西南典型地质高背景区与矿业活动区稻田土壤剖面镉分布特征及生物有效性研究  

Cadmium Distribution and Bioavailability in Paddy Soil Profiles from Regions Impacted by High Geochemical Background and Mining Activities,Southwestern China

作　　者：王莹 刘意章[1] 张永祥 黎宇洋 景璟 周旺旺 宁增平[1] 刘承帅 WANG Ying;LIU Yizhang;ZHANG Yongxiang;LI Yuyang;JING Jing;ZHOU Wangwang;NING Zengping;LIU Chengshuai(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Resources and Environment,Changjiang University,Wuhan 430100,China)

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京100049 [3]长江大学资源与环境学院,武汉430100

出　　处：《地球与环境》2025年第1期34-43,共10页Earth and Environment

基　　金：国家自然科学基金项目(42373065、42330712);中国科学院青年创新促进会(2021399)。

摘　　要：我国西南地质高背景区与矿业活动区的稻田土壤镉普遍富集,而不同来源镉的活性与风险差异较大,目前对不同成因高镉稻田土壤剖面的对比研究较少。本研究比较了贵州南部地质高背景区和矿业活动区稻田土壤剖面的镉含量、赋存形态和生物有效性的纵向分布特征及主要影响因素。结果表明,地质高背景区土壤镉含量随深度变化小,而矿业活动区土壤镉含量随深度增加而降低。铁锰氧化物结合态和可交换态是研究区土壤中镉的主要赋存形态,矿业活动区土壤可交换态镉占比约为地质高背景区土壤的2倍,且生物有效态镉占比(13.6%)高于地质高背景区土壤(7.76%)。地质高背景区土壤镉的生物有效性受土壤有机质、游离铁氧化物等因素影响,而矿业活动区土壤镉的生物有效性主要受来源影响,活性态镉向下迁移导致深层土壤镉的生物有效性升高。这些研究结果可为喀斯特区不同成因高镉稻田土壤的污染管控提供依据。Paddy soils in the high geochemical background and mining activity areas of Southwest China generally exhibit cadmium(Cd)enrichment,with significant differences in the activity and risk of Cd from different sources.However,comparative studies on paddy soil profiles with high Cd content from different origins are scarce.This study compared the vertical distribution and main influencing factors of Cd content,chemical forms,and bioavailability in paddy soil profiles from high geochemical background and mining activity areas in southern Guizhou.The results show that Cd content in high geochemical background soils changed little with depth,while in mining activity areas,Cd content decreased with increasing depth.In the study area,Cd primarily occurred in the forms bound to iron and manganese oxides and in exchangeable forms.The proportion of exchangeable Cd in mining activity area soils was about twice that in high geochemical background soils,and the proportion of bioavailable Cd(13.6%)is higher than in high geochemical background soils(7.76%).The bioavailability of Cd in high geochemical background soils is influenced by factors such as soil organic matter and free iron oxides,whereas in mining activity areas,the source of Cd mainly affects its bioavailability.The downward migration of active Cd increased the bioavailability of Cd in deeper soils.These findings provide a basis for pollution control of high-Cd paddy soils of different origins in karst areas.

关 键 词：喀斯特区 土壤污染 重金属 赋存形态 迁移富集 

分 类 号：X142[环境科学与工程—环境科学] X53