Abstract: Bioassay tests of Scenedesmus obilquus,Daphnia magna and Brachyddanio rerio were conducted to evaluate environmental quality of the sediment in the Baoying Lake,Jiangsu Province. Results showed that extractive solution from the sediment had no obvious acute toxic effect on Brachyddanio rerio and Daphnia magna.However,the solution significantly stimulated growth of Scenedesmus obilquus compared with water from the lake,and the higher the concentration of the solution,the more significant of the stimulation.Results of chemical analysis showed that phosphorus concentration was higher in the solution than in the water,indicating release of phosphorus from the sediment to the water which stimulated the eutrophication of the lake.

Key words: sediment, bioassay, eutrophication, Baoying Lake, Jiangsu Province