A health warning is in place for Lake Okaro after routine summer monitoring results provided by Bay of Plenty Regional Council confirmed the presence of potentially toxic blue-green algae blooms.

The warning was issued by Toi te Ora Public Health, endorsed by its medical officer of health Dr Phil Shoemack.

Image: Google Earth.

'Blue-green algae are present in Lake Okaro at levels that may result in adverse health effects and so it is advisable for people to avoid contact with the water.”

Contact with algal blooms can trigger asthma and hayfever attacks, as well as skin rashes, stomach upsets, and neurological effects such as tingling around the mouth, headaches, breathing difficulties and visual problems.

Lake Okaro, near Rainbow Mountain, about 20km to the south of Rotorua, is prone to blooms, some of which persist for several months.

'Ongoing weekly monitoring of the main lakes and rivers in the Bay of Plenty will continue throughout the summer and the public will be advised where high levels of blue-green algae are detected” says Phil.

'However, in the right conditions, algal blooms can develop rapidly and unpredictably, so wherever you are swimming this summer, it is important to ‘look before you leap' and make your own judgement of the water – if in doubt stay out.”

If the water has a musty smell, if it appears murky with a blue or greenish tinge, or if there is a scum on the surface, people should avoid entering the water.

Pets should also be kept away from areas where blooms are present.