一氯苯对土壤脲酶活性特征的影响

Effect of monochlorobenzene on soil urease activity characteristics

【目的】研究一氯苯对土壤脲酶活性特征的影响,为环境保护和监测提供参考依据。【方法】以土娄土和红壤为研究对象,采用室内模拟方法,研究不同体积分数(0,0.5%,1.0%,2.5%,5.0%和10%)一氯苯对土壤脲酶活性及酶促反应动力学特征参数(Vmax,Km和k)的影响。【结果】一氯苯对土壤脲酶有明显的激活作用,其中4个土样脲酶活性与一氯苯体积分数间的关系可以用线性方程进行拟合。供试土壤轻度污染时的一氯苯临界浓度为34.0g/kg。随一氯苯体积分数的增大,土娄土的最大反应速率Vmax增大,Vmax/Km、Km和k的变化规律性不明显,红壤的各特征参数受一氯苯的影响较小。【结论】土壤脲酶在一定范围内可表征红壤受一氯苯污染的程度;一氯苯加速了土娄土脲酶和尿素复合物的解离;一氯苯与土壤脲酶之间的关系较为复杂,其机理有待进一步研究。

[Objectiye] The relationship between monochlorobenzene and soil urease activity characteristics was studied in order to supply basis for environmental protection and mointor. [Method] An indoor simulation experiment was carried out to study the effect of different monochlorobenzene concentrations （0,0.5% ,1.0% ,2.5%,5.0% and 10%） on urease activity and urease kinetic parameters of Lou soil and red soil. [Result] Monochlorobenzene could activate soil urease activity significantly and the equation of U=β1 ）〈 C＋β0 could well describe their relationship in four soil samples. Meanwhile,the critical concentration was 3.4 % when soils were slightly polluted by monochlorobenzene. The kinetic parameter Vmax of LOU soil increased as the concentration of monochlorobenzene added. The Vmax/Km and k did not change remarkably,and the monochlorobenzene had little impact on red soil enzyme kinetic parameters. [Conclusion] Soil urease activities could be an index of soil polluted by monochlorobenzene. Monochlorobenzene could accelerate the dissociation of enzyme-substrate complex. There was a complex interaction between Monochlorobenzene and urease,which needs further study.