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Health warning issued for Lake Whangape, removed at Lake Kainui

Fuseworks Media
Fuseworks Media

A new health warning has been issued today for Lake Whangape, due to a rise in cyanobacteria levels. The health warning issued in 15th January 2019 for Lake Kainui, has now been lifted, after two consecutive tests showed cyanobacterial levels to be once again below the warning level. 

Lakes’ Ngaroto and Waikare continue to have a cyanobacterial health warning in place. Waikato Regional Council has recently increased the number of lakes it regularly tests for cyanobacteria. Lakes’ Puketirini, Te Koo utu, Rotokauri, Hakanoa and Waahi, the other lakes that are tested regularly by Waikato Regional Council, currently remain below the warning level for cyanobacteria.

Waikato DHB’s Medical Officer of Health Dr Richard Hoskins 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 Hoskins.

"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 some time after contact with the affected water. Long-term exposure to cyanobacterial toxins may cause additional health risks.

The cyanobacteria biovolume has risen to 38.6 mm3/L at Lake Whangape. Biovolume is the measure used to decide when a health warning should be issued, with the cut-off value for a health warning 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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