铜离子与铜镉离子复合污染对稻田土壤酶活性的影响研究

通过对Cu2+单一处理和铜镉复合处理条件下土壤酶活性的对比分析,研究了铜镉元素对土壤酶毒性的不同复合效应以及稻田土壤重金属污染状况与土壤酶活性的相互关系.研究结果表明,重金属复合污染不仅与单一元素污染的生物学效应不同,而且对土壤酶活性的影响也更为复杂.Cu2+单一污染对稻田土壤酶的抑制效应顺序为磷酸酶＞脲酶＞过氧化氢酶,与铜镉复合污染的抑制效应顺序脲酶＞磷酸酶＞过氧化氢酶不同.脲酶和磷酸酶对铜镉污染反应敏感,其活性与Cu2+浓度和铜镉复合浓度均呈显著负相关.铜镉复合污染对脲酶表现出协同抑制的特征;对过氧化氢酶和磷酸酶的毒性表现出不同程度的拮抗作用.建议综合脲酶和磷酸酶活性作为评价和预测稻田土壤铜镉污染的生物学指标.

Study on the effects of mono-contamination of Cu2+ and associated-contamination of Cu2+ and Cd2+ on enzyme activities in flooded paddy soil

The effects of monocontamination of Cu~(2 ) and associated-contamination of Cu~(2 ) and Cd~(2 ) on enzyme activities in flooded paddy soil were studied by analysis of soil enzyme activities.The results showed that the associated contamination of heavy metals was not only different from single element,but also the effects on soil enzyme activities were distinct.In paddy soil,Cu~(2 ) inhibited the enzyme activities in the order: phosphatase>urease>hydrogen peroxidase and differed from that of inhibition of Cu~(2 )-Cd~(2 ) associated-contamination: urease>phosphatase>hydrogen peroxidase.Urease and phosphatase activities were decreased significantly with increasing contaminations.The multivariate regression analysis indicated that urease and phosphatase activities were very obviously related to both mono-contamination of Cu~(2 ) and Cu~(2 )-Cd~(2 ) associated-contamination.The characteristics of Cu~(2 )-Cd~(2 ) associated pollution for urease exhibits synergistic effect;however,it pointed out antagonistic effect for phosphatase and hydrogen peroxidase at different levels.It suggested that it is feasible to use urease and phosphatase activities as a primary biochemical parameter to evaluate and assess heavy metals compound pollution in paddy soil.