Media Release: 24 January 2014
Health warning for North Canterbury lagoon
The Community and Public Health division of Canterbury District Health Board has issued a health warning for a North
Canterbury lagoon after potentially toxic blue-green algae (planktonic cyanobacteria) was found.
Dr Ramon Pink, Canterbury Medical Officer of Health, says people and animals, should avoid contact with the water at St
Annes/ Mata Kopae Lagoon, a wildlife sanctuary near Cheviot, until the health warning has been lifted.
“The algal bloom can produce toxins harmful to humans and animals. Dogs are particularly susceptible to the health
risks. Fortunately they are prohibited in this wildlife sanctuary.”
The type of cyanobacteria that is currently present in high concentrations isAnabaena, which visually gives a green “soupy” appearance to the water.
“People should avoid contact with the water until further notice. 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 and please let your doctor know if you have had
contact with the lake water.”
No one should drink the water from the lake at any time, even after it’s been boiled as it does not remove the toxin.
“Animals that show signs of illness after coming into contact with the water should be taken to a vet immediately,” Dr
“Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut
and liver and wash in clean water.”
Environment Canterbury will monitor the lagoon weekly during the bloom and the public will be advised of any changes in
water quality that are of public health significance, Dr Pink says.
Facts about cyanobacteria:
> The algae occur naturally but can increase rapidly during warmer months.
> If the water is cloudy, discoloured, or has small globules suspended in it, avoid all contact.
> Not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the blooms disappear.
> Cyanobacterial concentrations can change quickly with changing environmental conditions (e.g. wind). If a health
warning is in place avoid contact with the water.