Kinetic parameters of survival in daphnia under toxic environmental pollution

The combined effects of oil, copper, and chromium on the survival of the cladoceran crustacean Daphnia magna Straus was studied. The theoretically expected rates of mortality in crustaceans at various concentrations of toxicants at their combined action were calculated using the inhibition model commonly used in biochemistry for describing enzymatic kinetics. It was shown that the experimental and theoretically expected mortality rates of crustaceans conform well (the relative value of standard deviation is 17.58%). The results of the experiments show that the principles of enzymatic kinetics are applicable for studies on toxic effects on zooplankton. This makes it possible to use these principles for a quantitative assessment of the relations between the concentrations of chemical pollutants and the extents at which these chemicals suppress aquatic fauna.