Phytoremediation of Cd2+ by Marine Phytoplanktons, Tetracelmis chuii and Chaetoceros calcitrans

Abstract

The use of marine phytoplankton, Tetracelmis chuii and Chaetoceros calcitrans as phytoremediator has already been reported. However their use as phytoremediator on the cadmium polluted marine has not yet well understood. Therefore, this study was conducted to evaluate the influence of the Cd2+ concentration, interacting time, and medium pH on accumulation of Cd2+ in the phytoplankton. Methods of analysis and data collection were carried out on 1) the growth rate, the number of phytoplankton cells, and the content of chlorophyl-A; 2) the Cd2+ concentration in phytoplankton at various interacting times and medium pHs; and 3) infrared spectra of phytoplankton biomasses before and after interaction with Cd2+. The growth of phytoplankton and the content of chlorophyl-A after the addition of Cd2+ into the T. Chuii medium decreased, while that after the addition of Cd2+ into the C. Calcitrans medium increased. The optimum accumulation occurred after 15 min at the pH of 8, i.e. 13.46 mg Cd2+ per g T. Chuii and 1055.27 mg per g C. Calcitrans. The functional groups of T. chuii involved in the bioaccumulation of Cd2+ are OH, -CN, S=O, N-O, S-S and M-S, while that of C. Calcitrans are OH, C=O, S-S, M-S and C=C.