宁夏不同生态区土壤-作物系统重金属风险评估  

Health Risk Assessment of Heavy Metals in Soil-crop System in Different Ecological Regions of Ningxia

作　　者：陈林 李虹[4] 马建军 王金保 王君梅 梁翔宇 贾彪 庞丹波[1,2,3] 薛斌 马琨 CHEN Lin;LI Hong;MA Jian-jun;WANG Jin-bao;WANG Jun-mei;LIANG Xiang-yu;JIA Biao;PANG Dan-bo;XUE Bin;MA Kun(Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education,Ningxia University,Yinchuan 750021,China;Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China,Ningxia University,Yinchuan 750021,China;School of Ecology and Environment,Ningxia University,Yinchuan 750021,China;Agriculture Environmental Protection Monitoring Station of Ningxia,Yinchuan 750002,China;School of Agriculture,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学西北退化生态系统恢复与重建教育部重点实验室,银川750021 [2]宁夏大学西北土地退化与生态恢复国家重点实验室培育基地,银川750021 [3]宁夏大学生态环境学院,银川750021 [4]宁夏农业环境保护监测站,银川750002 [5]宁夏大学农学院,银川750021

出　　处：《环境科学》2024年第12期7209-7217,共9页Environmental Science

基　　金：宁夏农业资源环境监测与保护项目(2130135);宁夏自然科学基金项目(2023AAC03061);第三批宁夏青年科技人才托举工程项目(TJGC2018068)。

摘　　要：重金属具有毒害性、不可生物降解性以及在食物链中积累性等特征,因此农田土壤重金属分布和作物安全备受关注.2017~2021年共采集宁夏农田土壤样品和作物样品1274个,采用生物富集系数、生态风险指数、相关性分析等方法,开展了宁夏土壤-作物系统重金属含量特征及健康风险评估研究.结果表明,研究区土壤呈碱性,机械组成以粉粒和砂粒为主.土壤中重金属含量由高到低为:Zn>Cr>Ni>Cu>Pb>As>Cd>Hg,除Cu和Ni外,北部地区土壤中重金属含量均高于中部和南部地区.土壤重金属低、中生态风险指数等级点位比例较高(98.58%),说明土壤环境总体良好.作物中8种重金属平均含量均未超过限量值,而且平均健康风险指数值<1,但个别作物中As的健康风险指数有>1的点位.从生物富集系数来看,作物对As、Cd、Cr、Cu、Ni、Pb和Zn等重金属没有积累效应,虽然作物对Hg的平均吸收并未表现出积累,但有31个作物表现出一定的累积,需要引起重视.除作物中的As和Ni与土壤中的Cu含量有较弱的相关性外,作物中其他重金属与相应的土壤重金属没有显著相关性,说明作物中的重金属含量受土壤重金属的影响较小.RDA分析表明,砂粒含量与Hg、Ni、Pb和Cd等重金属转移系数具有较强的正相关关系,粉粒含量则呈较强的负相关关系,土壤较高的pH值减弱了重金属向作物的转移富集.综上所述,研究区土壤环境和作物质量总体良好.但仍需要关注重金属含量较高或超标准值的点位,建立长期的作物产地土壤和农产品质量状况监测是很有必要的管控举措.Heavy metals are characterized by toxicity,non-biodegradability,and accumulation in the food chain;hence,o the distribution of heavy metals in farmland soils and crop food safety have attracted much attention.A total of 1274 soil samples and crop samples were collected from farmland in Ningxia from 2017 to 2021 and bioconcentration coefficients were used based on the analysis of the elemental contents of Zn,Cr,Ni,Cu,Pb,As,Cd,and Hg.The ecological risk index and correlation analysis were used to characterize the heavy metal content and health risk assessment of the soil-crop system in Ningxia.The results showed that the soils in the study area were alkaline and the mechanical composition was dominated by pulverized and sandy grains,with a relatively small content of clay grains.The heavy metal contents in the soils were in the following order:Zn>Cr>Ni>Cu>Pb>As>Cd>Hg.Except for that of Cu and Ni,the contents of other heavy metals in the soils of the northern region were higher than those of the central and southern regions.The ecological risk index of soil heavy metals was Hg>Cd>As>Cu>Pb>Ni>Cr>Zn and the proportion of points with low and medium ecological risk index levels was high(98.58%),indicating that the soil environment was generally good.The average content of the eight heavy metals in crops did not exceed the limit value,and the average health risk index value was<1.However,the health risk index(HRI)of As in individual crops existed at points>1 in all three sub-regions and individual points with high values of HRI(HRI>1)for Cu and Ni were observed in crops in the northern region and for Pb in the north and south of the country,which require further attention.From the bioconcentration factor,crops showed no accumulation effect(BCF<1)for heavy metals such as As,Cd,Cr,Cu,Ni,Pb,and Zn and although the average uptake of Hg by crops did not show accumulation,a total of 31 crops in the three ecological zones showed some accumulation(BCF>1),which also requires further monitoring.Analysis using the Mantels test show

关 键 词：土壤-作物系统 重金属 健康风险评价 Mantel检验 宁夏 

分 类 号：X171.5[环境科学与工程—环境科学]