外源秸秆对污染土壤氧化还原过程水分散性胶体态重金属的影响  

Effect of Exogenous Rice Straw on Water Dispersible Colloidal Metals in Polluted Soil under Redox Change

作　　者：张雨 汪家家 夏冰 罗雪婷 胡鹏杰[1] 吴龙华[1] 骆永明[1] ZHANG Yu;WANG Jiajia;XIA Bing;LUO Xueting;HU Pengjie;WU Longhua;LUO Yongming(Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;Department of Environmental Science and Engineering,Fudan University,Shanghai 200438,China;Anhui Academy of Eco-Environmental Science Research,Hefei 230041,China)

机构地区：[1]中国科学院土壤环境与污染修复重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院大学,北京100049 [3]复旦大学环境科学与工程系,上海200438 [4]安徽省生态环境科学研究院,合肥230041

出　　处：《土壤学报》2024年第1期163-173,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41977135);安徽省自然科学基金项目(200805MD107)资助。

摘　　要：土壤胶体尤其是水分散性胶体,作为一种重要的污染物载体,在重金属吸附、迁移以及生物吸收过程起着重要作用。通过土壤培养试验探讨了外源添加水稻秸秆在氧化还原波动条件下如何影响土壤液相中及水分散性胶体中重金属的分布。结果表明,外源秸秆增加厌氧过程液相中溶解性有机碳(DOC)、砷(As)、铁(Fe)、锰(Mn)、钙(Ca)、钾(K)、硅(Si)、铝(Al)、镁(Mg)等浓度,降低了厌氧过程氧化还原电位(Eh)及铜(Cu)、铅(Pb)等浓度,提高了好氧过程Pb浓度。利用非对称流场流分馏-紫外可见-电感耦合等离子体-质谱联用技术(AF4-UV-ICP-MS),测得水分散性胶体颗粒主要分布在0.3~3 kDa、3~40 kDa和130 kDa~450 nm三个粒径范围,各粒径颗粒的组成有所差异,主要含有机质、无机黏土矿物和铁矿物等。外源秸秆促进液相中Fe和As由胶体态向溶解态转化,促进镉(Cd)和Cu由溶解态向胶体态转化。本研究有助于揭示农业活动影响重金属迁移转化及有效性的界面机制。【Objective】Soil colloids,especially water-dispersible colloids(WDC),as pollutant carriers,play important roles in heavy metal adsorption,migration,and biological absorption.The purpose of this study was to explore the effect of exogenous rice straw and redox change on the distribution of heavy metals in the aqueous phase of the soil and water-dispersible colloids.【Method】In this study,soil microcosm experiments were conducted for 70 days,in which 0-40 days was the reduction period,and 41-70 days was the oxidation period.The experiment comprised two treatments:(i)no straw added(CK),(ii)rice straw added(1%of the soil weight,S).The different chemical parameters in the aqueous phase of the soil were comprehensively compared,and the particle size classification and elemental composition of WDC during the redox process were characterized by asymmetrical flow field-flow fractionation(AF4)coupled to UV and ICP-MS(AF4-UV-ICP-MS)method.【Result】The results showed that in anaerobic conditions,exogenous rice straw increased aqueous concentrations of dissolved organic carbon(DOC),arsenic(As),iron(Fe),manganese(Mn),calcium(Ca),potassium(K),silicon(Si),aluminum(Al),and magnesium(Mg),while it decreased aqueous redox potential(Eh)and the concentrations of copper(Cu)and lead(Pb).In aerobic conditions,exogenous rice straw increased aqueous concentrations of Pb.Results from AF4-UV-ICP-MS indicated that the size of WDC was mainly distributed at three size ranges,0.3-3 kDa,3-40 kDa,and 130 kDa-450 nm with different complexes of organic matters,inorganic clay minerals,and ferriferous minerals.A significant proportion of heavy metals in the aqueous phase were bound to WDC particles,which indicated that WDC played an important role in the environmental behavior of these pollutants.WDC with different particle sizes tended to combine different kinds of heavy metals.Exogenous rice straw affected the distribution of heavy metals in WDC particles and this effect was related to the nature of the elements.Also,exogenous rice straw pr

关 键 词：土壤胶体 重金属 水稻秸秆 氧化还原 水分散性胶体 场流分馏 

分 类 号：X53[环境科学与工程—环境工程]