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Waikato Shallow Lakes Cyanobacterial Update Warning Lifted For Lake Kainui

Fuseworks Media
Fuseworks Media

6 April 2009 - The cyanobacterial health warning has been lifted for Lake Kainui following the latest monitoring results from the six Waikato shallow lakes that are routinely tested.

Warnings remain in place for Waahi, Waikare, Whangape and Ngaroto lakes.

Meanwhile, Lake Kainui's cell count has been below the warning level of 15,000 cells/ml for the last two samples, and the cells present are almost entirely single species, rather than a mixture of species," said Waikato District Health Board's Population Health medical officer of health Dell Hood.

"It is possible the warning may need to be reinstated if the current calm sunny weather continues."

Dr Hood said Waikato shallow lake users should always avoid contact with water which looks cloudy green or brown, or has scum forming even when there is no warning in place.

"In Kainui, it is quite possible that some areas of the lake will still have a cell count above the warning level, so users are warned to be cautious in using this lake particularly if children are likely to be in the water.

"Most lakes are not tested, and although cooler weather and shorter daylight hours generally decrease the growth of algae, the results of the testing over the last two-and-a-half years have been quite unpredictable.

"Users must consider the possibility of cyanobacterial blooms in any water body before they use it - at any time of year." Dr Hood also reminds the public that test results should be used for general guidance only, as cyanobacteria and their toxins will not be evenly spread through any lake and may be concentrated in some areas by wind and water movements.

"During blooms, lakes should not be used for any activity which involves skin contact with the water," she said.

"If people choose to do this, they should shower and change their clothing as soon as possible afterwards, even if no symptoms are noticeable."

Swallowing water from lakes affected by blooms should also be avoided.

While not everyone will be affected; for some, the risks include rash, skin and eye irritation, allergy symptoms such as hayfever and asthma and possibly stomach upsets such as diarrhoea and vomiting.

These effects may not appear until some time after contact with the affected water.

Waikato DHB's Population Health would like to be informed about health problems which develop after exposure to any of the Waikato lakes.

This allows recording of location, time, the activity taking place and length of time the problem lasted. Follow up testing may be done, depending on the situation.

"Up-to-date information on cyanobacterial cell counts is available from local councils and Environment Waikato. The Environment Waikato website: also has up to date results.

Health advice is available from Population Health (07) 839 8899 in and out of hours.

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