基于年轮年代学重建青藏高原东缘百年来重金属污染历史

采用年轮化学分析方法,测定了青藏高原东缘贡嘎山东坡峨眉冷杉(Abiesfabri)年轮中8种重金属元素(Pb、Cd、Cr、Mn、Cu、Zn、Sr和As)含量,分析了过去150年间重金属元素含量的变化特征,并探讨了重金属元素的可能来源.结果表明:Mn、Cu、Zn作为植物生长发育的必需元素,其含量显著大于其余5种重金属,8种重金属元素中,除Mn、Cu含量变化趋势较为单一之外,其余6种重金属含量均表现出复杂的变化趋势;相关分析和聚类分析显示,树轮中Cr、Sr、Pb、As为一类,主要受到人为源和自然源的综合影响;Mn、Zn、Cd为一类,主要受到人为污染源的影响;Cu元素单独归类,很大程度上来自于地壳源.青藏高原东缘地区树轮中重金属含量相对较低,但是随着工业生产活动增加,该地区重金属污染状况已有所增加,通过对该地区树轮中重金属含量的分析,有利于重建该地区重金属污染历史.

Reconstruction of Heavy Metal Deposition History in the Eastern Margin of Qinghai-Tibet Plateau Based on Ring Chronology

By using dendrochemistry method of tree rings, the variation characteristics of eight heavy metals (Pb, Cd, Cr, Mn, Cu, Zn, Sr and As) in the tree rings of Abies fabri in the eastern margin of the Qinghai-Tibet Plateau during the past 150 years were discussed, and the possible sources of heavy metal were also discussed. The results showed that Mn, Cu and Zn, as the essential elements for plant growth and development, their contents were significantly higher than the other five heavy metals. Among the eight heavy metals, except Mn and Cu, the content of the other six heavy metals showed a complex change trend. The correlation analysis and cluster analysis show that Cr, Sr, Pb, and As in the tree ring are one type, which are mainly affected by the combined effects of human and natural sources; Mn, Zn and Cd belong to the same category and are mainly affected by man-made pollution sources; Cu elements are classified separately and largely derived from crustal sources. The heavy metal content in tree rings in the eastern margin of the Qinghai-Tibet Plateau is relatively low, but with the increase of industrial production activities, the heavy metal content has increased. Through the analysis of the heavy metal content in tree rings in this area, it is helpful to reconstruct the history of heavy metal pollution in this region.