16 November 2005

Toxic algal bloom found in Hutt River

Pollution tests undertaken by the Cawthron Institute for Greater Wellington, have confirmed – the thick green-black slimy algae mat seen on rocks along the banks of the Hutt River is highly toxic and could be harmful to animals and humans.

Vets have reported seeing several sick dogs during the week after they had been walking along the Hutt River. It is believed the dogs have eaten algae. One dog has since died. Symptoms include shaking and convulsions.

The potentially toxic cyanobacteria Oscillatoria sp has been detected in high abundance and is thought to be the same species which was responsible for five dog deaths in the Waikanae River in the summer of 1998/99.

Nic Conland, Pollution Control Officer for Greater Wellington says low rainfall in recent weeks has reduced river flows. He says that as nutrient levels become more concentrated they create near perfect conditions for algal blooms. Nic reminds us that algal blooms are a natural occurrence and not all algae are toxic.

The Hutt City Council is erecting signs to warn people of the potential hazard of walking dogs along the river banks. His advice is for dog owners to keep clear of the Hutt River until further testing confirms the absence of algal toxins. “What is needed is a good downpour to remove algal growth. In the meantime if you see any algal blooms that may be suspicious contact your local council for advice.”

As ingestion of algal toxins may be harmful to humans, Regional Public Health Medical Officer of Health, Dr Margot McLean, advises that people should avoid contact with algal material on the banks of the Hutt River. In particular, parents or caregivers should supervise young children playing close to the river to ensure they do not touch or eat any algal material.

ENDS

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