为研究水体中典型有机污染物的环境基准,考虑环境因子对污染物生物效应的影响,选取生长速率(μ),无可观察效应浓度(NOEC),最低可观察效应浓度(LOEC)和半抑制浓度(EC50)为指标,研究了不同pH(7,8和9)对小球藻(Chlorella vulgaris)和斜生栅藻(Scenedesmus obliquus)的生长以及对对硝基酚(p-NP)毒性的影响.结果表明:pH为7～9时,小球藻和斜生栅藻均可正常生长,但各自最适生长的pH不同,小球藻的最适生长pH为8,而斜生栅藻的最适生长pH为9.p-NP对小球藻和斜生栅藻的毒性均随pH的增大而降低,pH为9时毒性最小,但p-NP对斜生栅藻的毒性比对小球藻的大,即斜生栅藻对p-NP要比小球藻更敏感.因此,在研究p-NP的水生态基准时,应该考虑pH的影响.%In order to study the environmental criteria of typical organic contaminants in aquatic systems, the influence of environmental factors on their biological effects was considered. End points of growth rate (μ), NOEC, LOEC and EC50 were selected as evaluation indices to study the growth of Chlorella vulgaris and Scenedesmus obliquus, and the p-nitrophenol (p-NP)toxicity to them at pH levels 7, 8 and 9. The results showed that both Chlorella vulgaris and Scenedesmus obliquus could grow well at the range of pH 7-9, but the most suitable pH condition was different for each of them. Chlorella vulgaris grew best at pH 8,while Scenedesmus obliquus grew best at pH 9. The toxicity of p-NP to Chlorella vulgaris and Scenedesmus obliquus decreased with increasing pH, and the least toxic effect was observed at pH 9. The p-NP was more toxic to Scenedesmus obliquus than Chlorella vulgaris, that is, Scenedesmus obliquus was more sensitive to the toxicity of p-NP than Chlorella vulgaris. Therefore, the influence of pH should be considered when an aquatic ecological criteria of p-NP are selected.
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