Water plan a 'health gamble'

An internationally recognised cancer expert has likened WA plans to recycle sewage water for drinking to "playing Russian roulette" with public safety.

US scientist Steven Oppenheimer, director of cancer and development biology at California State Northbridge University, said "toilet-to-tap" water posed an inherent public health risk and should be used only as a last resort.

He said there were too many unknown chemicals and pathogens for the process to be foolproof.

Professor Oppenheimer's comments, which were echoed by a leading Australian researcher into infectious diseases, came after State Water Minister Bill Marmion revealed he wanted to fast-track treated wastewater into WA's drinking supplies.

Mr Marmion said a trial to inject recycled effluent into Perth's groundwater clearly worked and he believed it should be expanded to produce up to 90 billion litres, provided it met health benchmarks.

Australian National University microbiologist Peter Collignon said yesterday that current testing standards in Australia could not account for all the potential harmful agents in sewage.

He cited a National Water Commission report, released this week, to argue there were shortfalls in the arrangements safeguarding public water supplies.

The report warned of "emerging contaminants" in alternative supplies, including recycled effluent but found "there are outward signs that the broader regulation of urban water quality in Australia is not equivalent to best practice".

"To me, the fundamental issue is you only do it if you really don't have any other viable option, which for most areas of Australia is not true," Professor Collignon said.

"But if you do (have to) do it because you don't have any other choices, then I think it's really important that you do lots of tests, including those for viruses and in general they are not done very well very often."

The Health Department, which has been monitoring samples from the aquifer recharge trial, defended the rigorousness of its testing and denied suggestions some pathogens, including hormones, could not be detected.

Jim Dodds, the department's environmental health director, said samples had been screened for 250 chemicals and four microbial recycled water quality indicators since the trial began in November.

All of the samples had met Australian guidelines. "If we were asked to consider an expansion of the trial … we would conduct a formal risk assessment," Mr Dodds said.

He said this risk assessment would include the amount of water being produced and the length of time it might take for injected water to travel through the aquifer.