Moves by the State Government to reduce the amount of nutrients flowing into the Swan and Canning Rivers have been dismissed as feeble by environmental groups and the Opposition.
Environment Minister Bill Marmion and Agriculture Minister Terry Redman announced today new regulations would come into force on January 1 requiring garden fertilisers to have less phosphorus.
Under the news limits, phosphorus levels must be cut from 2.5 per cent to 2 per cent, while controlled-release and processed organic fertilisers would no longer be exempt from tougher rules.
These latter kinds of fertiliser include blood and bone, composts and composted chicken manure-based products.
As he noted that phosphorus was a key contributor to toxic algal blooms, Mr Marmion claimed the move would materially improve the quality of waterways including the Swan and Canning Rivers.
"Further limiting the amount of phosphorus contained in home garden fertilisers will align more closely with plant requirements and reduce the excess that could end up in the Swan-Canning River system and other South-West waterways," Mr Marmion said.
Conservation Council of WA director Piers Verstegen said the Government's announcement was a step in the right direction but it fell significantly short of what was needed.
Mr Verstegen said the lion's share of nutrients that were flowing into Perth and South West waterways came from agricultural areas and the new limits would have little or no effect there.
"Pumping oxygen and drainage intervention is useful in buying time (for the Swan and Canning Rivers) but it's only going to buy us a little time, if anything, unless we address the source of the problem," he said.
Shadow environment minister Sally Talbot echoed the comments, saying the Government should never have abandoned the former Labor administration's plans to phase out water-soluble fertilisers.
Although Dr Talbot would not be drawn on what Labor would do if it was elected at the State poll in March, she indicated the party would move to re-adopt its 2008 position.