• 关键词：重金属污染  黑色页岩土壤  因子分析  富集因子  湖南

• 基金项目：国家自然科学基金(No.40572172);湖南省教育厅重点项目(No.07A309)

• 唐晓燕
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 彭渤
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 余昌训
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 谢淑容
• 东华理工大学地球科学与测绘工程学院, 抚州 344000

• 杨广
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 尹春燕
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 刘茜
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 杨克苏
• 湖南师范大学资源与环境科学学院, 长沙 410081

• 摘要：本研究对湖南安化县东坪、烟溪两地发育于下寒武统黑色页岩上的6个土壤剖面进行系统采样,并利用ICP-MS等分析技术对土壤和相应岩石样品的主量元素和微量元素(包括重金属和稀土元素)含量进行了分析.主量元素A-CN-K(Al₂O₃-CaO+Na₂O-K₂O)图解显示,黑色页岩土壤的形成是黑色页岩化学风化的结果,经历了早期的Ca、Na淋失和后期的Al、Fe富集过程后,土壤具有贫Ca、Na而富Al、Fe的化学组成特征.多因子分析和相关性分析结果表明,成土过程中,微量元素可分为稳定元素(Ti、Zr、Nb、Hf、Ta、W等)、次稳定元素(Be、Sc、Ga、Ge、Rb、Cs、Pb、Th、Ba等)、活动性较强的元素(REE、Y、P、Sn等)和强活动性元素(Mn、Co、Ni、Zn、Cd、Tl、V、Mo、Sb、U等).富集因子重金属污染评价显示,V、U仅在烟溪土壤剖面达到显著污染程度,Sn、Ba在东坪土壤剖面达到显著污染.Mo、Cd、Sb等重金属则在东坪和烟溪土壤均达到显著污染程度,其中,Cd在东坪可达到高度污染水平,而Mo在烟溪可达到极度污染水平.微量元素及稀土元素地球化学示踪分析显示,黑色页岩土壤没有受到外来物源的干扰,土壤重金属污染为来自黑色页岩的自然污染源.

• Abstract：We conducted geochemical analysis on soils derived from the Lower-Cambrian black shales in Dongping and Yanxi areas of the Anhua County,central Hunan(China) by sampling six soil profiles.Concentrations of major and trace elements(including heavy metals and rare earth elements) of the soil samples and relative parent rocks were measured using ICP-MS.The A-CN-K plots of major elements indicates that the soils derived from the black shales were developed from black shale weathering,which underwent at least two stages of element mobility:the early stage of Na and Ca loss,and the later stage of Al and Fe enrichment.Then,the soils are characterized by depletion of elements Ca and Na,and by enrichment of elements Al and Fe.Results of factor analysis and PCC analysis of major and trace elements of the soils indicate that behaviors of trace elements during pedogenesis can be grouped into the following four groups:the immobile elements including Ti,Zr,Nb,Hf,Ta and W,whose geochemical mobility was limited during pedogenesis;the relatively stable elements including Be,Sc,Ga,Ge,Rb,Cs,Pb,Th and Ba,which were not mobile but not so stable as the former group;the mobile elements including REE,Y,P and Sn,which were significantly mobile during soil formation;and the strongly mobile elements including Mn,Co,Ni,Zn,Cd,Tl,V,Mo,Sb and U.The soils derived from black shales might be heavy-metal contaminated by reflecting the extreme chemical compositions of the parent black shales.The degree of the heavy metal contamination was evaluated using the enrichment factors(EF).The evaluation results show that soils from the Yanxi profiles might be heavily contaminated by metals V and U,and that from the Dongping profiles by metals Sn and Ba.Soils derived from the parent black shales in both Yanxi and Dongpin areas might be contaminated by metals Mo,Cd and Sb.Concentrations and distribution patterns of some trace elements(including rare earth elements) of the soils suggest that the soil compositions were not distributed and impacted by other materials from other external sources.Therefore,the heavy metal contamination in the soils of these areas was caused by metals from the parent black shales,which is a geological source for heavy metal contamination of soils.

• Key words：heavy metal contamination  black-shale soil  factor analysis  enrichment factor  Hunan Province

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