A RED alert level warning (high alert) for blue-green algae has been issued for the Hunter River, upstream of Glenbawn Dam in the Upper Hunter.
Sampling by WaterNSW displayed significant levels of a variety of potentially toxic species.
The species of blue-green algae identified are potentially toxic and may cause gastroenteritis in humans if consumed, and skin and eye irritations after contact. Boiling the water does not remove algal toxins.
A Red Alert level warning indicates that people should not undertake recreational activities where they may come into direct contact with the water, such as swimming, watercraft or other water-based activities.
People are advised not to enter the water, swim or bathe in water, or drink untreated water drawn from the river while this red alert level warning is in place.
Contact with the water may also pose a threat to livestock and pets. Livestock owners are advised to check stock water supplies for blue-green algae.
They are also advised to remove stock from foreshores and avoid extraction of water, in areas where surface scums are visible or blue-green algae are suspected.
It is highly advisable for livestock owners in this immediate area to source alternate watering supplies.
People should not eat mussels or crayfish from Red Alert warning areas. It is also advisable not to fish, however if any fish are caught, they should be cleaned and washed thoroughly in uncontaminated water and all internal organs disposed of appropriately before consumption.
Blue-green algae usually appear as green paint-like scums on the water, near the edges, or as greenish clumps throughout the water. It makes the water appear dirty, green or discoloured and generally has a strong musty or earthy odour.
It occurs naturally and can reproduce quickly in favourable conditions where there is still or slow-flowing water, abundant sunlight and sufficient levels of nutrients.
It is not possible to predict how long the algae will remain at high levels. Increased monitoring by WaterNSW will begin and the alert will be lifted as soon as the high levels of algae dissipate.
People who believe they may have been affected by blue-green algae are advised to seek medical advice.
Livestock owners who believe their stock may have been affected by blue-green algae should contact the nearest Local Land Services.
Updates about blue-green algae blooms and red level warning areas can be obtained by visiting WaterNSW's algae webpage or phoning 1800 999 457.