Recent sampling of water at Telarah Lagoon has revealed the presence of a high concentration of blue green algae with a red alert now issued for the site.
The recent flooding is believed to, at least partially, caused the outbreak of the microscopic cells.
High temperatures combined with high nutrients and low flow provide the perfect conditions for blooms to grow.
They appear as green discolouration of the water and accumulate on the surface and around the water’s edge, as well as producing a strong, earthy smell.
Maitland City Council Manager Environment and Sustainability Catherine Pepper says a red alert means algae numbers are high, and a potential health risk to people and animals.
“Blue green algae can be a serious environmental and human health problem, with the release of toxins and skin irritants,” she said.
“Anyone visiting Telarah Lagoon should avoid contact with the water while the bloom remains. Domestic pets and livestock should also be prevented from coming into contact with this water body.”
Blue green algae may cause severe stomach upsets, nausea and skin irritation in both people and animals following contact.
The toxins cannot be removed by boiling the water.
People who believe they may have been affected by the algae are advised to seek medical treatment.