桂西北岩溶地质高背景和矿业活动叠加区土壤剖面镉分布特征及生物有效性  

Distribution Characteristics and Bioavailability of Cadmium in Soil Profile from Karst High Geological Background and Mining Activities Superimposed Pollution Area of Northwest Guangxi,China

作　　者：王艺惠 文鑫 钟聪 朱槟栾 苏丹妮 王成[3,4] WANG Yi-hui;WEN Xin;ZHONG Cong;ZHU Bing-luan;SU Dan-ni;WANG Cheng(Key Laboratory of Environment Change and Resources Use in Beibu Gulf of Ministry of Education/Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation,Nanning Normal University,Nanning 530001,Guangxi,China;Institute of Geography and Oceanography,Nanning Normal University,Nanning 530001,Guangxi,China;School of Environmental Science and Engineering,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China;Jiangsu Key Laboratory of Atmospheric Environment Monitoring&Pollution Control,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南宁师范大学北部湾环境演变与资源利用教育部重点实验室/广西地表过程与智能模拟重点实验室,广西南宁530001 [2]南宁师范大学地理与海洋研究院,广西南宁530001 [3]南京信息工程大学环境科学与工程学院,江苏南京210044 [4]南京信息工程大学江苏省大气环境监测与污染控制高技术研究重点实验室,江苏南京210044

出　　处：《地球科学与环境学报》2024年第1期81-95,共15页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(41867049);广西自然科学基金项目(2018GXNSFAA281263,2016GXNSFBA380106)。

摘　　要：桂西北岩溶地质高背景与矿业活动叠加,导致土壤污染风险增大,对粮食和生态安全构成了潜在威胁。以广西河池地区典型岩溶地质高背景与矿业活动叠加区作为研究区域,采集了3条水稻田土壤剖面(0~100 cm)样品,分析镉(Cd)的空间分布特征和生物有效性,结合富集因子法、风险评价指数等对土壤剖面Cd污染状况与生态风险进行了评估。结果表明:3条剖面土壤Cd在表层(0~20 cm)均显著富集,表明在土壤表层有明显人为来源的重金属Cd积累。根据国家标准《土壤环境质量:农用地土壤污染风险管控标准(试行)》(GB 15618—2018),距离矿区较远的两条剖面土壤Cd含量有个别样品超过农用地土壤污染风险筛选值,而靠近矿区的剖面则有90%的土壤样品超过农用地土壤风险管控值。研究区土壤剖面Cd含量主要受控于地质背景、农业耕作和矿业活动等多因素相互叠加,不同剖面含量差异主要取决于距离矿区的远近,同一剖面则与土壤pH值和有机质含量有关。土壤剖面Cd主要以铁锰结合态、离子交换态和残渣态存在,其生物有效性主要受控于土壤Cd总含量、pH值、有机质含量以及铁锰氧化物的固定作用,表现出远离矿区的土壤剖面以及土壤表层的生物有效性相对较高的特点。The combination of karst high geological background and mining activities in northwest Guangxi leads to increase soil pollution risk,which poses a potential threat to food and ecological security.Study on the spatial distribution characteristics and bioavailability of cadmium(Cd)in soil profiles in this region can effectively assess the pollution status and ecological risk of Cd in soil.Soil samples were collected from rice field profiles(0-100 cm)at three different positions within Dachang mining area,located in the typical karst region of Nandan county,Hechi city,Guangxi.The distribution characteristics and bioavailability of Cd in soil profiles were analyzed,and the ecological risk and pollution status of Cd in three soil profiles were evaluated by using the enrichment index method and risk assessment index.The results show that the vertical distributions of Cd contents are different among the three soil profiles,and the soil Cd is significantly enriched in the surface(0-20 cm),with 86.7% of samples showing soil enrichment factor values over 2,indicating that there is obvious accumulation of heavy metal Cd from human sources in the soil surface.According to Soil Environmental Quality:Risk Control Standard for Soil Contamination of Agricultural Land(GB 15618—2018),the Cd contents of some samples in the two soil profiles far from the mining area exceed the screening value of soil pollution risk of agricultural land,and in the soil profile adjacent to the mining area,the Cd contents of 90% soil samples surpass the pollution risk control value for agricultural land.The Cd content of soil profiles in the study area is mainly controlled by the superimposed effects of multiple factors such as geological background,agricultural cultivation and mining activities.The difference in the content of soil profiles mainly depends on the distance to the mining area(the closer the distance to the mining area,the higher the Cd content),while the same profile is primarily influenced by pH value and organic matter content.The Cd

关 键 词：重金属 镉 土壤剖面 富集特征 形态分布 生物有效性 岩溶地区 广西 

分 类 号：X53[环境科学与工程—环境工程]