|News and media|
Cyanobacterial warning lifted from Lake Waahi, no health warning for Lake Rotoroa in HamiltonThe health warning has now been lifted for Lake Waahi, but warnings remain in place for the other regularly tested lakes outside Hamilton. These lakes are Ngaroto Hakanoa, Waikare, and Whangape.
Lake Rotoroa in Hamilton also has no health warning at present.
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, and it is likely that warnings may need to be reinstated for both Waahi and Rotoroa if there is sustained warm, dry weather.
During blooms, lakes should not be used for any activity which involves skin contact with the water,” said medical officer of health Dr Dell Hood. 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.
Swallowing water from lakes affected by blooms should also be avoided.
“If people still choose to use the lakes when warnings are in place, they should shower and change their clothing as soon as possible afterwards, even if no symptoms are noticeable,” said Dr Hood.
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.
The Waikato DHB Population Health Service 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: http://www.waikatoregion.govt.nz/Environment/Natural-resources/Water/Rivers/Waikato-River/Algal-Blooms-in-the-Waikato-region/
Health advice is available from the Population Health Service (07) 839 8899 in and out of hours.
Date: 3 February 2012
Mary Anne Gill
Waikato District Health Board
021 705 213