People and animals, particularly dogs, are being warned to avoid the area of the Waimakariri River near State Highway 1 and Main North Road bridges because of a potentially toxic algal bloom.
Canterbury District Health Board’s Community and Public Health unit have issued a health warning after finding benthic cyanobacteria, a potentially toxic blue-green algae, in the Otukaikino/Waimakariri confluence.
Dr Ramon Pink, Canterbury Medical Officer of Health, says the algae look like dark brown to black mats and can produce toxins harmful to people and animals.
“Exposure may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips,” Dr Pink says.
“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 from the river, it does not remove the toxin therefore should not be consumed,” Dr Pink says.
Pets should be taken to a vet immediately if they are showing signs of illness after coming into contact with algal mats.
People and animals should remain out of the waterways until the warnings have been lifted.
Environment Canterbury is monitoring the site and the public will be advised of any changes in water quality.
“The phormidium is growing where nutrient rich water from the Otukaikino is running across the cobbled bed of the Waimakariri and slowly mixing with the low nutrient water of the Waimakariri. We expect it will clear when there is a substantial flow in the Waimakariri,” says Dr Tim Davie, Enviornment Canterbury’s Chief Scientist.
Facts about cyanobacteria: