摘要
巴嘎雪湿地是西藏拉萨河流域的代表性湿地之一.文章为了解巴嘎雪湿地的重金属分布特征,在2018年10月采集了巴嘎雪湿地的表层土壤样品,对土壤中的Cu、Zn、Cr、Ni、Pb、Cd、As、Hg重金属的含量进行了检测.巴嘎雪湿地表层土壤的重金属污染评价采用的方法主要包括内梅罗综合污染指数法、地积累指数法和潜在生态风险指数法.结果表明,重金属Cu、Zn、Cr、Ni、As、Hg含量的平均值低于国家土壤环境质量标准(一级),但Pb、Cd的含量略偏高;Ni、As、Cr、Hg的平均含量低于拉萨市环境背景值,但Cu、Zn、Pb、Cd平均含量高于环境背景值.该研究区域的内梅罗综合污染指数平均值P_(N)=1.50,说明湿地整体处于轻度污染;按照国家土壤环境质量标准(二级)作为背景值,得到的P_(N)=0.64,属于安全水平.地积累指数平均值在-2.587到-0.744范围内,I_(geo)<0区域整体上无污染;潜在生态风险指数的平均值RI=72.779,属于低风险.各元素组合之间总体相关性不足,说明重金属累积方式具有多源性特点.巴嘎雪湿地整体生态环境优于国内大部分湿地,其表层土壤中Hg、Pb、Cd元素为强度变异,在部分位点中存在明显富集,受到人类活动影响,应加强关注.
Bagaxue wetland is one of the representative wetlands in the Lhasa River Basin of Tibet. Surface soil samples of the Bagaxue wetland were gathered in October 2018, and then detected the contents of heavy metals such as Cu, Zn, Cr, Ni, Pb, Cd, As and Hg in soil so as to understand the distribution characteristics of heavy metals in the Bagaxue wetland. The mainly methods used for heavy metal pollution assessment include Nemerow comprehensive pollution index method, Geo-accumulation index method and Potential ecological risk index method. The results indicated that the average contents of Cu, Zn, Cr, Ni, As and Hg were lower than the first grade of the environmental quality standard for soils(GB 15618—1995), while the contents of Pb and Cd were higher. Meanwhile, it was concluded that the average contents of Ni, As, Cr, Hg were lower than the environmental background value of Lhasa, whereas the average contents of Cu, Zn, Pb, Cd were higher. The mean value of the Nemerow comprehensive pollution index P_(N) in study area was 1.50, which manifested that the wetland as a whole was in light pollution. According to the second grade of environmental quality standard for soil(GB 15618—1995) as the background value, the calculated P_(N) was 0.64, which belonged to the safety level. The average value of Geo-accumulation index was within the range of-2.587 to-0.744, and I_(geo)<0 indicated that the region as a whole was pollution-free. The average RI of the potential ecological risk index was 72.779, which belonged to low risk. The overall correlation among elements combinations was insufficient, which indicated that the heavy metal accumulation mode was multi-source. In short, the overall ecological environment of Bagaxue wetland was better than that of most wetlands in China. Hg, Pb and Cd elements in the surface soil had strength variation and obvious enrichment in some sites, which were affected by human activities and should be paid more attention to.
作者
李伟
布多
孙晶
单再毅
吕学斌
熊健
LI Wei;BU Duo;SUN Jing;SHAN Zaiyi;LV Xuebin;XIONG Jian(College of Science,Tibet University,Lhasa,850000,China)
出处
《环境化学》
CAS
CSCD
北大核心
2021年第1期195-203,共9页
Environmental Chemistry
基金
中央支持地方高校改革发展专项资金(藏财教指[2018]54号)
环境化学与生态毒理学国家重点实验室开放基金(KF2017-07)
西藏大学培育基金(ZDCZJH18-08)
西藏大学大学生创新项目(2018XCX009)
西藏经济社会发展与高原科学研究共建创新基金专项项目(lzj2020002,lzt2020002)资助。
关键词
巴嘎雪湿地
重金属
生态风险评价
拉萨河流域
Bagaxue wetland
heavy metals
ecological risk assessment
Lhasa River basin
