地衣对重金属的累积效应用于乌鲁木齐市大气监测的研究

目的]评价地衣重金属富集能力及其在城市空气环境质量评价中的应用前景.方法]利用地衣移植法把丽石黄衣移植到乌鲁木齐市区15个监测点,用原子吸收光谱仪测量地衣体内6种重金属含量,根据重金属含量计算单项污染量指数和Nemerow综合污染指数.结果]随着移植时间的延长地衣体内的重金属含量出现上升趋势,丽石黄衣体内重金属含量具有显著的时空变化特征.同时把单向污染量指数作为变量进行聚类分析和主成分分析,显示15个监测点分为轻污染区、中度污染区、重污染区,严重污染区等三个等级.结论]地衣具有较高的重金属富集能力,对大气污染较敏感,可以作为大气环境质量评价指示地衣种类.

Study on the Application of the Heavy Metal Accumulation Effect of Lichens to the Air Quality Assessment of Urumqi City

Objective]This paper presents the results of a bioaccumulation study of heavy metals in Urumqi City based on the use of the lichen Xanthoria elegans(Link)Th.Fr and assesses its application prospects on the air quality assessment.Method]The lichens species Xanthoria elegans(Link)Th.Fr were collected from unpolluted area of Xiaoquzi forest farm located in southern mountainous area of Urumqi and transplanted to 15 different sites in Urumqi City.After transplanting every three month we collected lichens sample from different sites and the level of six heavy metals in lichens were determined by atomic absorption spectrometry. Result]The results showed that the average contents of investigated heavy metals in lichen samples were obviously increased with the exposure time increased.The changes of heavy metals content in lichens have spatial and temporal differences characteristics.At the same time,the cluster analysis method was used to the assessment of the air quality of 15 different sites.As the result showed that these lichens transplanting sites were divided into lightly polluted zone,moderately polluted zone,heavily polluted zone and gross pollution zone. Conclusion]The present study provided evidence that the lichen Xanthoria elegans(Link)Th.Fr had perfect bioaccumulation capacity to heavy metals;it was sensitive to air pollution and was suitable to be applied as bio - indicator of air pollution.