Health warning at Pegasus Lake lifted

Tuesday April 19, 2016

The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health warning issued at Pegasus Lake. This was issued on 24 February 2016.

Recent water testing at Pegasus has shown the quantity of potentially toxic blue-green algae (planktonic cyanobacteria) in the lake has decreased and concentrations are now below the levels that are of concern to public health.

Dr Ramon Pink, Canterbury Medical Officer of Health, says as we move into winter there is a decreased chance of the toxic algae returning until the warmer months. 

"People are reminded to be aware of the signs of the presence of cyanobacteria in the lake as the monitoring frequency has now reduced from weekly to monthly," 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.
  • If a warning is in place, people and animals should not drink the water from the lake at any time, even boiled water.
  • Exposure to an algal bloom can 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 lake water when there is a health warning in place.

​For more information visit Environment Canterbury's website. Or contact Community and Public Health on (03) 364 1777.

Page last reviewed: 19 April 2016
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