Source: Waikato District Health Board
CYANOBACTERIAL WARNING UPDATE: Health warning lifted for Lake Ngā Roto, and remains in place for Lakes Rotoroa (Hamilton Lake), Waikare, Hakanoa, Rotokauri, Whangape and Kainui.
The Public Health warning issued on 7th November 2023 for Lake Ngā Roto has now been lifted after subsequent tests showed that cyanobacterial levels are below the warning level. Lakes Rotoroa (Hamilton Lake), Waikare, Hakanoa, Rotokauri, Whangape and Kainui continue to have a cyanobacterial health warning in place.
Dr Richard Wall, Health New Zealand – 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 Wall.
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,” he said.
Dog owners should prevent their dogs from drinking or swimming in the water, as dogs are particularly sensitive to cyanobacteria.
Health NZ 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 by visiting the Land Air Water Aotearoa (LAWA) website at https://www.lawa.org.nz/explore-data/waikato-region/
