The application of bioaccumulation in environmental treatment has become a significant research area in the past ten years. Bioaccumulation for mixture of heavy metals is of high importance for their application for industrial purpose. Aspergillus tamarii growth decreased with increasing heavy metals mixture of Cd+2, Ni+2, Co+2 and pb+2 concentrations, in the presence of oxalic and citric acids. There is no relationship between the growth of A. tamarii and bioaccumulation of heavy metals. The absorbed percentage of heavy metals decreased with increasing heavy metals mixture concentrations. On the other hand the addition of oxalic and citric acids increased the absorbed amount of heavy metals. The absorbed amount of Co+2 was higher than other metals in the presence of oxalic acid at all concentrations of heavy metals mixture, but in the presence of citric acid, lead was the major absorbed metal compared with other metals at 50 ppm of heavy metals mixture.
Key words: heavy metals, oxalic acid, citric acid, Aspergillus tamarii, bioremediation.
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