Health warning removed for algal bloom at Te Wairewa / Lake Forsyth

Wednesday January 25, 2012

The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health warning, issued on November 3, 2011, at Te Wairewa/Lake Forsyth.
Recent water testing at Te Wairewa/Lake Forsyth has shown the quantity of potentially toxic algae (planktonic cyanobacteria) in the lake has decreased and concentrations are now below the levels that are of concern to public health
Canterbury Medical Officer of Health Dr Ramon Pink says Environment Canterbury’s sampling of Lake Te Wairewa/Lake Forsyth will continue throughout the summer.
“The public will be informed if testing shows that concentrations have increased and there is a risk to public health again,” Dr Pink says.
A warning still remains in place at Te Waihora/Lake Ellesmere.
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.
Or contact Community and Public Health on (03) 364 1777.

Page last reviewed: 23 July 2013