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Brazilian Archives of Biology and Technology

Print version ISSN 1516-8913

Abstract

RODGHER, Suzelei; ESPINDOLA, Evaldo Luiz Gaeta; SIMOES, Fernanda Cristina Fonseca  and  TONIETTO, Alessandra Emanuele. Cadmium and Chromium Toxicity to Pseudokirchneriella subcapitata and Microcystis aeruginosa. Braz. arch. biol. technol. [online]. 2012, vol.55, n.1, pp. 161-169. ISSN 1516-8913.  http://dx.doi.org/10.1590/S1516-89132012000100020.

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 IC50 determination. Metal accumulations by the microorganisms were determined and they were found to be dependent on the concentration of Cd2+ and Cr6+. IC50 for P. subcapitata were 0.60 µmol L-1 free Cd2+ and 20 µmol L-1 free Cr6+, while the IC50 values for M. aeruginosa were 0.01 µmol L-1 Cd2+ and 11.07 µmol L-1 Cr6+ . P. subcapitata accumulated higher metal concentrations (0.001 -0.05 µmol Cd mg-1 dry wt. and 0.001 -0.04 µmol Cr mg-1 dry wt) than the cyanobacteria (0.001 -0.01 µmol Cd mg-1 dry wt and 0.001 -0.02 µmol Cr mg-1 dry wt). Cadmium was more toxic than chromium to both the microorganisms.

Keywords : Toxic effects; algae sensitivity; metal accumulation; IC50.

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