基于土壤酶活性变化的铅污染土壤修复基准

近年来,污染土壤修复技术发展很快,而污染土壤修复标准的建立则相对迟缓。为了推进我国该领域的工作,对铅胁迫下土壤酶活性（如过氧化氢酶,磷酸酶,脲酶）随时间的变化进行了研究,以确定棕壤土中铅的土壤修复基准。结果表明：土壤中的铅能够刺激土壤中过氧化氢酶活性的增加,但随着土壤铅浓度的增加,这种刺激作用逐渐减小。土壤过氧化氢酶活性不宜作为铅污染土壤的生物标记物。土壤磷酸酶活性没有一致的变化规律,土壤磷酸酶活性不能作为铅污染土壤的生物标记物。在整个实验时间范围内,土壤脲酶活性与土壤中铅的浓度具有明显的剂量-效应关系（P〈0.01）,土壤脲酶活性可以作为铅污染土壤生物标记物。以土壤脲酶抑制率降低25%为依据,确定棕壤中铅的土壤修复基准为94mg·kg-1,以土壤脲酶抑制率降低45%为依据,确定棕壤中铅的土壤修复基准为178mg·kg-1。

Probabilistic remediation criterions of contaminated soil for lead derived from soil enzyme activities

Remediation technology for contaminated soils is being developed rapidly in recent years,but establishment of polluted soil remediation criterion is developed slowly.In order to accelerating the work in this field,the changes of soil enzyme activities（such as catalase,phosphatase and urease）with the time under the menace of lead were studied to obtain a remediation criterion for lead in soil.Results showed that the existence of lead in soil stimulated the increasing of the activities of catalase in soil.With the increasing of concentration of lead the stimulation was decreased little by little.The activities of catalase in soil was not suitable as the biomarkers of lead.The activities of phosphatase in soil had no uniform change rule with lead in soil and it could not be consid-ered as biomarkers of stress by Pb in soil.During the whole experiment time there are dose-response relationships（p0.01）between the activities of urease in soil and the concentration of lead in soil.The activities of urease in soil could be considered as biomarkers of stress by lead.With the point where activities of urease dropped by 25% set as the critical point for soil lead pollution in brown soil,the critical value is 94 mg·kg^-1 for lead.And with the point where activities of urease droped by 45% set as the critical point for soil lead pollution in brown soil,the critical value is 178 mg·kg^-1.