Benthic Cyanobacteria: An Aesthetic and Toxic Risk to Be Evaluated

While management of the risks from pelagic cyanobacteria are well established, there are no protocols for management of risk caused by benthic cyanobacteria. Recent research shows that benthic cyanobacteria are potentially major sources of taste and odour compounds, and toxins in Australian drinking water reservoirs. The risk represented by the production of toxins by benthic cyanobacteria is poorly understood in drinking water supplies. The risk of exposure to benthic algal toxins is accentuated in recreational and recycled water.

While conventional treatment plants remove most of the toxins, multiple barriers are still required and powered activated carbon needs to be used. Without a reliable monitoring regime for benthic cyanobacteria, this safety precaution cannot be initiated. The case of CYN is particularly pertinent because 50% of the toxin is found outside of the cells, even in healthy populations, and it is therefore not removed during coagulation.

This project evaluated the actual risk that toxigenic benthic algae represent in water sources by establishing knowledge on the rate of toxin production, dispersion and fate through the water source and treatment facilities. Complementary to this, taste and odour compounds and candidate genes were monitored. Research Partner: Water Research Australia. Published in 2020.