Cadmium and Chromium Toxicity to Pseudokirchneriella subcapitata and Microcystis aeruginosa

摘要

The toxicity of cadmium and chromium to Pseudokirchneriella subcapitata and Microcystis aeruginosa was evaluated through algal growth rate during 96h exposure bioassays. Free metal ion concentrations were obtained using MINEQL~+ 4.61 and used for IC50determination. Metal accumulations by the microorganisms were determined and they were found to be dependent on the concentration of Cd~(2+) and Cr~(6+). IC50 for P. subcapitata were 0.60 mu mol L~(-1) free Cd~(2+) and 20 mu mol L~(-1) free Cr~(6+), while the IC50 values for M. aeruginosa were 0.01 mu mol L~(-1) Cd~(2+) and 11.07 mu mol L~(-1) Cr~(6+). P. subcapitata accumulated higher metal concentrations (0.001 - 0.05 mu mol Cd mg~(-1) dry wt. and 0.001 - 0.04 jumol Cr mg~(-1) dry wt) than the cyanobacteria (0.001 - 0.01 mu mol Cd mg~(-1) dry wt and 0.001 - 0.02 mu mol Cr mg~(-1) dry wt). Cadmium was more toxic than chromium to both the microorganisms.