Source: Waikato District Health Board
The Public Health warning issued on 23 January 2023 for Lake Ngā Roto has now been lifted, after subsequent tests showed that cyanobacterial levels are once again below the warning level. Lakes, Whangape, Waikare, and Kainui continue to have a cyanobacterial health warning in place.
Dr Richard Wall, 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.
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.
Dog owners should prevent their dogs from drinking or swimming in the water, as dogs are particularly sensitive to cyanobacteria.
Cyanobacteria can produce toxins harmful to the health of humans and animals exposed to or swallowing the water where the algae are growing.
Te Whatu Ora Public Health Service for Waikato would like to be informed about health problems that develop after exposure to any of the Waikato lakes can be contacted on (07) 838 2569.
Up-to-date information on cyanobacterial cell counts is available from the Land Air Water Aotearoa (LAWA) website at https://www.lawa.org.nz/explore-data/waikato-region/
