Accumulation of Copper and Cobalt by Blue-Green Algae at Different Termperatures

Abstract

Two species of blue-green algae Anacystis nidulans and Spirulina platensis, grown in artificial aqueous culture medium, were treated with Cu and Co at different temperatures in order to study accumulation of these elements by the organisms. Metal concentrations used were 0.5, 1.0, 2.0 and 4.0ppm at different temperatures viz, 25, 30, 35, 40 and 45°C. Both these species showed high capacity to accumulate the metals. Concentration factors (CF) were in the range of 10³-10⁴. Metal accumulation followed the relation m= KC ⁿ where m=molar concentration of metal in the algae, C=molar concentration of initial total metal in the medium, K and n=constants. Metal accumulation by algae was higher at high temperature than at lower ternpera-tures. A negative correlation between metal accumulated and the survival ratio of the algae when treated with different metals was observed, indicating the importance of passive absorption mechanism.

Key Words:

• Concentration factor
• cyanobacteria
• survival ratio
• temperature
• copper
• cobalt