摘要
在拉萨市3个典型功能区各采集9个土样(共27个),采样深度0～20cm,对土壤中As、Hg、Cr等7种重金属元素含量进行测定,并进行重金属空间分布特征分析,采用单因子污染指数法对环境中的主要污染因子的污染程度进行判断,然后用潜在生态风险指数法对其潜在的生态危害进行评价,以期掌握拉萨市周边不同功能区农田土壤重金属污染状况,以期为当地制定合理的土壤重金属修复策略,适时调整农作物种植方式提供依据。结果表明:通过与西藏重金属背景值的比较,样品中As的富集最为严重,As的污染分担率为62.7%,94.4%的土壤样品符合国家土壤环境质量二级标准;样点土壤中重金属的潜在生态风险指数大小顺序为As>Cr>Cu>Pb>Ni>Zn,不同研究区生态风险指数大小为拉萨市郊区农田>工业产业区>设施园艺栽培区,仅拉萨市次角林乡农田土壤处于中等生态风险水平,其余采样点处于微弱生态风险水平。拉萨市不同功能区农田土壤重金属含量总体呈下降趋势,部分超标农田土壤主要受重金属As污染,农田土壤重金属总体潜在生态危害程度为轻微。
In order to find out the pollution characteristics of heavy metals in different functional farmland surrounding Lhasa city,and provide evidence for making reasonable repairing strategy for soil heavy metals and adjusting the planting mode of the crops timely.27 soil samples were collected from 3 different functional area of the Lhasa city（the sampling depth was 0-20 cm）,and the contents of As,Hg,Cd,Pb,Cr,Cu,Zn were determined,then analyzed the spatial distribution,the pollution level of the main pollution factors in environment were evaluated with single pollution index,then assessed the ecological hazard with potential ecological risk index.Compared with the Tibet soil heavy metals background values,the experiment found that As element was enriched most serious in soil sample,and its pollution share rate reached 62.7%,at the same time,the ratio of soil quality which was below soil environmental quality standard class Ⅱwas 94.4%.The potential ecological risk of heavy metals were in order of As〉Cr〉Cu〉Pb〉Ni〉Zn,the ecological risk of different functional farmland were farmland of Lhasa suburbs〉industry areas〉facility horticulture areas,except the farmland soil in Cijiaolin county was at medium risk level,the rest sample at slight risk level.The heavy metals in different functional farmland of Lhasa city was downtrend,parts of contaminated soil was determined by As element,on the whole,the potential ecological risk of heavy metals was slight.
作者
孙全平
SUN Quanping(Institute of Agricultural Resources and Environment,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa,Tibet 85000)
出处
《北方园艺》
CAS
北大核心
2018年第22期124-129,共6页
Northern Horticulture
基金
西藏自治区自然科学基金资助项目(13-50)
西藏自治区科技重大专项资助项目(Z2016B01N01-03-03)
关键词
拉萨市
土壤重金属
生态风险
潜在风险评价
Lhasa city
soil heavy metals
ecological risk
potential risk assessment
