重金属和多环芳烃复合污染对土壤酶活性的影响及定量表征

以土壤脲酶和脱氢酶为探针物质，室内培养条件下较为系统地研究了重金属（Cd、Zn、Pb）和多环芳烃（菲、荧蒽、苯并a芘）复合污染对土壤酶活性的影响及其定量表征、结果表明，复合投加上述污染物能使土壤酶活性受到不同程度的抑制，其中，脱氢酶最为敏感，其活性是表征重金属和多环芳烃复合污染的一项重要的参考指标．对复合污染模型的建立与分析表明，土壤环境中，重金属和多环芳烃复合污染的类型和强度与污染物的浓度和复合污染时间密切相关．影响土壤脲酶活性的主要因子依次为：Cd〉Zn与苯并a芘的交互作用〉Zn〉Pb〉Zn和菲的交互作用，影响土壤脱氢酶活性的主要因子依次为：Cd和Zn的交互作用〉Cd〉Zn〉苯并a芘〉Cd和菲的交互作用，其中，Zn和苯并a芘相互作用对脲酶活性以及Cd和Zn交互作用对脱氢酶活性的影响均表现为拮抗作用，Zn和菲，Cd和菲之间的交互作用，无论是对脲酶还是脱氢酶均表现为协同作用，图1表3参18

QUANTITATIVE EXPRESSION AND EFFECT OF COMBINED POLLUTION OF HEAVY METALS AND POLYCYCLIC ACROMATIC HYDROCARBONS ON SOIL ENZYME

Quantitative expression and effect of combined pollution of heavy metals (Cd, Zn, Pb) and polycyclic aromatic hydrocarbons (PAHs), including phenanthrene, fluoranthene and benzo(a)pyrene, on soil enzyme were investigated during 7 weeks of incubation. The result showed that the effects of heavy metals and PAHs on soil enzyme were strongly dependent on the time of pollution. Dehydrogenase appeared to be more sensitive than urease. Prominent factors affecting urease and dehydrogenase activity were proved to be Cd > Zn-benzo(a)pyrene > Zn > Pb > Zn-phenanthrene, and Cd-Zn > Cd > Zn > benzo(a)pyrene > Cd-phenanthrene, respectively. It was derived from this study that the combined effects of Zn-benzo(a)pyrene on urease and Cd-Zn on dehydrogenase were antagonistic. However, Zn-phenanthrene and Cd-phenanthrene were synergistic. Fig 1, Tab 3, Ref 18