Prediction of mortality in chronic toxicity tests on Daphnia magna

The present study deals with the analysis of mortality of Daphnia magna in chronic toxicity tests. Linear regression models were used to assess the possibility of predicting the probabilities of death over the long term on the basis of those recorded early in the toxicity test. The results based on data from toxicity tests with cadmium and pyridine, which yielded different mortality patterns over time, indicate that such predictions are practicable. These results suggest the feasibility of performing empirical relationships which would enable toxicologists to predict mortality over 21 days (usual length of the Daphnia magna chronic toxicity tests) and/or longer using the information obtained from shorter exposure to toxicants.