| Abstract: | The freshwater green alga Ankistrodesmus falcatus was cultured in increasing concentrations of Cr, Hg, Cd, Zn, and Al to evaluate the effect of these cations on its growth. Algal growth was estimated by absorbance at 750 nm. Potassium dichromate was used as reference for test reproducibility. The EC50 for 3 tests was 1.890 mg L−1 with a coefficient of variation of 40.25%. The 96 h static EC50's for heavy metals (in mg L−1 of nominal concentrations) were as follows: Cr6+/K2Cr2O7, 1.050; Hg2+/Hg(SCN)2, 0.162; Hg2+/HgCl2, 0.074; Cd2+/CdCl2 · H2O, 0.292; Zn2+/ZnSO4 · ZH2O, 2.432; and Al3+/Al2(SO4)0 · 18H2O, 0.904. Thus yielding a toxicity series such that Hg > Cd > Al > Cr > Zn. These preliminary results suggest that bioassays using A. falcatus could be suitable for evaluating the toxicity of heavy metals in freshwaters. © 1997 by John Wiley & Sons, Inc. Environ Toxicol Water Qual 12: 11–14, 1997 |
