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Health warning issued for Lake Ngaroto and Lake Waikare

Fuseworks Media
Fuseworks Media

A new health warning has been issued today for Lake Ngaroto, due to a rise in cyanobacteria levels. Lake Waikare also continues to have a cyanobacterial health warning in place. Waikato Regional Council has recently increased the number of lakes it regularly tested for cyanobacteria. Lakes’ Kainui, Puketirini, Te Koutu, Rotokauri, Whangape, Waahi, and Hakanoa, the others lake that are tested regularly by Regional Council, currently remain below the warning level for cyanobacteria.

Waikato DHB’s medical officer of health Dr Richard Wall recommends that where cyanobacteria health warnings are in place, lakes should not be used for any activity that involves skin contact with the affected water.

"Swallowing water from lakes affected by blooms should also be avoided," said Dr Wall.

"Scums are a particular risk because they contain a high level of toxins. If contact with scum does occur, skin should be rinsed clean and clothing changed as soon as possible. This warning is particularly important for children."

"If people still choose to use the lakes when warnings are in place, or any other lake where there are visible changes to water colour, they should shower and change their clothing as soon as possible afterwards, even if no symptoms are noticeable," he said.

Symptoms include rash, skin and eye irritation; allergy symptoms such as hayfever and asthma; and possibly stomach upsets including diarrhoea and vomiting.

These symptoms may not appear until sometime after contact with the affected water. Long-term exposure to cyanobacterial toxins may cause additional health risks.

The cyanobacteria biovolume has risen to 3 mm3/L at Lake Ngaroto. Biovolume is the measure used to decide when a health warning should be issued, with the cut-off value for a health warning is set at 1.8mm3/L.

Cyanobacteria are a form of algae which can produce toxins harmful to the health of humans and animals exposed to or swallowing the water where the algae are growing.

Waikato DHB’s Public Health Unit would like to be informed about health problems that develop after exposure to any of the Waikato lakes. Health advice is also available from the Public Health Unit on (07) 838 2569.

Up-to-date information on cyanobacterial cell counts is available from local councils and Waikato Regional Council.

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