运用油松年轮提示承德市硫及重金属污染的历史

本文利用油松年轮研究了承德市自1800年以来大气污染的历史过程，结果表明：避暑山庄油松年轮内S含量自本世纪初开始升高，比19世纪初增加1—2倍，至70—80年代达3—5倍，而在最近8—10年则达到10倍以上。 其中碧峰门古松木质部年轮内S含量由40—50μg·g-1达到目前的572.9μg·g-1，从而指示出承德市大气SO2浓度由城市化初期的<0.1 mg·m-3增加到目前的30mg·m-3，这一历史过程主要与城市化过程尤其是近50年来工业化的出现并加剧有密切的关系。随着1927—1945年大庙铁矿的开采，年轮内Fe明显增高。Mn在整个历史时期表现为增加趋势，由1840—1850年的4.1μg·g-1增加到1980—1990年的10.4μg·g-1。Pb在1980年前的含量增加不明显，但在最近10年内形成的木质部中，Pb含量明显增加，超过1920—1930年的560%。Cu、Zn、Ni含量的变化不表现线性增加，除个别点的某些时期变化较大外，基本上很平缓。19世纪初油松年轮内S及重金属含量最低，可视为油松内元素自然背景值，与该值比较，1980—1990年这10年内年轮S含量增加了10倍，Fe，2.4倍；Pb，1.8倍；Mn，1.5倍；Ni，1.0倍；Zn，0.8倍。 日益加剧的大气污染尤其是SO2的污染，造成承德市大气质量严重下降，同时危及古松的生存，造成古松大量死亡，必须引起高度重视。

The Application of Pinus tabulaeformis Tree Rings in Revealing the Pollution History of Chengde City

The historical, air pollution of S and heavy metals since 1800 in the Chengde city was studied by analyzing the concentrations of S and heavy metals in the growth rings of Pinus tabulaeformis Carr. in the Summer Villa estate. The results showed that the S concentrations in the tree rings have elevated since the beginning of the 1900s (1900—1920). The S concentrations in the tree rings of 1810--1820, 1970—1980, and 1980—1990 have increased 1—2, 3—5 , and 10 times, respectively, of those in the tree rings of 1810--1920. At Bifengmen site, S increased significantly, from 40—50 μg· g-1 to 572.9μg·g-1. Such elevation indicated that the concentration of aerial SO2 of the City has increased from the very beginning of the urbanization. It is estimated that the aerial S concentration has increased from the pre-industrial background of less than 0.1 mg·m-3 up to the present>30 mg·m-3. This is ascribed to the result of urbanization especially the appearance and aggravation of industrialization in the city of Chengde since the 1950s. Fe appeared to have increased since 1927—1945, possibly due to the opening of Damiao Iron Mine by the Japanese; Mn increased throughout the whole history, from 4.1 μg·g-1(1840—1850)to 10.4μg·g-1 (1980—1990); Pb did not increase until 1980 but sharply elevated during the last 10 years; by 560%. It appears that the concentrations of Cu, Zn, and Ni have changed little. The concentrations of S and heavy metals in the tree rings at the beginning of 1800 were the lowest, and could be regarded as the background concentrations. It is calculated that S, Fe, Pb, Mn, Ni, Zn in the tree rings have increased 10, 2.4, 1.8, 1.5, 1.0 and 0.8 times, respectively, during the past 110 years or so. The svere air pollution, especially SO2, has resulted in air quality degradation, and also led to diebacks of the ancient pine trees in the Summer Villa estate.