Abstract: The cladoceran Moina macrocopa was used as test animal to investigate the effects of ibuprofen concentrations (0, 0.45, 0.9, 1.8, 3.6, 7.2 and 14.4 mg·L^-1) on its life table demographic parameters under low (0.5×10⁶ cells·mL^-1), medium (1.0×10⁶ cells·mL^-1), and high (2.0×10⁶ cells·mL^-1) densities of Scenedesmus obliquus. The results showed that at low and high food levels, ibuprofen concentration significantly affected the intrinsic rate of population increase and the life expectancy of M. macrocopa, respectively. At all the three food levels, however, ibuprofen concentration did not significantly affect the generation time, net and gross reproduction rate of M. macrocopa. Compared with the controls, the intrinsic rate of population increase of M. macrocopaexposed to ibuprofen at 0.45, 0.9, 3.6 and 14.4 mg·L^-1 was significantly decreased at low food level. At high food level, the life expectancy at hatching of M. macrocopa exposed to ibuprofen at 3.6 and 14.4 mg·L^-1 was significantly increased. The results indicated that at low food level, certain concentrations of ibuprofen had negative effect on the population growth of M. macrocopa, which disappeared at medium and high food levels. At high food level, ibuprofen had positive effect on the survival of M. macrocopa, which disappeared at low and medium food levels. The effects of ibuprofen concentration on demographic parameters of M. macrocopa were dependent on food levels.

Key words: ibuprofen concentration, reproduction, Moina macrocopa, survival, population growth, algal density.