Blue-green algal red alert issued for Lake Cargelligo

Blue-green algal red alert issued for Lake Cargelligo

24 March 2022

WaterNSW has issued a red alert advisory for high levels of blue-green algae at Lake Cargelligo.

A red alert warning indicates that the public should avoid coming into physical contact with untreated water at the site until the red alert warning is lifted.

This advice includes recreational activities such as swimming, along with any activity that brings the user into direct physical contact with untreated water.

Blue-green algae is potentially toxic and may cause gastroenteritis in humans if consumed, while skin and eye irritations can also occur after contact. Boiling the untreated water does not remove algal toxins.

This red alert warning applies only to untreated water at the identified location and will remain in place until monitoring and test results confirm that the risk is sufficiently diminished.

People who suspect they have been affected by blue-green algae should seek medical advice.

Contact with untreated water subject to a red alert can also pose a risk to livestock and pets, and livestock owners are advised to check stock water supplies and remove stock from foreshores where surface scum is visible or blue-green algae is suspected.

It is not possible to predict how long the algae will remain at high levels. Regular monitoring will continue, and the alert will be lifted as soon as the high levels of algae dissipate.

For information regarding treated drinking water supply the public should contact their local council or local water utility.

People should not consume mussels or crayfish from red alert warning areas. Before consumption, any fish caught in an area subject to red alert should be cleaned and washed thoroughly in uncontaminated water.

Blue-green algae is naturally occurring and can reproduce quickly in favourable conditions where there is still or slow-flowing water, abundant sunlight and sufficient nutrients.

Updates and information about blue-green algae blooms and red level warning areas can be obtained by visiting –


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