摘要
风化条件作用下,黑色页岩富含的重金属元素释放到周围环境中,会造成土壤重金属的超标富集,从而形成重金属地质高背景区。为了了解黑色页岩地质高背景区重金属风化富集过程和特征,本研究以浙西地区典型寒武系黑色页岩区土壤为研究对象,运用PROFILE模型定量计算土壤剖面化学风化速率,并以此评估重金属释放速率,同时对该地区的土壤重金属潜在生态效应进行了评估。研究结果表明,土壤的化学风化速率为62.95~412.62 mmol/(m^(2)·a),盐基阳离子(Ca^(2+)、Mg^(2+)、Na^(+)和K^(+))的释放速率为97.47~806.16 mmol/(m^(2)·a)。黑色页岩土壤中碳酸盐含量的大小对风化速率强弱的影响比较大。研究区土壤As、Cd、Cr、Cu、Hg、Pb、Zn的平均释放速率分别为31.25、18.79、135.65、65.14、0.15、28.02和367.35 mmol/(m^(2)·a)。土壤的重金属浓度和盐基阳离子浓度(CBCt)对重金属释放速率的影响较大,盐基阳离子释放速率(RBC)对重金属释放速率的影响较小。研究区重金属综合潜在生态风险指数平均值为961.89,Cd的潜在生态风险指数最高,贡献率在53.44%~99.70%之间。
The heavy metal elements rich in black shale are released into the environment due to weathering,resulting in the enrichment of heavy metals in the soil,forming a high geological background area of heavy metals.In order to understand the weathering and enrichment process and characteristics of heavy metals in the high geological background area of black shale,this study used PROFILE model to quantitatively calculate the chemical weathering rate of soil profile for the typical Cambrian black shale samples in western Zhejiang,and to evaluate the release rate of heavy metals.At the same time,the potential ecological effects of soil heavy metals in this area were evaluated.The results showed that the chemical weathering rate of soil ranged from 62.95 to 412.62 mmol/(m^(2)·a),and the release rate of base cations(Ca^(2+),Mg^(2+),Na^(+)and K^(+))ranged from 97.47 to 806.16 mmol/(m^(2)·a).The content of carbonate in black shale soil has a great influence on the weathering rate.The average release rates of As,Cd,Cr,Cu,Hg,Pb and Zn in the soil of the study area are 31.25,18.79,135.65,65.14,0.15,28.02 and 367.35 mmol/(m^(2)·a)respectively.The heavy metal concentration and base cations concentration(C_(BCt))had a significant impact on the release rates of heavy metals in soil,while the release rate of base cations(R_(BC))had a relatively small impact on the release rates of heavy metals.The average value of the comprehensive potential ecological risk index of heavy metals in the study area is 961.89,and the potential ecological risk index of Cd is the highest,with a contribution rate of 53.44%-99.70%.
作者
梁孔秋
赵万伏
刘文浦
钟军伟
陈忠
常河
宋垠先
季峻峰
LIANG Kongqiu;ZHAO Wanfu;LIU Wenpu;ZHONG Junwei;CHEN Zhong;CHANG He;SONG Yinxian;JI Junfeng(Department of Geosciences,Faculty of Land Resource Engineering,Kunming University of Science and Technology;Key Laboratory of Surficial Geochemistry,Ministry of Education,School of Earth Sciences and Engineering,Nanjing University;Ningxia Institute of Land Resources Survey and Monitor)
出处
《地球与环境》
CAS
CSCD
北大核心
2024年第2期199-212,共14页
Earth and Environment
基金
宁夏回族自治区重点研发计划项目(2022BEG03054)
中国地质调查局地质调查项目(12120115048301)
国家重点研发计划专项(2017YFD0800303)
安徽省自然资源科技项目(2020-K-7)。
关键词
黑色页岩
风化速率
重金属
生态效应
black shale
weathering rate
heavy metals
ecological effect
