February 16, 2009
MEDIA STATEMENT

ECan steps up toxic river algae warnings

The death of a second dog at the weekend at Chamberlain’s Ford on the Selwyn River, Central Canterbury, has prompted an urgent warning to dog owners from Environment Canterbury. A dog died last week on the Ashley River/Rakahuri after licking the toxic black/brown algal mats (Phormidium).

This past weekend, Environment Canterbury’s Pollution Hotline staff were alerted to the dog death at Chamberlain’s Ford. At least two other dogs were taken to the vet having suffered seizures from the Selwyn River algae.

People, particularly families with children, are warned not to swim in any river with the black/brown algal mats nearby or on rocks as it may cause allergic reactions and skin disorders.

Last week Environment Canterbury (ECan) issued a general statement to all river users following the dog death in North Canterbury and after inspections at several rivers in South Canterbury also had shown small amounts of toxic algal mats on river rocks.

ECan staff also inspected the Selwyn River mid last week and observed few signs of Phormidium. However, rain at the end of the week may have washed the algae into Chamberlain’s Ford and other areas of the river popular with recreationalists.

“This highlights the uncertainty about being able to predict the risks to the community of this algae and the need to put out warnings at any locations that have Phormidium mats present,” said ECan water quality scientist Shirley Hayward. “At the same time, we can't inspect all reaches of every river, so we need to educate the community about what to look for and how to prevent themselves and their animals coming into contact with the algae. A safe area one day may not be a safe place to swim a day later.”

ECan is urging district councils to place signs warning of the algae, at least at the most popular recreational places.

“People are warned to look out for areas of rivers where dark brown/black mats of algae are growing or forming scums, and keep dogs out of these waters and avoid swimming. Dogs and stock should also be kept away from stagnant ponds, especially those which have bright green or red scums or have strong odours,” said Shirley Hayward.

Dr Alistair Humphrey, Medical Officer of Health, says people swimming in water with increased levels of algal bloom have been known to develop allergic reactions – asthma, eye irritations, rashes, blistering around the mouth and nose and gastro intestinal disorders including abdominal pain, cramps and diarrhoea.

The North Island has also had similar algal blooms in recent weeks, see:
www.horizons.govt.nz/ or www.gw.govt.nz/section2535.cfm

ENDS

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