Health warning lifted for the Selwyn River at Whitecliffs Domain
The Community and Public
Health division of the Canterbury District Health Board has
lifted its algal bloom health warning issued along the
Selwyn/Waikirikiri River at Whitecliffs Domain. This warning
was issued on 21 December 2017.
Recent water testing at Selwyn/Waikirikiri River has shown the quantity of potentially toxic blue-green algae (benthic cyanobacteria) in the river has decreased and cover is now below the levels that are of concern to public health.
Canterbury Medical Officer of Health Dr Alistair Humphrey says Environment Canterbury’s sampling of the Selwyn/Waikirikiri River will continue to the end of this summer.
The algal bloom warning remains in place for the Selwyn/Waikirikiri River at Glentunnel and at Chamberlains Ford.
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.
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