African Wildlife & Environment Issue 84 2023

CONSERVATION

Reason #4:

us that we need to do something different. Let us manage the problem by reducing the chance of HAB contaminated aerosol production, until such time as we know more about the exact fate and pathway of the toxins associated with cyanobacterial blooms. Let us embrace nature and adapt, rather than trying to overwhelm nature to conform to our will as a species. REFERENCES Hu, L., Liu, J., Zhu, Y., Diaz-Perez, Z., Sheridan, M., Royer, H., Liebensperger, R., Maizel, D., Brand, L., Popendorf, K., Gaston, C. & Zhai, R. 2020. Exposure to Aerosolised Algal Toxins in South Florida Increases Short- and Long-Term Health Risk in Drosophila Model of Aging. In Toxin , 12(12):787. doi: 10.3390/toxins12120787 Lee, S., Choi, B., Kim, S.J., Kim, J., Kang, D. & Lee, J. 2022. Relationship Between Freshwater Harmful Algal Blooms and Neurodegenerative Disease Incidence Rates in South Korea. Environmental Health , 21:116. Matthews, M.W. 2014. Eutrophication and cyanobacteria blooms in South African inland waters: 10 years of MERIS observations. Remote Sensing of the Environment. 155:161–177. http:// dx.doi.org/10.1016/j.rse.2014.08.010 Matthews, M.W., & Bernard, S. 2015. Eutrophication and Cyanobacteria in South Africa’s Standing Water Bodies: A View from Space. South African Journal of Science . Vol. 111. No. 5/6.

Water skiing, and powerboat use, both result in what is called a ‘rooster tail’ behind the boat.This plume of water is a generator of aerosols, to which the towed skier would be directly exposed, but the drifting particles of microscopic size would create a defined zone of contamination, dependent on the prevailing wind, potentially up to a 5km radius from the HAB source. Having presented this logic to the reader, but with the limitation of space needed to expand on the issue to the extent needed, the purpose of this article is to open a debate informed by science, involving decision-makers, regulators and persons directly affected by the human health implications of aerosolized HAB water. In the professional opinion of the author, more consideration ought to be given to the establishment of floating wetlands, anchored in three-dimensional space to allow for recreational use of the water, but also covering much of the water. The benefits of this are significant. For starters, this would tilt the mass balance away from the dominance of suspended procaryotes like cyanobacteria. Hyacinth might be unsightly, but its presence will not harm the health of those living next to the dam. It might therefore be prudent to learn to live with hyacinth, rather than constantly trying to unsuccessfully eradicate them. The greater the coverage by floating wetlands, the less is the possibility of producing aerosols containing HAB toxins. This is a benefit until the nutrient inflow into the system can be reduced. When the fundamental principle of the mass balance is applied, it tells us that the only effective way to manage eutrophication, is to reduce (or eliminate) the nutrient loads in the water column. Floating wetlands do just that, by engineering solutions in partnership with nature, rather than constantly fighting with nature. In conclusion, the most prudent approach when confronted by high risk with incomplete information, is to apply the precautionary principle. In the case of our large dams, we know that more than two thirds are eutrophic, and this number is growing. We also know that we have never managed to return a eutrophic system back to its previous status, so our current science, engineering and technology tells

Prof Anthony Turton Centre for Environmental Management

University of the Free State tony@anthonyturton.com

16 | African Wildlife & Environment | Issue 84 (2023)