[Acute toxicity of 5 pollutants on 4 fresh-water invertebrate species]

The animals stay in solutions for 4 days at different concentrations of each agent: regression lines (log concentration-probit) allow us to calculate the lethal concentration values for 50% of the animals tested (LC 50). Animals are affected by concentrations ranging from 0,003 to 9,0 X 10(-6) of insecticides, 2 to 16 X 10(-6) of herbicide, 9 to 50 X 10(-6) of detergents. As a general rule, the four studied species can be classified by decreasing sensibility in the following order: Gammarus, Cloeon, Chaoborus and Lymnea.