伊春西林铅锌矿区兴安落叶松年轮中重金属元素含量的年际变化

Interannual variation patterns of heavy metals concentrations in tree rings of Larix gmelinii near Xilin Lead-zinc Mine, Yichun of Northeast China

利用树木年轮环境学分析方法,测定了伊春西林铅锌矿附近兴安落叶松年轮中Pb、Cd、Zn、Cu、Mn5种重金属元素含量的变化.结果表明:在矿区附近的兴安落叶松年轮中,Mn含量最高,Cd含量最低.近地面处年轮中的Cd、Zn、Cu含量显著高于胸高处,而近地面和胸高处的Pb和Mn含量差异不显著.1987—2010年,除Pb含量有轻微上升外,其他4种元素含量均呈下降趋势,其中Cd含量下降趋势最明显,Zn、Cu、Mn含量均先下降后上升.随着兴安落叶松年轮宽度的增加,Pb含量下降,其他4种元素含量均增加.近地面处Pb含量与其他4种元素含量呈显著正相关,而在胸高处的相关性不显著,Cd含量甚至随Pb含量增加而显著下降.兴安落叶松年轮中重金属元素含量变化受铅锌矿产量和采矿活动的影响,可利用年轮中Pb含量重建采矿历史.目前,Pb含量已经对周围环境造成污染,如果继续开采,应加强对尾矿中重金属元素的治理.

By using dendro-environmental methods, this paper measured and analyzed the variations of five heavy metals （Pb, Cd, Zn, Cu, and Mn） concentrations in the tree rings of Larix gmelinii near Xilin Lead-zinc Mine, Yichun of Northeast China. Among the test heavy metals, the Mn concentration in the tree rings was the highest, while the Cd concentration was the lowest. The Cd, Zn, and Cu concentrations in the tree rings near the ground （0.3 m high from the ground, D0.3） were significantly higher than those at breast height （1.3 m high from the ground, D1.3）, while the Pb and Mn concentrations at the two heights had less difference. In 1987-2010, the Pb concentration in the tree rings had a slight increase, but the Cd, Zn, Cu, and Mn concentrations presented a decreasing trend. The Cd concentration decreased most obviously, while the Zn, Cu, and Mn concentrations decreased after an initial increase. With the increase of tree ring width, the Pb concentration decreased, while the Cd, Zn, Cu, and Mn concentrations were in adverse. The relationships between the Pb and other four heavy metals concentrations in the tree rings near the ground and at breast height had definite differences. Near the ground, the Pb concentration showed a significant positive correlation with the other four heavy metals concentrations, but at breast height, less correlation was observed, and even, the Cd concentration decreased significantly with increasing Pb concentration. The variations of the heavy metals concentrations in the L. gmelinii tree rings could be affected by the production and mining activities of Xilin Lead-zinc Mine, and thus, it would be possible to use the Pb concentration in the tree rings to reconstruct the mining history of the study area. At present, the Pb concentration in the tailing wastes has polluted the surrounding environments near Xilin Lead-zinc Mine. Therefore, countermeasures should be adopted to manage the heavy metals in tailing wastes if the Mine would be continued to be mined.