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Blue-green algae Blue-green algae

Blue-green algae (BGA) or cyanobacteria occur naturally in marine and freshwater environments such as rivers and lakes. Some species of blue-green algae are known to produce toxins that can be harmful to both humans and animals.

The effects of blue-green algae on humans can include rash, nausea, eye and ear irritation, headache, vomiting, abdominal pain, diarrhoea, gastroenteritis, muscle weakness, pneumonia and paralysis. These symptoms can occur by coming in contact with the water through recreational activities such as swimming, canoeing, boating, eating fish or other aquatic life or ingesting untreated water.

The population of blue-green algae in Lake Lenthall and the Burrum Weirs varies throughout the year. Populations are known to increase under high nutrient conditions, still water with low turbulence, warm sunny weather and weather patterns that are stable for a long time.


Wide Bay Water monitors blue-green algae in all of its water storages.

A Blue-green Algae Alert System has been developed to advise visitors of recreational hazards associated with blue-green algae.

The recreational hazard varies depending on the number and type of blue-green algae present in the water body. As the hazard status increases so does the likelihood of irritation or adverse health outcomes if you come in contact with the water.

  • High level - indicates there is a high possibility of some form of irritation.
  • Moderate level - indicates that there is a possibility of irritation.
  • Low level - indicates there is unlikely to be health problems to the average person.

It is important to remember that some people are more sensitive than others and this should be considered before coming in contact with the water.

Wide Bay Water may restrict certain activities when the hazard status reaches Moderate or High.

Below is the current hazard status at Lake Lenthall and the pondage of Burrum Weir #1.

This hazard system is specific to recreational contact with water.

Risk at Lenthall Dam Risk at Burrum Weir #1 Risk at Teddington Weir


Visitors are advised not to drink water directly from Lake Lenthall or the Burrum.  Boiling water will also not reduce the risk from blue-green algae. Wide Bay Water advises to only drink treated water.

Wide Bay Water ensures its treatment plants remove blue-green algae and its toxins to make the raw water drawn from Lake Lenthall and the Burrum Weirs safe for drinking.