Media information For immediate release
Date: 1 December
2009
Waikato Shallow Lakes Cyanobacterial Warning Update
Health warnings now in place for Lakes Waikare and Waahi
Recent cyanobacterial testing carried out on the six Waikato monitored lakes have started to show rises in cyanobacterial cell counts.
This was expected as the weather warms and days lengthen, says Waikato District Health Board medical officer of health Dell Hood.
The existing long-standing health warning for Waikare remains in place, and Waahi also now has a cell count well above the 15,000 cells/ml health warning level.
Lakes Kainui, Whangape, Hakanoa and Ngaroto do not currently have health warnings attached to them but it is likely that more warnings will be put in place after the next monitoring results are available.
Summer cyanobacterial testing is now back to a monthly schedule.
"Due to recent good weather, the cell counts could rise very quickly before the next results are known," said Dr Hood.
"Waikato shallow lake users should always avoid contact with water which looks cloudy green or brown, or has scum forming even when there is no warning in place."
Both Kainui and Ngaroto have cell counts approaching the warning level and it is quite possible that in some areas of these lakes, the cell count is already over 15,000 cells/ml.
Users are warned to be cautious in using these lakes; particularly children.
"Most lakes are not tested, and cell counts are likely to be rising in all of them as summer arrives," said Dr Hood.
She reminds the public that 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.
"During blooms, lakes should not be used for any activity which involves skin contact with the water," she said.
"If people choose to do this, they should shower and change their clothing as soon as possible afterwards, even if there are no noticeable symptoms."
Swallowing water from lakes affected by blooms should also be avoided.
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.
Population Health would like to know about health problems which develop after exposure to any of the Waikato lakes.
This allows location, time, the activity taking place and length of time the problem lasted, to be recorded. Follow-up testing may also be carried out.
Up-to-date information on cyanobacterial cell counts is available from local councils and Environment Waikato.
The Environment Waikato website:
http://www.ew.govt.nz/Environmental-information/Rivers-lakes-and-wetlands/healthyrivers/Waikato-River/Algal-Blooms-in-the-Waikato-region/#Heading4 has up-to-date results.
ENDS