Health warning removed for algal bloom at Te Waihora/Lake Ellesmere.
The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health
warning issued at Te Waihora/Lake Ellesmere. This was issued on 4 February 2014.
Recent water testing at Te Waihora/Lake Ellesmere 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.
Canterbury Medical Officer of Health Dr Alistair Humphrey says Environment Canterbury’s sampling of Te Waihora/Lake
Ellesmere will continue on a monthly basis. “The public will be informed when testing shows that concentrations have
increased and there is a risk to public health again, which is likely to be in the summer months,” Dr Humphrey 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.
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