Health warning lifted for Lake Rotoroa / Hamilton Lake but still in place for some Waikato lakes.

A health warning for Lake Rotoroa has been lifted.

The health warning that was placed in late August 2023 at Lake Rotoroa, has been lifted for recreational activities other than swimming with tests showing only low cyanotoxin levels.

People using the lake are advised to avoid any scum.

Dr Richard Wall, Te Whatu Ora Medical Officer of Health for Waikato said scums were a particular risk because they were likely to have a higher concentration of cyanobacteria. If contact with scum did occur, skin should be rinsed clean and clothing changed as soon as possible.

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 Wall recommended that where cyanobacteria health warnings were in place, lakes should not be used for any recreational activity that involved contact with the water.

“Swallowing water from lakes affected by blooms should also be avoided.”

Cyanobacteria can release toxins that can trigger asthma and hay fever symptoms and could cause skin rashes, stomach upsets, and in some cases neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.

Those symptoms might not appear until some time after contact with the affected water.

“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.”

Dog owners should prevent their dogs from drinking or swimming in the water, as dogs were particularly sensitive to cyanobacteria.

Te Whatu Ora Public Health Unit for Waikato asks people to report any health problems that developed after exposure to any of Waikato lakes.

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