Recycling giant Suez says the powerful herbicides that contaminated a batch of compost produced at its Melbourne facility late last year, killing hundreds of home vegetable gardens, came from council green waste.
- California banned similar herbicides from urban and commercial use in 2001
- The contaminated compost falls within Australian standards
- An environmental scientist says the standards are inadequate
“Feedstock obtained from municipal sources contained traces of the agricultural herbicides dicamba, 2,4-D, MCPA, triclopyr and picloram,” a Suez spokesperson told the ABC.
“These are herbicides that would not normally be expected to be found and are therefore not ones for which testing is required.
“We continue to work at determining their source.”
Chris Williams, who lectures in Urban Horticulture at Melbourne University, said he was shocked to find out the herbicides came from a council.
“I really thought this is the worst-case scenario,” Dr Williams said.
“I was hoping we were dealing with manure. That would have been relatively easy to regulate.
“But if we’re getting residual herbicide in municipal green waste, that’s a lot more complex.
Suez began testing samples after hundreds of home gardeners across Victoria reported their summer vegetable patches were killed or severely damaged by soil mixed with contaminated compost produced about October last year.
But Dr Williams does not believe this is a one-off event.
“This has been a well-recognised problem overseas in the United Kingdom and the United States for well over 20 years.”
‘The big companies have the loudest voices’
The US state of California banned similar herbicides from urban and commercial use in 2001, when they were detected as contaminants in commercial compost.
Stephen Grealy was heavily involved in the campaign as an environmental executive with the City of San Diego.
Now back in Australia, he says when he saw the ABC’s report on contaminated compost last week he knew exactly what he was seeing.
He said taking on a giant manufacturer like Dow Chemical in the US was not easy.
“It was a big win,” Mr Grealy said.
“The big companies have the loudest voices when it comes to government regulation. And it took a while for us to penetrate that fog.”
Environmental scientist says standards ‘outdated’
Suez maintains — correctly — that the contaminated compost it produced in October fell within Australian standards.
But environmental scientist Paul Harvey said the standards were useless at stopping these types of herbicides, which could cause serious damage at levels of just three or four parts per billion.
Nor do they require companies like Suez to even test for them.
“The standards are outdated and need to be tightened up,” Dr Harvey said.
Suez says it has increased its testing regime and “hopes to be in a better position to reinforce its measures against unwanted additives once further analysis has been received”.
But Mr Grealy says changes need to come from government, not private companies.
“It’s not feasible for companies like Suez to be able to control it at their gate,” he said.
“They can’t check it every load that comes in. And this chemical could be coming from anywhere.”
Dr Williams said any investigation should look at where the council waste came from — and stop it from ever happening again.
“But if the main problem is turf that is coming off sports fields and golf courses, then it’s also going to have to be regulated.
“Those landscapes cannot provide organic waste into the municipal green waste system, otherwise this is going to go on forever.”