Testing Confirms Disappearance Of Blue-Green Algae
January 11 2013
Testing Confirms Disappearance Of
A potentially toxic blue-green algae which emerged in some Otago waterways in December has dissipated.
The Otago Regional Council (ORC) had issued warnings to the public to keep their distance from Lake Waihola, the Tomahawk lagoon, and the Taieri River at Henley because of the presence of the algae.
When present, the blue-green algae can produce toxins which can cause illness, irritation of the skin, eyes, nose, and mouth in people.
ORC manager resource science Matt Hickey said water sampling at the three locations this week confirmed that the blue-green algae had dissipated, reducing the potential risk to people and animals of illness through contact with the algae.
Mr Hickey said that while this was good news for people frequenting Lake Waihola, the Tomahawk lagoon, and the Taieri River at Henley, they still needed to be alert to the possible presence of another kind of potentially toxic algae known as Phormidium.
Unlike the blue green algae which has caused problems in Lake Waihola and Tomahawk lagoon. Phormidium is found in rivers and streams, and typically forms a thick brown-black slimy algae mat found on large rocks, stones, and cobbles.
If the mats detach, they may float downstream to become caught up in other debris such as sticks. When the Phormidium mats die and dry out, they become light brown or white. Either fresh or dried, the algae can be highly toxic and potentially harm animals and people.
Dogs are particularly susceptible to poisoning from both mat-forming and free-floating toxic algae.
“Many dogs enjoy being in the water and can eat these algae intentionally or by accident, which can have tragic results,” Mr Hickey said.
Symptoms of poisoning in animals exposed to the type of toxins present in Phormidium include lethargy, muscle tremors, fast breathing, twitching, paralysis, and convulsions. In extreme cases, death can occur within 30 minutes after signs first appear.
Where humans become ill or are suspected of being ill after swallowing water containing algal bloom, medical advice should be sought immediately. Likewise, if animals become sick, a veterinarian should be contacted.