Toxicity and Bioaccumulation of Lead and Cadmium in Marine Protozoan Communities

The behavior of lead and cadmium in a protozoan community was studied in order to obtain new data regarding the toxicity and bioaccumulation of these heavy metals. For this purpose, microcosms with different concentrations of the pollutants (without metals, 500 μg Cd and Pb·L−1 1000 μg Cd and Pb·L−1) were used. Protozoans bioaccumulated 7.03–207.00 μg Pb·g−1 dry weight (dw) and 0.05–332.75 μg Cd·g−1 dw, representing an accumulation capacity of up to 161.45 μg Pb·g−1 dw and 310.75 μg Cd·g−1 dw more than that of the bacteria. The addition of both metals caused a significant reduction in the density of protozoans. These data were compared with those obtained previously in treatments that used these metals separately.