News Video | Policy | GPs | Hospitals | Medical | Mental Health | Welfare | Search


Cyanobacterial Warning Update

Media Release

Date: 5 December 2012

Cyanobacterial Warning Update

Warmer Weather Brings A New Health Warning

A cyanobacterial bloom or sudden massive episode of growth has occurred in Lake Whangape, which now joins Waikare in having a cyanobacterial health warning in place. This is an anticipated seasonal event following on from longer hours of daylight and warmer weather.

The five other lakes which are routinely tested remain at acceptable levels of cyanobacteria, and do not have health warnings. This includes Hamilton City’s Rotoroa (Hamilton Lake.) However, it is likely that more health warnings will be required as summer progresses.

Waikato Regional Council is no longer routinely testing Lake Kainui but caution is always advised for users of this lake, because of its history of cyanobacterial blooms.

As always, these test results should be used for general guidance only, as cyanobacteria and their toxins will not be evenly spread through any lake and may be concentrated in some areas by wind and water movements. Cyanobacterial blooms can happen very quickly when conditions for growth are favourable.

Waikato DHB medical officer of health Dell Hood said during blooms, lakes should not be used for any activity which involves skin contact with the water.

"Scums are a particular risk and contact with scums should be avoided. If contact does occur, skin should be rinsed clean and clothing changed as soon as possible. Because of their small size, this warning is particularly important for children," said Dr Hood.

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

“If people still choose to use the lakes when warnings are in place, or 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.”

While not everyone will be affected, for some, the risks include rash, skin and eye irritation, allergy symptoms such as hayfever and asthma and possibly stomach upsets such as diarrhoea and vomiting.

These effects may not appear until some time after contact with the affected water. Long term exposure to cyanobacterial toxins may bring additional health risks. Scums on any lake are likely to contain high levels of toxin.

Waikato DHB's Population Health would like to be informed about health problems which develop after exposure to any of the Waikato lakes.

“Up-to-date information on cyanobacterial cell counts is available from local councils and Waikato Regional Council. The Waikato Regional Council website:

Health advice is available from Population Health (07) 839 8899 in and out of hours.


About Waikato District Health Board and Health Waikato:

Waikato DHB is responsible for planning, funding and providing quality health and disability support services for the 372,865 people living in the Waikato DHB region. It has an annual turnover of $1.2 billion and employs more than 6000 people.

Health Waikato is the DHB’s main provider of hospital and health services with an annual budget of more than $701 million and 5238 staff. It has six groups across five hospital sites, three primary birthing units, two continuing care facilities and 20 community bases offering a comprehensive range of primary, secondary and tertiary health services.

A wide range of independent providers deliver other Waikato DHB-funded health services - including primary health, pharmacies and community laboratories.

Check out our media releases on


© Scoop Media

Culture Headlines | Health Headlines | Education Headlines


Howard Davis Review: A Bigger Splash - Te Papa Celebrates Twenty Years

Considering the available resources, this is a decidedly hit-and-miss affair, mainly due to some highly questionable curatorial decisions. In their overweening wish to "push boundaries," Charlotte Davy and Megan Tamati-Quennell have made a number of serious miscalculations by ignoring a basic rule - keep it simple. More>>

Howard Davis Review: Smelling the Merchandise - The Death of Stalin

Having satirised British democracy with such devastating effect, Armando Iannucci has now turned his lens on the dangers inherent in Soviet authoritarianism. Every gag is girdled with fear and the bleak humour is so pitch black it could only have been pumped from deep underground. More>>

Howard Davis Review: The Creole Stylings of Cécile McLorin Salvant

"You only get a singer like this once in a generation or two," commented Wynton Marsalis, who has repeatedly hired her to front his jazz orchestra and mounted a 25 foot high portrait of her on the exterior of Lincoln Center. “She radiates authority. She has poise, elegance, soul, humour, sensuality, power, virtuosity, range, insight, intelligence, depth, and grace.” More>>

Max Rashbrooke Review: The King's Singers and Voices New Zealand

To be good at one thing is impressive; to be so versatile across a range of genres is truly exceptional. The latest incarnation of this six-strong male singing group includes Kiwi Christopher Bruerton, and it was a delight to hear him sing the solo on the achingly beautiful My Love Is like a Red, Red Rose. More>>



  • Wellington
  • Christchurch
  • Auckland