This rise in nutrient levels can in turn contribute to the growth of algal blooms. This is Cylindrospermum, one of about 12 forms which are toxic to both people and stock. During blue-green algae outbreaks, communities along the river have to be very careful about the water they use. In towns, expensive filtering is needed to make the water safe for drinking. Signs alert people that water is affected by blue-green algae.
Water is tested regularly for the presence of blue-green algae.
People living on stations along the Darling River take water samples every fortnight with sterilised bottles. The media is playing an important part in informing the public about blue-green algae. Some radio stations broadcast alerts when levels are high. In recent years, the conditions which cause blue-green algae to grow and multiply rapidly have become more frequent. High levels of nutrients in rivers can contribute to the growth of blue-green algae.