摘要
城市土壤中各种重金属的含量受人为活动的强烈影响,且城市建成区和非建成区人口密度和人类活动等差异显著.因此,城市土壤背景值的确定可能不同于非城市土壤,但目前相关研究短缺.为此,本研究选取北京市土壤中砷、镉、铬、铜、汞、镍、铅和锌等重金属为重点研究对象,研究近30年来北京市建成区和非建成区表层(0~20 cm)土壤重金属的时空变化规律及影响因素.结果表明,除受人为活动影响外,表层土壤中重金属含量与土壤理化性质相关,粒径较小、有机碳含量和阳离子交换量较高的土壤重金属含量较高.2019年北京市建成区表层土壤中铜和汞含量显著高于非建成区(p<0.05).近10年来,北京市建成区表层土壤重金属含量呈下降趋势;但近30年来,非建成区表层土壤重金属含量呈上升趋势.尽管采样点都远离了明显的污染源,但建成区和非建成区表层土壤重金属的时空分布存在明显差异,因此,需要分别研究建成区和非建成区的土壤背景值,在建成区远离明显污染源采样点所获得的重金属元素含量可以作为建成区土壤的背景值,用于评价城市建成区土壤是否受工厂、企业、加油站和交通等明显污染源的影响.研究结果为获取城市建成区土壤重金属背景值提供了方法参考,为城市土壤重金属质量标准的制定提供了科学依据.
The content of heavy metals in city soil is strongly affected by human activities,and the population density and human activities are significantly different between urban areas and suburban areas of cities.Therefore,the background values of city soil may be different from that of other soil,however,the limited study focus on the background values of city soil.The study chose the heavy metals such as As,Cd,Cr,Cu,Hg,Ni,Pb and Zn in the soil of Beijing as research objects to understand the spatiotemporal changes and influencing factors of heavy metals in topsoil(0~20 cm)of urban and suburban areas in Beijing.The results indicated that the content of heavy metals in topsoil was related to soil physicochemical properties in addition to the influence of human activities;the content of heavy metals was higher in the soil with smaller particle size,higher organic carbon content and cation exchange capacity.The content of Cu and Hg in the topsoil of the urban areas of Beijing was significantly higher than those in suburban areas(p<0.05).The content of heavy metals decreased in the topsoil of urban areas in Beijing over the past decades,however,the concentrations of heavy metals increased in the topsoil of suburban areas over the past three decades.Although the sampling sites were far from obvious pollution sources,the spatiotemporal distribution of heavy metals was significantly different between urban areas and suburban areas in Beijing,which indicated that it is necessary to study the background values of soil in urban and suburban areas respectively.The content of heavy metals from the sampling sites which were far from obvious pollution sources in urban areas can be regarded as the background value of the soil in urban areas to evaluate the influence of pollution sources such as factories,enterprises,gas stations and traffic.This study provides a reference method for obtaining the soil background value of urban areas and a scientific basis for the establishment of heavy metal quality standard in urban soil.
作者
夏星辉
张真瑞
张效颖
唐振强
李雅媛
邹本东
荆红卫
李凯璇
张青
刘少达
XIA Xinghui;ZHANG Zhenrui;ZHANG Xiaoying;TANG Zhenqiang;LI Yayuan;ZOU Bendong;JING Hongwei;LI Kaixuan;ZHANG Qing;LIU Shaoda(State Key Laboratory of Water Environment Simulation,Key Laboratory of Hydrology and Sediment Science,Ministry of Education,School of Environment,Beijing Normal University,Beijing 100875;Beijing Municipal Pollution Source Management Center,Beijing 100089;Beijing Municipal Ecological and Environmental Monitoring Center,Beijing 100048)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第3期438-447,共10页
Acta Scientiae Circumstantiae
基金
国家重点研发计划(No.2017YFA0605001)。
关键词
土壤
重金属
背景值
建成区和非建成区
城市
北京
soil
heavy metals
background values
urban and suburban areas
city
Beijing
