含磷钝化剂对镉污染农田土壤酶活性的影响  

Effects of phosphorus-containing passivators on enzyme activity in cadmium-contaminated agricultural soils

作　　者：吴春发[1] 关浩然 张锦路 张宇 WU Chun-fa;GUAN Hao-ran;ZHANG Jin-lu;ZHANG Yu(College of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学应用气象学院,江苏南京210044

出　　处：《江苏农业学报》2022年第2期361-368,共8页Jiangsu Journal of Agricultural Sciences

基　　金：国家级大学生创新训练计划项目(201910300039Z);国家重点研发计划项目(2019YFC1804704)。

摘　　要：土壤酶活性是表征土壤修复成效的重要指标,含磷钝化剂是镉污染农田土壤常用的一类钝化剂。因此,研究不同含磷钝化剂对镉污染农田土壤酶活性的影响具有重要意义。本研究选用羟基磷灰石(HAP)、磷酸二氢钙(MCP)和磷酸氢二钠(DSP)3种典型含磷钝化剂作为供试钝化剂,对镉污染农田土壤开展了为期3个月的室内钝化修复试验,并测定了镉化学形态、土壤基本理化性质以及土壤脲酶、酸性磷酸酶、过氧化氢酶、蔗糖酶的活性。结果表明,3种含磷钝化剂的添加不仅改变了土壤pH、阳离子交换量、总磷含量和有效磷含量,还促进了土壤可交换态镉向有机结合态镉和残渣态镉转化,降低了镉的活性。其中,HAP具有更好的钝化效果。HAP对脲酶活性有显著的促进作用,MCP对酸性磷酸酶活性和过氧化氢酶活性分别具有显著促进作用和抑制作用,DSP对脲酶和酸性磷酸酶的活性均有抑制作用。在所选土壤环境因子中,土壤pH和碳酸盐结合态镉含量这2个因子对供试土壤酶活性的影响相对较大。碳酸盐结合态镉含量与脲酶、蔗糖酶活性显著负相关,钝化处理可能通过降低碳酸盐结合态镉含量来提高脲酶、蔗糖酶活性;土壤pH与酸性磷酸酶活性极显著负相关,与过氧化氢酶活性极显著正相关,钝化处理可能主要通过降低(提高)pH来促进(抑制)土壤酸性磷酸酶活性,主要通过提高(降低)pH来促进(抑制)过氧化氢酶活性。从钝化效率和对土壤酶活性影响的角度综合考虑,HAP比MCP、DSP更适合用于轻度镉污染农田土壤的钝化修复。Soil enzyme activity is an important indicator to characterize the effectiveness of soil remediation,and phosphorus(P)-containing passivators are commonly used in cadmium(Cd)-contaminated farmland soils.Therefore,it is of great significance to study the effects of P-containing passivators on enzyme activity in Cd-contaminated agricultural soils.Three typical P-containing passivators including hydroxyapatite(HAP),calcium dihydrogen phosphate(MCP)and disodium hydrogen phosphate(DSP)were chosen as passivators for Cd-contaminated agricultural soils in a three-month indoor incubation experiment.Soil enzymes(urease,acid phosphatase,catalase and sucrase)activities,chemical forms of Cd and some physicochemical properties were determined.The results indicated that the application of three passivators altered soil pH,cation exchange capacity(CEC),total P content and available P content,and promoted the transformation from exchangeable Cd(Cd_(Ex))to Cd bound to organic matter(Cd_(OM))and residual Cd(Cd_(Res)),resulting in the decrease of availability of Cd.In addition,HAP had a better passivation effect than MCP and DSP.HAP significantly enhanced soil urease activity,and MCP significantly enhanced soil acid phosphatase activity and descended soil catalase activity,while soil urease and acid phosphatase activities were decreased by DSP.Two soil factors,soil pH and the content of Cd bound to carbonates(Cd_(Car)),had relatively greater effects than other factors on soil enzyme activities.The content of Cd_(Car) was significantly negatively correlated with the activities of soil urease and sucrase,and passivation treatment might improve urease and sucrase activities by reducing Cd_(Car) content.The stimulated activities of soil acid phosphatase and catalase were probably attributed to the decreased and elevated pH respectively,which had negative correlation with the former and positive correlation with the latter.Therefore,HAP is more suitable for slightly Cd-contaminated agricultural soils than MCP and DSP according to passiva

关 键 词：含磷钝化剂 钝化修复 镉污染 土壤酶活性 

分 类 号：X53[环境科学与工程—环境工程]