Watch on for Algal Blooms
Media Release
29 January
2015
Watch on for Algal Blooms
http://www.hbrc.govt.nz/News-Events/Media-Releases/Pages/Watch-on-for-Algal-Blooms.aspx
The temperaturescurrent weather conditions, resulting in lower river flows and warmer water , increase the likelihood of algal blooms in Hawke’s Bay fresh waterways.
Hawke’s
Bay Regional Council and Hawke’s Bay District Health Board
remind people to take care around streams, rivers and lakes
as algal blooms can be toxic to humans and dogs.
HBRC
staff have not observed any cyanobacteria mats yet this
summer but are monitoring popular recreational sites on the
Ngaruroro, Tutaekuri and Tukituki rivers each
week.
Stephen Swabey, HBRC Science Manager says “Algal blooms occur in many of our rivers and lakes when summer temperatures go up and there’s less rainfall, and when you are around a waterway, just be aware of the water quality as some blooms can be hazardous to your health or your animals.”
Cyanobacteria are single celled organisms
which naturally occur in water environments, but in warm
nutrient rich conditions cyanobacteria cells can multiply
quickly to form algal blooms. Large numbers of cyanobacteria
can also grow as mats on river and lake beds which can then
detach and float to the surface.
In previous summers,
cyanobacteria mats have been found in Hawke’s Bay’s
shallow braided rivers. The mats are identifiable by a
strong musty smell and can vary in colour from brown/black
when in the water to a pale brown/whitish colour when
dry.
Some cyanobacteria species produce toxins (cyanotoxins), which pose a risk to humans and animals when consumed or by direct contact during recreational activities. River users should avoid any contact with algal mats, avoid swimming in water where the mats are present, and keep dogs from scavenging around the river.
Hawke’s Bay District Health Board Medical Officer of Health, Dr Lester Calder, says “Contact with the toxic form of the mat may cause vomiting, diarrhoea, skin rashes and numbness or tingling around the mouth.”
He also warns pet owners that dogs are particularly susceptible to the toxins with paralysis a possible outcome.
Anyone displaying signs of
illness after being in a river bed should seek medical
advice from a doctor immediately. Similarly, dogs or other
animals that get sick after being in a river should get
prompt veterinary attention.
The HBDHB Public Health Unit
should be alerted in the event of health issues occurring
after contact with river or lake water. The On Call Health
Protection Officer can be contacted on 06 834
1815.