Abstract
This investigation was conducted to determine the total metal absorbed (μgg-1 dry wt), removal (% day-1), and accumulation rates of M. aeruginosa (Cyanophyceae), S. quadricauda (Chlorophyceae), and A. granulata (Bacillariophyceae) exposed to the different concentrations of copper, zinc, cadmium, and their combinations. Upon exposure to the different single and combination concentrations of heavy metals, the highest total metal absorbed, removal, and accumulation rates of thethree organisms were obtained for copper while their lowest values were obtainedfor cadmium. Total metal absorbed, removal, and accumulation rates were species specific. M. aeruginosa showed the highest values for all metals tested while S. quadricauda showed the lowest values. The accumulation rates of M. aeruginosa for a specific heavy metal were hardly affected by the presence of other metals inthe solution. However, in S. quadricauda and A. granulata, there were some remarkable reductions observed in their accumulation rates. This study provides information on the efficiency of the three freshwater microalgae to sequester heavy metals from an aqueous system as a possible pollution control and biomonitors or detectors of the biological impact of industries.
