藻类水体Cd2+毒性快速监测新方法研究

采用藻类生长抑制试验和光合活性抑制试验两种方法对蛋白核小球藻受不同浓度Cd2+胁迫作用下叶绿素浓度及藻活性荧光参数进行测量,依据Sigmoidal曲线拟合及单因素方差分析(one-way ANOVA)的方法对Cd2+不同胁迫时间下藻活性抑制率和96 h比生长率抑制率的相关性进行研究.结果表明,48、53、72、77和96 h的藻活性抑制率和96 h比生长率抑制率间具有较好的S函数关系(R2>0.95),因此可采用藻活性抑制率48 h-EC10和53 h-EC10来代替96 h的藻类半数比生长率抑制率EC50进行Cd2+藻类毒性实验评价.进一步分析了蛋白核小球藻受Cd2+胁迫48 h和53 h藻活性抑制率和Cd2+毒性当量的剂量-效应关系.该方法为实验室内单一Cd2+毒性的监测提供了一种快速有效的新方法,为水环境综合毒性预警提供了一种切实可行的方法依据.

Study on a New Method of Fast Monitoring Toxicity of Cd2+ by Algal in Water

Chlorophyll concentration and photosynthesis activity fluorescence parameters of Chlorella pyrenoidosa stressed by different concentrations of Cd²⁺ were measured based on algal growth inhibition tests and photosynthetic activity inhibition tests. The relationship between the algal photosynthetic activity inhibition rate and 96 h inhibition rate of specific growth rate at different Cd²⁺ stress times was studied by sigmoidal curve fitting and one-way ANOVA analysis. The result shows that S function relevance exists between the algal photosynthetic activity inhibition rates for 48 h,53 h,72 h,77 h and 96 h respectively and 96 h inhibition rate of specific growth rate(R²>0.95).Consequently, EC₁₀ (10% effective concentration) after 48 h and 53 h inhibition in photosynthetic activity inhibition tests could be used to represented EC₅₀ (50% effective concentration) in 96 h algal growth inhibition tests for evaluating the Cd²⁺ toxicity. Dose-response relationships between the algal photosynthetic activity inhibition rates after 48 h and 53 h inhibition and Cd²⁺ toxic equivalency quantity were further analyzed. The method provided a rapid and viable new thought to monitoring single Cd²⁺ toxicity in lab and early warn integrated toxicity of pollution in water.