Health warning removed for algal blooms in the Hurunui River at State Highway 7

The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health warnings issued for the Hurunui River at State Highway 7
Recent cyanobacteria surveying of the water in the Hurunui River has shown the quantity of potentially toxic blue-green algae (benthic cyanobacteria) in the river has decreased and are now below the levels that are of concern to public health.

Dr Ramon Pink, Canterbury Medical Officer of Health, says Environment Canterbury's routine monitoring of rivers in the Canterbury region has been completed for this summer season.

"It will resume again next summer when there is increased likelihood of cyanobacteria growth," Dr Pink says.

"The public is however reminded that there are still some lakes where warnings remain in place due to algal blooms."

The warnings remain in place at the following waterways due to ongoing algal blooms;

• Lake Ellesmere (Te Roto o Waihora)
• Lake Forsyth (Te Roto o Wairewa)
• Lake Pegasus

Facts about cyanobacteria:

• Appears as dark brown/black mats attached to rocks along the riverbed.
• The algae occur naturally but can increase rapidly during warmer months.
• It often has a strong musty smell and algal toxin concentrations can vary over short periods with changing environmental conditions.
• Although high river levels will remove the algal bloom, detached mats can accumulate along the shore and increase the risk of exposure to toxins.
• If a health warning is in place avoid contact with the water.
• Although district or city councils may place warning signs, these may not be seen at the numerous river access points, hence the need for people/ dog-walkers to treat every low-flowing river cautiously.

For further information visit

Or contact Community and Public Health on (03) 364 1777.

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