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Urgent Public Information: Horizons Finds Cyanobacteria In Rivers

Fuseworks Media
Fuseworks Media
Urgent Public Information: Horizons Finds Cyanobacteria In Rivers

Horizons Regional Council says potentially toxic cyanobacteria, or blue/green algae, is becoming a problem as water levels drop in the region's rivers and streams.

Environmental scientist Kate McArthur said Horizons science and hydrology staff had found significant growths of the cyanobacteria Phormidium sp. in the upper Manawatu River and some tributaries.

She urged people to stay out of the water in areas showing obvious signs of the slimy black substance, which tends to occur on the stony beds or beaches of shallow parts of rivers and streams. Dog owners should be particularly wary and stop dogs from scavenging on river beaches.

"These growths are not always toxic but have been responsible for the deaths of dogs in many parts of the country in the past few years, and may cause skin irritation for people who come into contact with them," said Ms McArthur. "We have confirmed their presence in several rivers and streams to the east of the ranges, and it is highly likely that they are also present in areas of the lower Manawatu, Mangatainoka and other rivers throughout the region, though results from toxicity testing are not yet completed."

She said Horizons staff were monitoring the growth of cyanobacteria at selected sites and were sending samples to be tested for toxicity by specialists at the Cawthron Institute in Nelson.

The growths were likely to remain until significant rainfall caused water levels to rise.

"Dog owners should be particularly careful to keep their pets away from areas with obvious growths," said Ms McArthur. "Anyone with queries about possible growths should call Horizons on freephone 0508 800 800."

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