Health Warning – Algal Bloom in Lake Hood

Te Mana Ora | Community and Public Health has issued a
health warning after potentially toxic blue-green algae
(planktonic cyanobacteria) was found in Lake
Hood.

People should avoid the lake and animals,
particularly dogs, should not be allowed near the water
until the health warning has been lifted.

The type of
cyanobacteria that is currently present is Dolichospermum
(formerly called Anabaena) which can be present as green
globules floating in the water column or form surface scums
or sheens.

Dr Cheryl Brunton, Medical Officer of
Health for Te Mana Ora, National Public Health Service, says
the algal bloom can produce toxins harmful to humans and
animals.

“People should avoid contact with the water
until further notice.”

“Exposure may cause skin
rashes, nausea, stomach cramps, tingling and numbness around
the mouth and fingertips. If you experience any of these
symptoms visit your doctor immediately and please let your
doctor know if you have had contact with the lake water”,
Dr Brunton says.

No one should drink the water from
the lake at any time. Boiling the water does not remove the
toxin.

Animals that show signs of illness after coming
into contact with algal mats or scums should be taken to a
vet immediately.

Fish and shellfish can concentrate
toxins and their consumption should be avoided. If fish are
eaten, remove the gut and liver and wash in clean
water.

Further information on gathering Mahinga Kai
can be obtained below.

“When a bloom of potentially
toxic cyanobacteria is present in a lake, there is a
possibility of cyanobacteria and toxins being transported
downstream.

“People are advised to avoid contact
with the downstream water bodies,” says Dr
Brunton.

Environment Canterbury monitors the lake
weekly during summer and the public will be advised of any
changes in water quality that are of public health
significance.

Facts about cyanobacteria

·
Cyanobacteria occur naturally but can increase rapidly
during warmer months.

· Algal blooms are caused by a
combination of nutrients in the water (such as nitrogen and
phosphorus), and favourable weather conditions (e.g.,
increased temperature, calm days).

· If the water is
cloudy, discoloured, or has small globules suspended in it,
avoid all contact.

· Not all cyanobacterial blooms
are visible to the naked eye and toxins can persist after
the blooms disappear.

· Cyanobacterial concentrations
can change quickly with changing environmental conditions
(e.g., wind). If a health warning is in place avoid contact
with the water.

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

Or
contact Te Mana Ora 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

For
further information,
contact:

communications@cdhb.health.nz

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