【摘要】 重金属污染的长期存在,使环境中的微生物保持并不断强化其自身重金属抗性.为了研究长期污染场地重金属污染水平和土壤中微生物重金属抗性之间的关系,本文以山西省灵丘县刁泉铜矿尾矿库区及其周边为研究对象,研究了不同立地条件下土壤重金属含量特征以及重金属抗性基因的丰度与分布,采用Hakanson潜在生态风险指数法对该区域的生态环境风险进行了评估,并对重金属及重金属抗性基因进行相关分析.结果表明:①研究区土壤重金属污染严重,7种重金属Cr、Ni、Zn、As、Cd、Cu、Pb含量均超过山西土壤背景值,单因子潜在生态危害程度顺序基本上为Cd>Pb>Cu>As>Ni>Zn>Cr.②尾矿库区存在不同程度的生态危害,尾矿坝、草地属于很强生态危害,林地、农田处于强生态危害,不同样地间的潜在生态风险顺序为草地>尾矿坝>农田>林地.③相对丰度较高的重金属抗性基因主要是针对Cu、As的抗性,针对Cu抗性以cop基因为主,针对As抗性以ars基因为主.④除copA基因与重金属之间存在显著相关性外,其他重金属抗性基因与重金属含量之间的相关性不显著.更多还原

【Abstract】 Heavy metal tolerance in environmental microbes can be gradually reinforced under the long term exposure of heavy metals. In order to detect the association between metal-resistance of soil microbe and the level of heavy metal contamination in the long term exposure at Diaoquan Copper tailing dam area in the North of Shanxi Province, study was carried out to investigate the characteristics of heavy metal contents and related abundances and distributions of the metal-resistance genes, evaluate ecological environment risk based on Hakanson method, and analyze the correlations of the metal-resistance genes. The results show that: ①The contents of Cr, Ni, Zn, As, Cd, Cu and Pb all exceed the soil background values recorded in Shanxi province, and the ecological hazard risk of single factor index was in the following order: Cd>Pb> Cu>As>Ni>Zn>Cr; ②The ecological risk levels in the soils with different land use appeared also distinct: tailing dam and grassland were at the very strong ecological risks, and woodland and farmland were at also strong ones, of which the risk levels were as the following order: grassland > tailing dam > farmland > woodland; ③The resistant genes cop to Cu and the resistant genes ars to As were respectively detected to have the significantly higher abundances in this area; ④The significant correlations were only found between copA genes and all the detected heavy metals, however, no any significantly correlations between other metal resistant genes and metals were found in this study.更多还原