Source: Waikato District Health Board
CYANOBACTERIAL WARNING UPDATE: Health warning lifted for Lake Rotoroa (Hamilton Lake) and remains in place for Lake Ngā Roto, Hakanoa, Waikare and Kainui.
The Public Health warning issued on 5 October 2023 for Lake Rotoroa (Hamilton Lake) has now been lifted, after subsequent tests showed that cyanobacterial levels to be once again below the warning level. Lakes Ngā Roto, Hakanoa, Waikare and Kainui continue to have a cyanobacterial health warning in place.
Waikato Regional Council monitors cyanobacteria levels at Lakes Kainui, Rotokauri, Ngā Roto, Puketirini, Waikare, Whangape, Hakanoa and Waahi.
Dr Felicity Dumble, Te Whatu Ora Medical Officer of Health for Waikato 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 Dumble.
Cyanobacteria can release toxins which can trigger asthma and hayfever symptoms, and can cause skin rashes, stomach upsets, and in some cases neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.
These symptoms may not appear until some time after contact with the affected water.
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 do come into contact with the lake 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,” she said.
Dog owners should prevent their dogs from drinking or swimming in the water, as dogs are particularly sensitive to cyanobacteria.
Te Whatu Ora Public Health Unit for Waikato would like to be informed about health problems that develop after exposure to any of the Waikato lakes.
Up-to-date information on cyanobacterial cell counts is available from local councils, Waikato Regional Council or by visiting the Land Air Water Aotearoa (LAWA) website at https://www.lawa.org.nz/explore-data/waikato-region/
