Source: Waikato District Health Board
A health warning was placed in late August 2023 at Lake Rotoroa (Hamilton lake), and remains in place with more recent laboratory testing showing increasing levels of cyanobacteria. The warning signs at the lake will continue to show the ‘Alert’ warning until two consecutive samples show that the risk has decreased.
Lakes Hakanoa, Whangape, Waikare and Kainui continue to have a cyanobacterial health warning in place.
Cyanobacteria levels are regularly monitored at Lakes Rotoroa, Kainui, Rotokauri, Ngā Roto, Puketirini, Waikare, Whangape, Hakanoa and Waahi.
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 recreational activity that involves 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.
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.
