Bioaccumulation of Cadmium in an Experimental Aquatic Ecosystem Involving Phytoplankton, Zooplankton, Catfish and Sediment

Abstract

The accumulation of cadmium (Cd) was studied in an experimental aquatic ecosystem involving the phytoplankton, Chlorella regularis, the zooplankton, Moina macrocopa, and the catfish, (cross bridge Clarias macrocepharus X Clarias gariepinus), and sediment. All organisms were selected in this study because of their economically importance. The accumulation of cadmium was mainly on phytoplankton. The cadmium concentration in all organisms increased with increasing cadmium concentration in the ecosystem. When the input cadmium concentration was 3.5 mg l^-1, cadmium accumulated in the surface of sediment (0-1 cm.), phytoplankton, zooplankton, and catfish were 5.53±0.26, 586.18±23.37, 141.52±26.74 and 10.29±0.47 μg g^-1 (dry wt.), respectively. Results showed that phytoplankton, zooplankton, and catfish exposed to cadmium represents a risk of secondary poisoning for their predators and such a risk could affect humans. The accumulation of cadmium in sediment may have an effect on benthic organisms.