Cadmium IC50 determinations on Chlorella vulgaris [Algae, pollution] involving different parameters

The ecotoxicity of cadmium nitrate to the alga, Chlorella vulgaris, was assessed by growth parameters of opacimetry (665 nm), cell count biomass volume estimation using the Coulter counter, and ATP and chlorophyll levels. Determination of IC50 by cell counting afforded lower values than by the other methods, while opacimetry gave the highest values, and this method was considered to be the most satisfactory for routine screening procedures.