Cyanobacterial bloom found in Hawke’s Bay

15 September 2005

Be on the alert: cyanobacterial bloom found in Hawke’s Bay

Hawke’s Bay District Health Board’s (HBDHB) public health unit has issued a warning to the public to be aware of the potential dangers of cyanobacterial algal bloom.

A recent case where two dogs became temporarily paralysed after drinking water from a contaminated waterway on a private property at Poukawa, (near Te Hauke) south of Hastings, has lead to Hawke’s Bay Regional Council and Hastings District Council investigating the Poukawa Stream.

“While we don’t know exactly why this is occurring, cyanobacterial (formerly known as blue-green) bloom is becoming more common in New Zealand,” said Dr Caroline McElnay, medical officer of health for HBDHB. “Blooms like this are often triggered by fine, warm, settled weather.

“In this case, we know the area where the cyanobacteria was identified is not used for swimming or drinking water, so there is minimal risk to the public, however, it’s important that people are aware of its existence in Hawke’s Bay.

“This cyanobacterial bloom is not visible to the naked eye - it can be present in clean-looking, clear water. It’s naturally present in many waterways, but in low concentrations. It only becomes a problem, when levels increase or ‘bloom’. Cyanobacteria can cause offensive odours or taint drinking water due to the high levels of toxins.

“If you have any concerns about bad smells in any waterway, it’s wise not to drink the water, swim, take watercress or fish. Boiling water will not get rid of the toxins from cyanobacteria. As a rule, people should never take drinking water from standing water such as ponds, dams lakes and rivers, especially in low flow conditions.

Drinking water containing toxic cyanobacteria blooms can result in:
- Death of stock
- Liver complaints in humans
- Paralysis of skeletal and respiratory muscles
- Irregular breathing or twitching
- Weakness, vomiting, cold extremities, diarrhoea, heavy breathing and in rare cases death

Swimming or showering/bathing in waters containing toxic cyanobacteria blooms can result in:
- Severe dermatitis
- Burning or itching skin
- Red eyes & lips
- Sore throat
- Asthma symptoms
- Dizziness

The public health unit, in conjunction with Hawke’s Bay Regional Council and other Hawke’s Bay local authorities monitor popular beaches, lakes and rivers over the summer months. If cyanobacterial blooms are identified at unsafe levels, public warnings will be issued.

If anyone suspects a waterway has become contaminated, they should contact the Hawke’s Bay Regional Council and ask for the pollution control by phoning 0800 108 838.

ENDS

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