Health warning issued for a North Canterbury lagoon

Thursday September 11, 2014

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, 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," Dr Pink says.

The type of cyanobacteria currently present in high concentrations is Anabaena, 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 lagoon at any time, even after it's been boiled as it does not remove the toxin.

"Animals showing signs of illness after coming into contact with the water, should be taken to a vet immediately," Dr Pink says.

Environment Canterbury will monitor the lagoon fortnightly 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.


For further information visit http://ecan.govt.nz/services/online-services/monitoring/swimming-water-quality/Pages/lake-warnings.aspx
Or contact Community and Public Health on (03) 364 1777.

Page last reviewed: 11 September 2014
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