Environment Southland’s latest monitoring has found elevated levels of toxic algae in the Waiau River near the Excelsior Creek inflow.
Toxic algae (benthic cyanobacteria) can be recognised in rivers and streams as a dark green/brown slime on rocks, or dark brown/black mats at the water’s edge. Several factors can contribute to the growth of toxic algae, such as high levels of nutrients, run-off into waterways, a sudden increase in temperature, and low flows.
Environment Southland senior scientist Katie Blakemore said Waiau River users and animals should avoid contact with algal mats and remain alert in other parts of the river for algal growth or mats of algae floating in the water.
These algae can produce toxins that are harmful to people and animals if swallowed, or through contact with skin. People and animals (dogs in particular) should avoid contact with the river and be mindful of the potential health risks until health warnings are removed.
If you experience health symptoms after contact with contaminated water, visit a doctor immediately. If you are concerned that any animals have consumed toxic algae or contaminated water, they should be taken to a vet immediately.
Environment Southland monitors toxic algae monthly at a number of river and lake sites across Southland.
For further information visit Environment Southland’s website www.es.govt.nz/toxic-algae