Southern Grampians Shire Council has warned grey water from washing machines and showers usually contains phosphorus from detergents and washing powder and is one of the nutrients causing blue-green algae growth in Lake Hamilton.

The dry conditions of the past couple of years have led residents to divert grey water on to their gardens but recent rain has meant the soil is saturated and any grey water put on the garden will find its way into stormwater drains then into Lake Hamilton or other water courses.

The shire’s environmental health co-ordinator, Pauline Porter, regularly monitors blue-green algae levels in Lake Hamilton.

She has also been testing nutrient levels in the lake water and has found high levels of phosphorus.

“Blue-green algae can be toxic to humans and animals, so council tests the lake water every week,” she said.

“If we find high levels of blue-green algae, we have to put up signage to warn the public. Contact with affected water from water skiing, fishing or rowing can be harmful.”

Ms Porter said the council must close the lake when tests show high levels of the algae to protect the public from toxic effects.

“Council is concerned about the amount of nutrients entering the lake water,” she said.

“It could be from fertiliser run-off, sheep and cattle upstream and from contaminated stormwater.

“All these things are helping the blue-green algae to thrive and causing massive problems for lake users.”

Hamilton angler Graham Young is unhappy about the ongoing blue-green algae problems in the lake.

“The blue-green algae issue is causing major problems, not just for us but for other lake users,” he said.

“It is really important to stop all these nutrients from getting into the lake and the Grangeburn.”

For more information contact Ms Porter on 5573 0256.

tliptai@standard.fairfax.com.au