摘要
文章以拉萨河自上游热振藏布到下游雅鲁藏布江汇入口之前、拉萨河主干流及其主要支流为研究对象,针对河流表层沉积物中重金属元素的时空分布特征开展了研究。同时通过多元统计学方法对拉萨河沉积物中重金属元素进行溯源,运用潜在生态风险评价方法对表层沉积物中的主要重金属进行生态风险评价。研究结果表明:总量上,被研究流域表层沉积物重金属含量与西藏土壤背景值接近;从上游到下游,拉萨河与其支流沉积物重金属含量表现出极为相似的分布特征;从同一水平年内三个(枯、丰、平)不同水期来看,各重金属元素含量变化差异性较小,显示了不同水期重金属在沉积物中较为相似的富集规律。主成分分析和Pearson相关性分析结果表明:拉萨河表层沉积物中重金属的时空分布情况主要受两个方面的影响和控制,即:(1)流域内丰富的矿产资源及前期管理疏漏的开采活动和流域内丰富的地热资源对表层沉积物元素组成及含量的影响;(2)流域内的岩石风化和侵蚀等自然过程的控制。潜在风险评价结果表示:拉萨河流域总体呈现低生态风险水平。
Surface sediment samples were collected from the Lhasa River catchments and characteristics of the spatial and temporal distribution of heavy metals in the sediments were studied.The potential ecological risk assessment was applied for evaluating the ecological risk of the major heavy metals in the river catchments.The results showed that the content of heavy metals in the surface sediments was similar to the background value of it in the soil in Tibet.The heavy metal contents in the surface sediments of the main river and its tributaries showed very similar distribution characteristics from the upstream to the downstream.The variation of heavy metals content at three different water periods(low,plentiful and common)in the same year(2016)was also relatively small indicating a similar accumulating rule of heavy metals in sediments at different water periods.The principal component analysis and Pearson correlation analysis showed that the temporal and spatial distribution of heavy metals in surface sediments of Lhasa river was mainly controlled by two factors,i.e.,①the influence of abundant mineral resources,less controlled mining activities in the 90s of last century and the rich in geothermal resources in the basin on the elemental composition and content in surface sediments and②natural processes such as rock weathering and erosion dominated in the river catchments.Potential risk assessment showed that the overall ecological risk level introduced by heavy metals was low in the Lhasa River catchments.
作者
李政
陈虎林
余璨
李清清
黄香
LI Zheng;CHEN Hu-lin;YU Can;LI Qing-qing;HUANG Xiang(School of Sciences,Tibet University,Lhasa,850000,China)
出处
《高原科学研究》
CSCD
2019年第1期58-70,113,共14页
Plateau Science Research
基金
国家自然科学基金(21667027)
国家科技部基础性工作专项(2015FY111000)
西藏大学高水平人才培养计划项目(2016-GSP-020)
关键词
拉萨河
表层沉积物
重金属
时空分布
潜在生态风险评价
Lhasa River
surface sediment
heavy metals
spatial and temporal distribution
potential ecological risk assessment
