Health warning removed for algal bloom in the Hurunui River at State Highway 7 near the Balmoral Swimming Hole
The Community and Public Health division of the Canterbury District Health Board has lifted its algal bloom health
warning issued along the Hurunui River at State Highway 7 near the Balmoral Swimming Hole.
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 the cover is now below the levels that are of concern to
public health.
Medical Officer of Health Dr Cheryl Brunton says Environment Canterbury’s surveying of the Hurunui River will continue
to the end of this summer and then 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, hence the need for people/ dog-walkers to treat every low-flowing river cautiously.
For further information visit https://www.ecan.govt.nz/your-region/your-environment/water/swimming-water-quality/
Or contact Community and Public Health on (03) 364 1777.