International Journal of Environmental Science and Development

Abstract—Not much has been done to investigate the uptake and synergic effect of multiple classes of cyanotoxins on aquatic plants. Two aquatic plants Ludwigia adscendens and Amaranthus hybridus (biomass ranging 3.27 to 9.4 gL-1) were exposed to contaminated water for 14 days to test the synergic effects of cyanotoxins in solution on the plants. The plants were exposed to concentrations of 5.385-7.641 μg mL-1 for MC-LR; 8.905 μg mL-1 for MC-RR). L.adscendens accumulated microcystins up to a concentration of 0.04595 ± 0.0004 ng mg-1 wet weight and A.hybridus accumulated microcystins up to a concentration of 0.0166 ± 0.0016 ng mg-1 wet weight of plant material over the 14 days. Except in beaker experiments where the plants were exposed to artificial water dosed with crude extracts, the treatments and their respective controls did not show any significant difference in toxin removals (one-way ANOVA at p=0.05), showing that the plants were unable to significantly remove the toxins from solution. When exposed to raw dam water, both plants were negatively affected as demonstrated by the loss in fresh wet weight. It was thus concluded that the cyanotoxins had adverse effects on aquatic plants at the concentrations used.

Index Terms—Cyanotoxins, aquatic plants, Ludwigia adscendens, Amaranthus hybridus, microcystins.

The authors are with the Environmental Remediation and Water Pollution Chemistry Research Group, Department of Ecology and Resources Management, University of Venda, Private bag X5050, Thohoyandou, 0950, Limpopo, South Africa (e-mail: gpindihama@gmail.com, Mugera.Gitari@univen.ac.za).

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Cite: Glynn K. Pindihama and Mugera W. Gitari, "Uptake and Growth Effects of Cyanotoxins on Aquatic Plants Ludwigia Adscendens and Amaranthus Hybridus in Raw Surface Waters," International Journal of Environmental Science and Development vol. 8, no. 2, pp. 93-101, 2017.