Bioaccumulation of Cadmium in Marine Diatom: Thalassiosira allenii Takano

The present study achieved cadmium bioaccumulation ability using growth kinetics and ICP-OES for Cd measurements in marine diatom Thalassiosira allenii Takano. T. allenii cells were exposed to different cadmium concentrations (0.5, 1, 2, 5, 10, 25, 50, 75, and 100 mg. Cd L-1) for 4 days. T. allenii cells were seen to have bioaccumulation ability both in cells and cellular surfaces. The cadmium uptake of T. allenii species followed a linear trend for most of days for <= 25 mg L-1Cd concentrations while the cell growth was inhibited at concentrations of >25 mg L-1Cd. T. allenii removed much of cadmium by taking it into the cells in <= 10 mg. L-1 Cd concentrations in the medium. While the adsorption on the cell surfaces is dominant in cells on the first day, the amount of Cd allowed in the cell has become dominant beginning with the second day. The growth rate decreased with increasing Cd concentration and remained stable at about 0.1-0.2 day(-1). However up to the 5 mg. L-1 Cd concentration, the growth rates are not different from the control and continued for about 0.3-0.4 day(-1). When T. allenii species is used in the bioremediation systems, this limit value does not affect growth of the species.