The relationship between chronic values in toxicity tests with ceriodaphnia dubia

摘要

Chronic toxicity tests using Ceriodaphnia dubia are conducted across the United States by facilities releasing wastewaters into bodies of freshwater, as well as by the appropriate agencies governing environmental protection. Until recently, the chronic values used for decision making were the "No Observable Effect Concentration" (NOEC), the "Lowest Observable Effect Concentration" (LOEC) and the "Chronic Value" (ChV). Currently, "Inhibition Concentrations of a Given Percent" (IC_p) are being considered, for effluent permitting, by a number of states. The IC_p value is the concentration at which the reproduction of C. dubia is inhibited by "p" percent. It has been asserted that the IC_(25) is aproximately equivalent to the NOEC and that the IC_(50) is similar to the ChV.