MEDIA RELEASE

Health warning issued for Te Wairewa/ Lake Forsyth

February 16, 2015

The Community and Public Health division of Canterbury District Health Board has issued a health warning after potentially toxic blue-green algae (planktonic cyanobacteria) was found in Te Wairewa/Lake Forsyth.

People and animals, particularly dogs, should avoid Te Wairewa/Lake Forsyth until the health warning has been lifted.

The type of cyanobacteria currently present in high concentrations is both Anabaena and Nodularia. These species form a thick green colouration to the water and often produce scums on the water surface.

Dr Alistair Humphrey, Canterbury Medical Officer of Health, says the algal bloom can produce toxins harmful to humans and animals.

“People should avoid contact with the water until further notice,” Dr Humphrey says.

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 and please let your doctor know if you have had contact with the lake water,” he says.

No one should drink the water from the lake at any time. Boiling the water does not remove the toxin.

“Animals that show signs of illness after coming into contact with lake water should be taken to a vet immediately.”

Avoid eating fish and shellfish as they can concentrate toxins.

“If fish are eaten, remove the gut and liver and wash in clean water.”

Environment Canterbury will monitor the lake weekly and the public will be advised of any changes that are of public health significance.

Facts about cyanobacteria:

• The algae occur naturally but can increase rapidly during warmer months

• Nutrient overload, especially nitrate and phosphorous levels, can contribute to the risk associated with the development of toxic algae blooms in lakes

• 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.

ENDS

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