Health Warning Removed for Algal Bloom on the Selwyn River

The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health warning issued along the Selwyn River. This was issued on February 2, 2011.

Recent surveys at Whitecliffs and Glenntunnel on the Selwyn River have shown that the quantity of potentially toxic blue-green algae (benthic cyanobacteria) in the river has decreased to below levels that are of concern to public health.

Canterbury Medical Officer of Health Dr Ramon Pink says Environment Canterbury’s sampling will resume next summer when there is increased likelihood of cyanobacteria growth.

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. It is important to treat every low-flowing river cautiously, especially keeping dogs away as the algae can be particularly harmful to them.

For further information visit http://ecan.govt.nz/services/online-services/monitoring/swimming-water-quality/Pages/river-warnings.aspx

ENDS

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