Toxic algae warning in Hamilton

Lake Rotoroa, yesterday during the 'Balloons over Waikato 2011' festival. Photo / Christine Cornege

Hamilton residents walking their dogs should be cautious of blue-green algae scum along the northern shore of Lake Rotoroa.

The Waikato District Health Board has issued health warnings for five lakes outside Hamilton after finding high levels of cyanobacterial cells, also known as blue green algae, in the water.

Waahi has a new warning, and existing warnings remain in place for Ngaroto, Whangape, Hakanoa and Waikare lakes.

The health board said Lake Rotoroa, which is Hamilton's largest lake, had become a more significant health risk since a health warning was issued in mid-February.

Blue-green algae have since formed scum due to the wind, particularly around the northern shores of the lake, it said.

Contact with the scum around the lake was hazardous, especially to children and dogs. Skin should be rinsed clean and clothing changed as soon as possible if anyone came into contact with it.

During blooms, lakes should not be used for any activity.

The risks include rash, skin and eye irritation, allergy symptoms such as hayfever and asthma and possibly diarrhoea and vomiting.

- NZPA