Effect of Different Concentrations of Diuron Herbicide on Chlorophyll a and Growth Rate of Blue-green Algae; Anabaena flos-aquae

Aims: The aim of this study was to investigate the effect of Diuron in vitro on the growth rate of Anabaena flos-aquae in order to determine the toxicity of diuron by calculating EC10, EC50, EC90, and MAC value for this alga to control flourishing in this phytoplankton.
In this experimental research, the growth rate of Anabaena flos-aquae was investigated under the influence of diuron. This experiment was conducted in 96 days with 6 treatments (0.0005, 0.009, 0.016, 0.03, 0.054, and 0.01 mg/l), 1 control group, and 3 repetitions of the treatments in 500cc Erlenmeyer flasks. The growth rate was measured, using cell counting, turbidimetric measurement, and chlorophyll a measurement methods. Then, achieved quantities of EC were used in four 500cc Erlenmeyer flasks and the concentration of algae was evaluated through cell counting in 24-hours periods during 96 hours. Using SPSS 17 software, one-way ANOVA was used to compare the increase percentages between different treatments.
Findings: Quantities of EC10, EC50, EC90, and Mac value of this toxicant for the algae according to chlorophyll a concentration were reported 0.006, 0.01, 0.05, and 0.001 mg/l, respectively. The frequency of Anabaena flos-aquae was significantly different in presence of concentrations obtained from EC indices and decreased sharply in EC90 quantities.
The use of diuron in the proposed concentrations reduces its risk from the perspective of toxicity and contamination of other components of the ecosystem and it is more effective in this group of algae.