Lake health warning still in place
While a health warning for Waipa’s Lake Ngaroto has been lifted, Lake Waikare is still deemed as too toxic.
The health warning for Lake Ngaroto was issued in June after two consecutive tests showed cyanobacterial levels to be once again below the warning level.
However Lake Waikare continues to have a cyanobacterial health warning in place.
Waikato DHB medical officer of health Dr Richard Wall recommended that during blooms, like at Waikare, areas should not be used for any activity that involves skin contact with the affected water.
‘‘Scums are a particular risk because they contain a high level of toxins. If contact with scum does occur, skin should be rinsed clean and clothing changed as soon as possible. This warning is particularly important for children,’’ Wall said.
He said if people still choose to use the lakes when warnings are in place, they should shower and change clothing as soon as possible.
Symptoms include rash, skin and eye irritation; allergy symptoms such as hayfever and asthma; and possibly stomach upsets including diarrhoea and vomiting.
They may not appear until some time after contact with the affected water. Long-term exposure to cyanobacterial toxins may cause additional health risks.
Lake Waikare has been found to have a cyanobacteria biovolume of 5.1 mm3/L. Biovolume is the measure used to decide when a health warning should be issued, with the cutoff value for a health warning set at 1.8mm3/L.
Testing is carried out by Waikato Regional Council monthly during the warmer months, and every two months over winter. Lakes Hakanoa, Waahi and Whangape are also tested.