What do the Low, Moderate and High symbols for the blue-green algae mean?
• The World Health Organisation (WHO) have established three hazard levels against which storage operators and water users can assess the danger posed by blue-green algae during primary contact water recreation activities (i.e. swimming, canoeing, water skiing etc). The following values are based on the WHO guidelines for safe practice in managing bathing waters which may produce or contain cyanobacterial cells and/or toxins (Chorus & Bartram 1999): Blue-green algae can cause irritation to any part of the body that is directly exposed to it. This irritation is usually in the form of a skin rash, eye irritation, or earache. The more blue-green algae that is present in the water, the greater the chance that some irritation will occur if you swim in the water. The levels on the sign are an indication of this risk given the current levels of blue-green algae. If the blue-green algae indicator indicates a HIGH level, there is a high chance that the average person will suffer some form of ir
