With South Africa finding itself in the grip of a searing heat wave, and water sources running dry, the reality of water pollution and harmful blue-green algae is becoming a more worrying reality.
WHAT IS BLUE-GREEN ALGAE?
Blue-green algae (or cyanobacteria) is a toxic bacteria that grows in warmer, nutrient-rich water. The bacteria ends up depleting the water of oxygen and releasing several toxins that could pose serious health risks to humans and animals.
According to a study by the South African Journal of Science in May this year, South Africa has the highest known levels of blue-green algae contamination in the world. About two thirds of our national resource is contaminated, and that figure will grow.
THE EXTENT OF THE DAMAGE
Between 2002 and 2012, 62% of 50 analysed water bodies contained high levels of blue-green algae. Of the 50 bodies of water, 26 were found to pose a high health risk due to surface scum (a toxic layer or film on the water surface). However, a handful of water bodies are worse off than the rest, with almost 30% of the water surface covered in scum.
- Barberspan Dam >45%
- Hartbeespoort Dam >45%
- Koppies Dam >45%
- Spitskop Dam ±30%
- Vaal Dam ±30%
- Lake Chrissiesmeer ±30%
Such high levels of contamination are an immediate concern with regard to drinking water, agricultural and recreational water use.
A number of reservoirs are also showing high levels of algae contamination.
- Mthatha Dam
- Ncora Dam
- Erfenis Dam
- Krugerdrift Dam
- Ntshingwayo Dam
- Allemanskraal Dam
It has been estimated that 18 of 25 major river catchments are also contaminated.
Currently, there isn’t an effective treatment method available. Water treatment plants use a filtering process to remove most of the blue-green algae from supplied water before they reach our taps. However, there isn’t a large-scale treatment method to treat entire bodies of water at once.
Fortunately, there are other ways to prevent and/or limit blue-green algae:
- Improve the management of wastewater disposal systems.
- Regulate pollution caused by fertilisers from the agricultural sector more efficiently.
- Educate yourself and know how to identify contaminated water.
Be sure to read part 2 on blue-green algae and find out how you can protect yourself and the health symptoms to look out for.