The Joint Toxicity Of Deicing Salt And Heavy Metals On The Growth And Physiological Property Of Algae

With the development of society. more and more deicing salt was applied to clear snoxv in winter. Lots of deicing salt got into water. it was harmful to the growrth of aquatic creatures and caused the water pollution in different level. Heavy metal ions in water caused the aquatic organisms damage. Deicing, salt and heavy metal coexisted in the water would cause combined pollution. effected the growth of aquatic organisms and the ecological balance in water.This paper studies the effects of deicing salt and heavy metal ions on the growth behavior and the change of contents of chlorophyll (a). proteins and polysaccharides of algal Chlorella vulgaris when they were single and in different ratio. It applied toxic unit. additional index and mixture toxic index to evaluate the joint toxic effects of deicing salt and heavy metal ions. The results show that inoryanic deicing, salt obviously inhibited the algea growth when concentrations reach20/L and organic deicing salt obviously inhibited the algea growth when concentrations was higher than4g/L. The96h-EC50of inorganic and organic deicing, salt to Chlorella vulgaris were4.973g/L and7.109g/L. the toxicity of inorganic deicing salt on Chlorella vulgaris was higher than organic deicing salt. Algal cell density increased when the Cu2+concentrations was lowerthan O.O5mg/L and it obvioiusly inhibited the algea orowth when the Cu2+concentrations was higher than O.5mg/L. Algal cell density increased when the Zn2+concentrations was lower than0.5mg/L and it obviously inhibited the algea growth when the Zn2+concentrations reach5mg/L. The96h-EC50of Cu2+and Zn2+to Chlorella vulgaris were0.356mg/l.and24.244mg/L. the toxicity of Cu2+on Chlorella vulgaris was higher than Zn2+.Deicing salt and Zn2+in low concentrations promoted synthesis of chlorophyll (a) in algae cells. Deicing salt in hiih concentrations inhibited the synthesis of chlorophyll (a). protein and polysaccharide in algae cells. Cu2+in0.05mg/L concentration and Zn2+in0.5mg/L, concentration were suitable for protein and polysaccharide synthesis. The results of evaluation were mostly synergistic effect when deicing salt and heavy metal ions in different proportion. Stress of Cu2+and deicing salt mixed exposure to the growth of Chlorella vutgaris was lower than single. Stress of Zn2+and deicing salt mixed exposure to the growth of Chlorella vulgaris was higher than single. Inhibition of Cu2+and deicing salt nixed exposure to the synthesis of chlorophyll (a) of Chlorella vulgaris was lower than single and Zn2+was Higher than single. Inhibition of deicing salt and heavy metal ions mixed exposure to the synthesis of proteins and polysaccharides of Chlorella vulgaris was mostly higher than single.