Toxic algal bloom in Selwyn River

by Mike Isle

Canterbury District Health Board’s Community and Public Health Unit has issued a health warning after potentially toxic blue-green algae (benthic cyanobacteria) was found in Selwyn/Waikirikiri River at the Whitecliffs Domain.

People and animals, particularly dogs, should avoid the area until the health warning has been lifted.

There are also other access points along the Selwyn/Waikirikiri River that may have cyanobacteria present.

People are advised to check for the presence of cyanobacteria and avoid contact.

Dr Ramon Pink, Canterbury Medical Officer of Health, said some of the cyanobacterial mats are accumulating along the river edge and are bright green in addition to the usual brown/black colour. They can produce toxins harmful to people and animals.

“Exposure may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms, visit your doctor immediately, also let your doctor know if you’ve had contact with dark brown/black algal mats or water in this area.

“No one should drink the water from the river at any time, even after boiling the water as it does not remove the toxin, therefore, should not be consumed,” Dr Pink said.

Pets should be taken to a vet immediately if they are showing signs of illness after coming into contact with algal mats.

Environment Canterbury is monitoring the sites, and the public will be advised of any changes in water quality.