[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitrogen （DIN） in east water-source and inflow rivers of Chaohu Lake were investigated, and their effects on water qual- ity were examined. [Result] The concentrations of NH3-N and NO2--N were the high in flood season, and low in non-flood season, while the concentration of NO3--N pre- sented the opposite trend; the concentration of NO3--N was the highest in Shuangqiao estuary, where the pollution was the worst. DIN in Zhegao estuary and Xiaozhegao estuary was mainly caused by domestic sewage and industrial wastewaters; surface runoff and pollution from ships contribute the most to the DIN content in Shuangqiao estuary. [Conclusion] This study provided basic data and theoretical basis for the control and management of eutrophication in Chaohu Lake.
[Objective] The research aimed to study the toxicity effect of microsystin on Hydra（aquatic animal model）.[Method] Hydra magnipapillata was as the experimental material.Under the different concentrations of MC-LR solution,its acute toxicity effect on Hydra magnipapillata was observed.[Result] The half lethal concentration（LC50） of MC-LR on Hydra magnipapillata at 24 h was 12.158,4.029 mg/L at 48 h and 1.799 mg/L at 72 h.[Conclusion] Hydra magnipapillata would die when treated by the low concentration of MC-LR solution.It illustrated that MC-LR produced by algal blooms caused the damage on some aquatic animals,and even some low-level aquatic animals died,such as Hydra magnipapillata and so on.The research provided some reference basis for the detection and assessment of water body pollution.
