February 18, 2013
Health Warning – Algal Bloom in Hurunui River at SH1
The Community and Public Health division of the Canterbury District Health Board have issued a health warning after
potentially toxic blue-green algae (benthic cyanobacteria) were found in Hurunui River at State Highway 1.
People and animals, particularly dogs, should avoid the Hurunui River at State Highway 1 until the health warning has
been lifted.
Canterbury Medical Officer of Health Dr Ramon Pink says that the algae looks like dark brown to black mats and can
produce toxins harmful to people and animals.
“Exposure may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips,” Dr Pink
says.
“If you experience any of these symptoms, visit your doctor immediately, also let your doctor know if you’ve had contact
with dark brown/black algal mats or water in this area.”
“No one should drink the water from the river at any time. Importantly, boiling water from the river does not remove the
toxin.”
Animals that show signs of illness after coming into contact with algal mats should be taken to a vet immediately.
Environment Canterbury is monitoring the sites and the public will be advised of any changes in water quality.
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 http://ecan.govt.nz/services/online-services/monitoring/swimming-water-quality/Pages/river-warnings.aspx
Or contact Community and Public Health on (03) 364 1777.
ENDS