Health Warning Lifted For Algal Bloom At The South Bank Tributary Of The Waiau River Above Waiau Bridge

Health New Zealand – Te Whatu Ora has lifted its algal
bloom health warning issued for the South Bank Tributary of
the Waiau River above Waiau Bridge.

Recent
cyanobacteria surveys of the South Bank Tributary of the
Waiau River above Waiau Bridge has shown the cover of
potentially toxic algae (benthic cyanobacteria) in the river
has reduced and is now below levels that are of concern to
public health.

Dr Cheryl Brunton, Medical Officer of
Health for the National Public Health Service, says
Environment Canterbury’s monitoring of South Bank
Tributary of the Waiau River above Waiau Bridge has now
ceased and 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.

· A low cover of the algae can occur
naturally but can increase rapidly during warmer months.
Algal blooms are influenced by a combination of available
nutrients in the water and sediments (such as nitrogen and
phosphorus), a sustained period of low and stable flows, and
favourable weather conditions (e.g., increased temperature,
calm days).

· It often has a strong musty smell and
algal toxin concentrations can vary over short
periods.

· 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
details visit: https://www.lawa.org.nz/explore-data/canterbury-region/

Or
contact Te Mana Ora | Community and Public Health on (03)
364 1777:

https://www.cph.co.nz/your-health/recreational-water/

For
more information about Mahinga Kai:

https://www.cph.co.nz/wp-content/uploads/saf0112.pdf

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