir in the event of a flood.
Water quality scientist Dan Deere, an expert witness at the Victorian Civil and Administrative Tribunal hearings on the golf course application, said treatment plants such as Winneke were not designed to remove pesticides although ”they will reduce pesticides to some extent”.
”Advanced treatment, such as ozone coupled with organic carbon, or reverse osmosis, would be required [to fully remove pesticides],” he said.
Dr Deere said the European Union guidelines were based ”on consumer expectations of no pesticides being present”.
If pesticide levels met Australian guidelines, ”they weren’t thought to present a public health risk”.
Dr Deere said if tougher guidelines were introduced for pesticides in water, they would have to be introduced for food as well.
”If you adopted a ‘zero detection’ approach to pesticides in water, you would need to consider what you’d do about foods,” he said. ”If pesticides are applied directly to foods you can see that the total amount of pesticide consumed by a person might be higher from those foods than from any trace levels that might end up highly diluted in the water.”
The general manager of asset planning at Melbourne Water, Paul Pretto, said he was ”very concerned at this alarmist interpretation of our own data” by Friends of the Earth.
”The simple fact is that all drinking water we supply has to meet very strict health guidelines. At no stage have pesticides been detected above the recommended health limits. They are many, many times below the health-based values in the Australian Drinking Water Guidelines.”