Effect of linear alkylbenzene sulfonate on population growth of Daphnia galeata: a life table evaluation.

The chronic effect of linear alkylbenzene sulfonate (LAS12) on a daphnid species (Daphnia galeata) was examined by the life table experiment. The estimated responses in the intrinsic rate of population growth r were analyzed with two alternate concentration-response functions, i.e., the power function and the quadratic function. Based on the best-fit power function model with biases corrected by the jackknife procedure, the population-level EC50, which is defined as the concentration of chemicals that reduces the population growth rate (the intrinsic rate of natural increase) by 50%, was estimated as 2.5 mg/L. The 48-h acute immobility test yielded EC50 of 4.6 mg/L. The population-level effect of LAS12 on this test species is considerably more sensitive than the acute lethal effects to neonates.