摘要
由于青藏高原生态系统的脆弱性和对人类活动的敏感性,近年来高原环境中与人类活动相关的重金属污染研究受到越来越多的关注.本文通过2021～2022年间采集的青藏高原表土样品,结合同时期采集的周边高海拔冰川区雪冰样品,分析测定了 As、Cr、Co、Ni、Cu、Mo、Cd、Pb和Sb共9种重金属元素的含量和组成特征.结果表明,青藏高原表土中重金属的含量(均值为256.5μg/g)远高于雪冰中重金属(均值为14.6μg/L)的含量.其中As的Igeo平均值为1.32,总体处于中度污染水平,而土壤中其他重金属以无污染特征为主.表土中重金属的组成和空间分布与周边冰川区雪冰中表现出明显不同特征,而且不同区域表土重金属的空间分布、组成和富集系数(EFs)没有明显差别.结合相关性、主成分分析和APCS-MLR等方法,发现表土中重金属有3个主要来源,分别为居民生活和工业用煤有关的煤燃烧源(42.3％)、局地地表自生土壤来源(20.6％)和交通排放源(14.2％).高海拔雪冰和表土中重金属的组成、分布存在差异,可能是由于地表样品中重金属受到自然风化、和人类活动影响导致远距离输入源的贡献被掩盖,而雪冰中重金属则更多受到大气环流远距离输入污染源的影响.本研究较为全面的展示了目前青藏高原大范围区域表土中重金属组成状况,反映出部分元素的明显富集(例如As)和整体上重金属元素含量仍然表现为清洁的自然状况.
Abstract
Due to the delicate ecological balance of the Tibetan Plateau(TP)and its heightened vulnerability to human-induced impacts,there has been a growing scholarly focus on investigating heavy metal pollution in the plateau's environment in recent years.In this study,we conducted a comprehensive analysis of nine distinct heavy metal elements(HMs),including As,Cr,Co,Ni,Cu,Mo,Cd,Pb,and Sb,using topsoil samples collected from the TP during the period of 2021～2022.This analysis was complemented by evaluating snow and cryoconite samples obtained during the same timeframe.Our investigation revealed a significant disparity in HM content between TP topsoil(with an average of 256.5μg/g)and snow-cryoconite samples(with an average of 14.6μg/L).Specifically,the calculated average Igeo value for As indicated moderate pollution(1.32),while the remaining heavy metals in the soils showed predominantly non-polluted to lightly polluted levels.Clear differences in both composition and spatial distribution of HMs were evident between the topsoil and the snow-cryoconite matrix.Regarding spatial distribution,composition,and Enrichment Factors(EFs),congruence was observed among different regions in the topsoil samples.Through a triangulation of correlation analysis,principal component analysis,and the APCS-MLR method,our investigation identified three principal sources of HMs in the topsoil:coal combustion(42.3％),inherent natural sources within the surface soil(20.6％),and vehicular emissions(14.2％).Disparities in the composition and distribution of HMs within high-altitude glaciers and topsoil samples were attributed to local processes of natural weathering and anthropogenic influences on the topsoil.These factors tend to mask the influence of long-range transport(LRT)on HM content in topsoil.Conversely,HMs present in snow and cryoconite samples are more susceptible to the effects of LRT sources.This study provides a holistic overview of the composition of HMs in the extensive expanse of TP topsoil,highlighting significant enrichment of certain elements,such as As,while emphasizing an overall condition of relative purity in terms of HM content.
维普
万方数据