[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.