大兴安岭摩天岭雨养泥炭沼泽多环芳烃分布特征与来源分析

Distribution and Sources of Polycyclic Aromatic Hydrocarbon in Motianling Ombrotrophic Bog in Greater Hinggan Mountains

运用气相色谱-质谱（GC-MS）技术对大兴安岭摩天岭（47°22′23″ N,120°38′45″ E）雨养泥炭沼泽泥炭柱中的多环芳烃（PAHs）污染物进行了分析.结果表明,研究区雨养泥炭沼泽表层PAHs总含量的质量比为1 874.4 ng/g,与国内外雨养泥炭沼泽表层相比,其污染水平相对较高.由于研究区气候冷湿,雨养泥炭沼泽中的有机质腐殖化程度较低,有机碳含量较高,这和其PAHs含量的相关性较小.研究区样品中检测出的PAHs主要以2～3环的多环芳烃为主;由PAHs分子标志物指标分析结果可知,研究区雨养泥炭沼泽PAHs污染物的主要来源是当地森林火灾与大气远距离沉降;沉降的PAHs污染物是原油开采、石油生产和化石燃料燃烧的共同贡献.在距地表15～34 cm处,柱状剖面层的PAHs含量显著增加,这是由于1987年和1998年大兴安岭发生森林火灾树木燃烧所致.

The naturally ecological systems are imperil by the polycyclic aromatic hydrocarbon PAHs in greater areas. The researches about PAHs contaminations mostly focus on the cities, the sea, the lakes, the harbers and the mangroves, but the reports about PAHs in＇wetlands are relatively fewer. Wetland ecosystem is of frangibility, so the influence produced by PAHs is very evident. This paper was primarily to account for the distribution char- acteristic and sources of the PAHs in an ombrotrophic bog peat core from Greater Hinggan Mountains and provid- ed the evidence about the interference to the wetland by natural fires or human activities. Greater Hinggan Mountains located in the north of China, belongs to the cool temperate zone. It is an im- portant district of the ombrotrophic bogs in China. Study area is relatively far away from the industrial and the residential areas. PAHs samples from the ombrotrophic bog Motianling in Greater Hinggan Mountains （47° 22＂ 23＇N, 120°38＇45＂E）were analylized by GCMS. the results showed the concentration of PAHs in surface is 1 874.4 ng/g, and the level of PAHs in the study area is relatively high in comparison with other areas. The ratio of the TOC in the peat core is high because of the low degree of decomposition of the organic matter as it is cooler and wetter. The concentration of the PAHs is lower comparatively, and the correlation between the TOC and the RAHs is not distinct. The 2 -3rings compounds are the dorminant PAHs in the region. And the compounds of carcinogenic and metamorphic such as benzopyrene, are all below the level of horision. The mainly source of the PAHs in surface is local forest fires and the long distance sedimentation by the general air circle which is the combined contributions of the petroleum and the fuel fossil, anaylized by the PAHs molecular biomarker indexes. The concentration of the PAHs from depth of 15 cm to 34 cm rise drastically as the result of the forest fire com- bustion took place in Greater Hinggan Mountains in 1987 and 1998. The PAHs occurrence in the bottom layers are probably from natural fires or anthropogenic sources.