不同pH条件下Cr6+对3种藻的毒性效应(The Toxicological Effects of Cr6+ on Chlorella Vulgaris, Scenedesmus Obliquus and Microcystis Aeruginosa at Different pH Values)

目前我国水质量生态基准的研究较为零星、分散.研究了不同pH条件下Cr6+对3种藻的毒性效应,以期为我国水生态基准的科学制定以及基准的相关研究工作提供参考.选取小球藻、斜生栅藻和铜绿微囊藻3种典型的藻种,在pH为7.0,8.0和9.0三个条件下,依据OECD-201藻类生长抑制实验指南,以72h藻生物量为测试终点,计算3种藻的比生长率,以及Cr6+对3种藻产生毒性效应的NOEC、LOEC、EC10和EC20值.结果表明,在本实验条件下,在不同pH条件下藻种生长不同,小球藻的最适pH值为7.0,斜生栅藻和铜绿微囊藻的最适pH值为9.0;在不同pH条件下,Cr6+对小球藻、斜生栅藻和铜绿微囊藻的毒性作用不同,Cr6+对小球藻在pH=7.0时毒性最小,对斜生栅藻和铜绿微囊藻在pH=9.0时的毒性最小.在藻最适生长的pH条件下,Cr6+的毒性可以达到最小程度;铜绿微囊藻对Cr6+比斜生栅藻和小球藻更加敏感.

The Toxicological Effects of Cr6+ on Chlorella Vulgaris, Scenedesmus Obliquus and Microcystis Aeruginosa at Different pH Values

At present,the study of the water quality ecological criteria in China is scattered.The purpose of this study is to provide the reference to the establishing of the ecological criteria and the related study.According to the OECD guidelines for the testing of chemicals,freshwater alga and cyanobacteria growth inhibiton test have been carried out.The toxicological effects of hexavalent chromium(Cr6+)on the growth of Chlorella vulgaris,Scenedesmus obliquus and Microcystis aeruginosa have been studied at different pH levels.When the value of pH is 7.0,8.0 and 9.0,taking the 72h algal biomass as the endpoint,the specific growth rates,NOEC,LOEC,EC10 and EC20 have been calculated,respectively.The results show the pH levels significantly effect the growth of alga.The optical growth pH of Chlorella vulgaris is 7.0,while that of Scenedesmus obliquus and Microcystis aeruginosa is pH=9.0;When the value of pH is 7.0,the toxicity of Cr6+ was minimum for Chlorella vulgaris.For Scenedesmus obliquus and Microcystis aeruginosa,the toxicities were minimum at pH=9.0.At the optimal growth pH value of the algae,the toxicity of Cr6+ could reach the minimum;Microcystis aeruginosa was much more sensitive to Cr6+ than Chlorella vulgari and Scenedesmus obliquus.