Toxic algae warnings lifted at Ashburton River bridge site, near SH1

Health warnings relating to a potentially toxic algae for the Ashburton River, near State Highway 1, have been lifted after monitoring by Environment Canterbury (ECan) shows cyanobacteria is no longer at toxic levels.

Ashburton District Council will today be removing the warning signs advising of the presence of the toxic algae after being informed by ECan it is safe to do so.

On December 25 last year Council received notice from ECan that monitoring of water quality at the Ashburton River bridge site showed increased levels of toxic algae (cyanobacteria) which triggers warnings to be issued.

Environmental Monitoring Manager Rick Catchpowle says ECan's monitoring has produced two consecutive survey results below the 20% alert trigger value and the algae mats are no longer detaching.

"While the reduced algae levels means the area is now safe for dogs, the water quality is not considered suitable for human recreation and bathing due to the health risk from bacteria present in the water."

The health warning signs advising people against swimming at the site remain in place.

Cyanobacteria occur naturally and can increase rapidly during warmer periods.

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Page reviewed: 20 Mar 2015 1:26pm