机构地区:[1]天津师范大学地理与环境科学学院,天津300387 [2]天津师范大学天津市水资源与水环境重点实验室,天津300387 [3]中国科学院生态环境研究中心,城市与区域生态国家重点实验室,北京100085
出 处:《中国环境科学》2020年第10期4557-4567,共11页China Environmental Science
基 金:国家重大研究计划项目(91644104);天津市研究生科研创新项目(2019YJSS121);国家自然科学基金项目(41172315);天津市水资源与水环境重点实验室开放基金项目。
摘 要:为了解西藏河流-湖泊体系沉积物重金属的污染特征、空间分布、潜在来源及生态风险,对西藏中部河流、湖泊表层沉积物及其周边土壤中As、Ba、Cd、Co、Cr、Cu、Hg、Mn、Mo、Ni、Pb、Sb、V、Zn、Al和Fe 16种重金属总量进行了分析,并利用主成分分析-绝对主成分分数-多元线性回归(PCA-APCS-MLR)受体模型定量解析了重金属的潜在来源.描述性统计分析表明,研究区As、Cd、Hg、Ni含量较高,其中Hg和As污染较为严重;富集因子、地累积指数、污染负荷指数均表明研究区Hg污染较重,其次是As、Cd、Ni;平均沉积物质量基准系数法与潜在生态风险指数结果表明,研究区受Hg、As、Cd、Ni污染,其中Hg污染较重.在空间分布方面,污染相对较重的区域主要集中在昂仁金错、堆龙曲及一些封闭型湖泊,其中As污染范围最广.PCA-APCS-MLR分析表明,沉积物重金属主要有3个来源,分别为自然来源、交通运输和大气传输以及地热活动和矿山开采等;Co、Cr、Cu、Hg、Mn、Ni、V、Zn、Al和Fe主要受自然因素影响;Ba、Mo、Pb主要受交通运输和大气传输影响;As几乎全部来自地热活动和矿山开采;Cd、Sb来源较为广泛,3个主要来源均有占比.土壤中Cd、Hg含量较高,可能受交通因素影响较大,同时还与工业排放后远距离输送所造成的大气污染有关.To understand the pollution characteristics,spatial distribution,potential sources and ecological risk of heavy metals in the surface sediments of river-lake system in Tibet,the total amounts of 16heavy metals(As,Ba,Cd,Co,Cr,Cu,Hg,Mn,Mo,Ni,Pb,Sb,V,Zn,Al and Fe)of rivers,lakes and their surrounding soils in central Tibet were determined.The potential sources of heavy metals were preliminarily apportioned and identified by principal component analysis-absolute principal component score-multiple linear regression(PCA-APCS-MLR)receptor model.Descriptive statistics showed that As,Cd,Hg and Ni accumulated and presented as severe pollutants in sediments of study area,especially for Hg and As.Enrichment factor,geo-accumulation index and pollution load index all indicated that there were moderate pollutions for Hg,followed by As,Cd and Ni.Mean sediment quality guideline quotient and comprehensive indexes of potential ecological risks showed that Hg,As,Cd and Ni exhibited the moderate potential ecological risks,among which Hg exhibited the highest risks.Spatially,the relatively serious contaminated areas were the Lake Angrenjincuo,Duilong Qu and adjacent lakes,and As displayed a widest spatial pattern.PCA-APCS-MLR revealed that the three main sources of heavy metals in sediments in the central Tibet were natural sources,traffic activities and atmospheric transport,geothermal and mining.Cobalt,Cr,Cu,Hg,Mn,Ni,V,Zn,Al and Fe mainly originated from natural sources,while Ba,Mo,and Pb mainly associated with traffic activities and atmospheric transport;Arsenic was almost entirely derived from geothermal and mining;sources of Cd and Sb were relatively extensive,all three potential sources contributed to Cd and Sb to some extent.High contents of Cd and Hg in soil might have been affected by traffic activities,and long-range transportation via the atmospheric dispersion of dusts from industrial activities.
关 键 词:西藏 重金属 来源 生态风险 PCA-APCS-MLR受体模型
分 类 号:X53[环境科学与工程—环境工程]
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