济宁市近地表大气降尘地球化学特征及污染来源解析

Geochemical characteristics and pollution sources identification of the near-surface atmosphere dust-fall in Jining City

在济宁城区采集近地表大气降尘及不同污染端元样品,系统分析了大气降尘和污染端元元素含量特征,并对降尘空间分布及污染来源进行研究.结果表明:燃煤、汽车尾气、交通、建筑等不同污染端元中元素含量差别明显,燃煤尘中As、Cd、Cu、F、Pb、S、Se等元素含量高于其他端元尘,且明显高于降尘,对环境影响最大,而建筑尘对环境影响相对较小.济宁市近地表大气尘中Cd、Pb、Se、Zn、Hg、CaO受到不同程度人为活动影响,相关分析和因子分析结果表明,Cd、Pb、Se、Zn主要来源于企业燃煤,贡献率26.32%,这些元素高含量区与燃煤污染源空间分布相吻合;CaO与交通扬尘产生的二次污染有关,贡献率10.06%,Hg主要源于汽车尾气排放,贡献率8.12%;而降尘中As、Cr、F、Ni基本没有受到人类活动影响,主要来源于土壤粉尘的沉降(自然源),贡献率30%,这4种污染源是济宁市大气降尘的主要来源.自然来源的As、Cr、F、Ni具有较小的富集系数,且相关性较好;而受人类活动影响的Cd、Pb、Se、Hg等元素具有较大富集系数或变异系数,在空间分布上与污染源较为一致.

Samples of near-surface atmosphere dust-fall and different pollution end-members were collected in the urban area of Jining City. The element characteristics of the near-surface atmosphere dust-fall and pollution end-members were analyzed systematically and the spatial distribution of the dust-fall and its pollution sources were studied. The results showed that the contents of elements varied obviously in different pollution end-members. The contents of As, Cd, Cu, F, Pb, S and Se within coal dust-fall were the highest, higher than those in atmosphere dust-fall and exerted great influence on the environment. The contents of Cd, Pb, Se, Zn, Hg and CaO within near-surface atmosphere dust-fall were affected by human activities in different degrees. Results of correlation analysis and factor analysis showed that Cd, Pb, Se and Zn mainly came from enterprise coal consumption, with a contribution ratio of 26.32%. The contents of the above four elements near chemical factories, steel factories and high populated regions were generally high, which was consistent with the spatial distribution of the coal pollution sources. CaO was related to traffic pollution, with a contribution ratio of 10.06%. Hg was mainly due to automobile emissions, with a contribution ratio of 8.12%. The contents of As, Cr, F and Ni within dust-fall were seldom influenced by human activities and mainly came from soil sedimentation （natural sources）, with a contribution ratio of 30%. The above four pollution sources （enterprise coal consumption, traffic pollution, automobile emissions and soil sedimentation） were the main sources of atmosphere dust-fall in Jining city. The enrichment coefficients of As, Cr, F and Ni were smaller and the spatial correlations of the four elements were better;while the enrichment coefficients and variable coefficients of elements influenced by human activities, such as Cd, Pb, Se and Hg were larger, and the spatial distributions of these elements were consistent with those of the pollution sources.