Longevity and reproduction of Daphnia pulex (de Geer) exposed to cadmium-contaminated food or water

The effect of cadmium on the survival and reproductive capacity of Daphnia pulex was determined. Cadmium was present either in the water at chronic (1–30 μg Cd/litre) and acute (40–90 μg Cd/litre) levels or in the algal food source, Chlorella pyrenoidosa. The average longevity of D. pulex was not affected by exposure to 1 μg Cd/litre but it was reduced in a dose-dependent manner between 5 and 30 μg Cd/litre. Exposure to cadmium had no effect on the number of days to onset or frequency of reproduction but it did cause a reduction in the percentage of adults producing young, the number of broods per adult, the number of young per brood, the number of progeny per adult, the intrinsic rate of natural increase (r), and the mean generation time (T). Cadmium-laden Chlorella caused the same effects as did exposure to 1 μg Cd/litre.