KEY POINTS:
Councils and public health officials in many parts of the country are warning householders and holidaymakers to be wary of toxins from algae blooms spreading in lowland lakes and rivers.
Around the capital, the Wellington Regional Council has warned the dry warm weather is exposing algal mats on riverbanks and in shallows, where they could affect animals and humans.
People swimming or taking water for humans or animals have been urged to avoid any contact with the algae mats, which are usually dark green/brown in colour.
Similar warnings have been made for the lower Rangitaiki River downstream from Te Teko, and at Whakatane, Toi Te Ora medical officer of health Jim Millar said the cyanobacterial toxins may have already killed a dog that had been swimming in the river.
Earlier, health warnings were issued in the Waikato for Lakes Hakanoa, Waahi, Ngaroto, Waikare, Whangape and Kainui, where the cyanobacteria that make up blue-green blooms turn the water into an algal soup.
"Most lakes are not tested, and water users must consider the possibility of cyanobacterial blooms in any water body before they use it," said Waikato medical officer of health Dell Hood.
People should always avoid contact with water that looked cloudy green or brown, or had scum forming, even when there was no warning in place.
Dr Barbara Dolamore, a Christchurch Polytechnic Institute of Technology (CPIT) senior lecturer in biochemistry and molecular biology, who has been carrying out a longterm study of the environmental effects of toxic cyanobacteria, said algae had killed dogs, sheep and cattle that drank from Lake Forsyth/Wairewa on Banks Peninsula.
Even eating eels from the lake could be dangerous. Dr Dolamore said that since the nodularin toxin was not destroyed by cooking accumulation of the toxin in fish could also be hazardous to people's health.
- NZPA
