湖南某铀尾矿库周边土壤外源铀输入机制的研究
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摘要
选择湖南某铀尾矿库周边的3条土壤剖面S1、S2、S3作为研究对象,通过与区域上背景剖面以及尾矿库中铀尾砂样品的地球化学特征对比,并结合逐级化学提取技术,讨论了土壤中外源铀的输入机制。研究表明:(1)铀尾矿库对周边土壤已产生了铀污染,其中,近源土壤剖面S1、S2遭受了重度铀污染,以单因子指数法表征的污染指数Pi分别为18.98和14.76,随着远离污染源,土壤的铀污染程度呈降低趋势(如远源的剖面S3的Pi=1.35)。(2)作为农业土壤,由于受耕作过程中的人为扰动,外源铀的输入已贯穿了整个剖面。(3)土壤中外源铀的输入,特别是对于遭受了重度铀污染的近源土壤剖面,主要包括两种机制,一是随铀尾砂的机械混入,二是随渗滤液的离子输入,以前者为主。然而,对于土壤中占绝对优势的专性吸附态(Ⅱ)外源铀,主要来自于后者的贡献。随铀尾砂机械混入的铀,其赋存形态在土壤中得到了继承;随渗滤液的离子输入的铀,主要专性吸附在土壤基质上。本研究为有效开展铀尾矿库的治理提供了重要参考依据。
In this paper we took three soil profiles( i.e.,S1,S2 and S3),around a uranium mill tailings pond in Hunan Province,China as the research objective,and discussed input mechanisms of exotic uranium in the soils by contrasting their geochemical characteristics with those of the background profiles and uranium mill tailings sands in the study area by using sequential chemical extraction technique. Results show as follows.( 1) The uranium mill tailings pond has given rise to the uranium contamination to ambient soils,and the uranium contamination degree in the soils displays a decreasing trend with increasing distance from the contamination source. For example,the profiles S1 and S2 near the source received heavy uranium contamination and their uranium pollution index( Pi) characterized by the single factor index method are 18. 98 and 14. 76,respectively,and the profile S3 far away from the source is subjected to slight uranium contamination( i.e.,Pi = 1. 35).( 2) As the agricultural soils,the input of exotic uranium into them has been through the whole profiles due to the anthropogenic disturbance in the process of cultivation.( 3) The input of exotic uranium of soils,especially for that in the heavily uranium-polluted soils near the source,mainly includes two mechanisms,namely,the one is physical interfusion of uranium carried by tailings sands,and the other is the entrance of water-soluble uranium ion carried by seepage fluid from the pond,and the former is the dominant. However,for the exotic uranium of specific adsorption state,which possessed absolute superiority in the amount among various speciations of exotic uranium in the soils,it is mainly contributed from the latter. For uranium carried by tailings sands,its speciations are inherited in the soils,and for uranium carried by seepage fluid,it is mainly specifically adsorbed onto the soil matrices. This study provides a useful scientific reference for effective governance of the uranium mill tailings pond.
In this paper we took three soil profiles( i.e.,S1,S2 and S3),around a uranium mill tailings pond in Hunan Province,China as the research objective,and discussed input mechanisms of exotic uranium in the soils by contrasting their geochemical characteristics with those of the background profiles and uranium mill tailings sands in the study area by using sequential chemical extraction technique. Results show as follows.( 1) The uranium mill tailings pond has given rise to the uranium contamination to ambient soils,and the uranium contamination degree in the soils displays a decreasing trend with increasing distance from the contamination source. For example,the profiles S1 and S2 near the source received heavy uranium contamination and their uranium pollution index( Pi) characterized by the single factor index method are 18. 98 and 14. 76,respectively,and the profile S3 far away from the source is subjected to slight uranium contamination( i.e.,Pi = 1. 35).( 2) As the agricultural soils,the input of exotic uranium into them has been through the whole profiles due to the anthropogenic disturbance in the process of cultivation.( 3) The input of exotic uranium of soils,especially for that in the heavily uranium-polluted soils near the source,mainly includes two mechanisms,namely,the one is physical interfusion of uranium carried by tailings sands,and the other is the entrance of water-soluble uranium ion carried by seepage fluid from the pond,and the former is the dominant. However,for the exotic uranium of specific adsorption state,which possessed absolute superiority in the amount among various speciations of exotic uranium in the soils,it is mainly contributed from the latter. For uranium carried by tailings sands,its speciations are inherited in the soils,and for uranium carried by seepage fluid,it is mainly specifically adsorbed onto the soil matrices. This study provides a useful scientific reference for effective governance of the uranium mill tailings pond.
引文
[1]潘英杰.我国铀矿冶设施退役环境治理现状及应采取的对策[J].铀矿冶,1997,16(4):227-236.
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[11]向龙,刘平辉,张淑梅.华东某铀矿区地表水中放射性核素铀含量特征分析[J].地球与环境,2016,44(4):455-461.
[12]郝希超,陈晓明,罗学刚,等.不同牧草在铀胁迫下生长及铀富集的比较研究[J].核农学报,2016,30(3):0548-0555.
[13]刘平辉,魏长帅,张淑梅,等.华东某铀矿区水稻土放射性核素铀污染评价[J].土壤通报,2014,45(6):1517-1521.
[14]杨巍,杨亚新,曹龙生,等.某铀尾矿库中放射性核素对环境的影响[J].华东理工大学学报(自然科学版),2011,34(2):155-159.
[15]王丽超,罗学刚,彭芳芳,等.铀尾矿污染土壤微生物活性及群落功能多样性变化[J].环境科学与技术,2014,37(3):25-31.
[16]连国玺,刘晓超,王春普,等.辐射防护最优化在铀矿冶污染农田治理控制水平确定中的应用[J].铀矿冶,2013,32(3):161-164.
[17]杜洋,朱晓杰,高柏,等.铀矿山尾矿库区典型场地中铀的分布特征[J].有色金属(矿山部分),2014,66(1):5-9.
[18]张学礼,徐乐昌,张辉.某铀尾矿库周围农田土壤重金属污染与评价[J].环境科学与技术,2015,38(6):221-226.
[19]马腾,王焰新.U(Ⅵ)在浅层地下水系统中迁移的反应-输运耦合模拟——以我国南方核工业某尾矿库为例[J].地球科学——中国地质大学学报,2000,25(5):456-461.
[20]李先杰,蔡振民,何文星,等.铀尾矿库滩面含水量分布与氡析出率预测[J].铀矿冶,2005,24(3):145-148.
[21]Nesbitt H W,Young G M.Early Proterozoic climates and plate motions inferred from major element chemistry of lutite[J].Nature,1982,299:715-717.
[22]Mc Lennan S M.Weathering and global denudation[J].Journal of Geology,1993,101:295-303.
[23]Fralick P W,Kronberg B I.Geochemical discrimination of clastic sedimentary rock sources[J].Sedimentary Geology,1997,113:111-124.
[24]Sheldon N D,Tabor N J.Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols[J].Earth-Science Reviews,2009,95(1/2):1-52.
[25]中国环境监测总站.中国土壤元素背景值[M].北京:中国环境科学出版社,1990:454.
[26]刘平辉,魏长帅,张淑梅,等.华东某铀矿区水稻土放射性核素铀污染评价[J].土壤通报,2014,45(6):1517-1521.
[27]沈体忠,朱明祥,肖杰.天门市土壤-水稻系统重金属迁移积累特征及其健康风险评估[J].土壤通报,2014,45(1):221-226.
[28]Martínez-Aguirre A,Garcia-León M,Ivanovich M.U and Th speciation in river sediments[J].Science of the Total Environment,1995,173/174:203-209.
[29]Guo P,Duan T,Song X,et al.Evaluation of a sequential extraction for the speciation of thorium in soils from Baotou area,Inner Mongolia[J].Talanta,2007,71:778-783.
[30]Crespo M T,Villar L P D,Jiménez A,et al.Uranium isotopic distribution in the mineral phases of granitic fracture fillings by a sequential extraction procedure[J].Applied Radiation and Isotopes,1996,47:927-931.
[31]Feng Z G,Zhang B,Duan X Z,et al.Uranium mobility in waste materials generated by uranium mining and hydrometallurgy:Implications for its in-situ immobilization[J].Journal of Residuals Science&Technology,2015,12(Supp.1):S159-S163.
[32]黄镇国,张伟强,陈俊鸿,等.中国南方红色风化壳[M].北京:海洋出版社,1996:1-177.
[33]Trudgill S.Limestone Geomorphology[M].London:Longman Group Limited,1985:26-52.
[34]Egli M,Fitze P.Quantitative aspects of carbonate leaching of soils with differing ages and climates[J].Catena,2001,46:35-62.
[35]邹献中,张超兰,宁建凤,等.不同浓度铜离子土壤的吸附-解吸行为——兼论弱专性吸附态的存在[J].土壤学报,2012,49(5):892-900.
[36]Campbell K M,Gallegos T J,Landa E R.Biogeochemical aspects of uranium mineralization,mining,milling,and remediation[J].Applied Geochemistry,2015,57:206-235.
[2]潘英杰,李玉成,薛建新,等.我国铀矿冶设施退役治理现状及对策[J].辐射防护,2009,29(3):167-171,198.
[3]张学礼,徐乐昌,魏广芝,等.铀矿冶放射性固体废物最小化[J].铀矿冶,2010,29(4):204-209.
[4]Abdelouas A.Uranium mill tailings:Geochemistry,mineralogy and environmental impact[J].Elements,2006,2(6):335-341.
[5]Nriagu J,Nam D-H,Ayanwola T A,et al.High levels of uranium in groundwater of Ulaanbaatar,Mongolia[J].Science of the Total Environment,2012,414:722-726.
[6]Banning A,Rüde T R.Apatite weathering as a geological driver of high uranium concentrations in groundwater[J].Applied Geochemistry,2015,59:139-146.
[7]Carvalho I G,Cidu R,Fanfani L,et al.Environmental impact of uranium mining and ore processing in the Lagoa Real District,Bahia,Brazil[J].Environmental Science&Technology,2005,39:8646-8652.
[8]Gavrilescu M,Pavel L V,Cretescu I.Characterization and remediation of soils contaminated with uranium[J].Journal of Hazardous Materials,2009,163,475-510.
[9]Campbell K M,Gallegos T J,Landa E R.Biogeochemical aspects of uranium mineralization,mining,milling,and remediation[J].Applied Geochemistry,2015,57:206-235.
[10]Robertson J,Hendry M J,Essilfie-Dughan J,et al.Precipitation of aluminum and magnesium secondary minerals from uranium mill raffinate(p H1.0-10.5)and their controls on aqueous contaminants[J].Applied Geochemistry,2016,64:30-42.
[11]向龙,刘平辉,张淑梅.华东某铀矿区地表水中放射性核素铀含量特征分析[J].地球与环境,2016,44(4):455-461.
[12]郝希超,陈晓明,罗学刚,等.不同牧草在铀胁迫下生长及铀富集的比较研究[J].核农学报,2016,30(3):0548-0555.
[13]刘平辉,魏长帅,张淑梅,等.华东某铀矿区水稻土放射性核素铀污染评价[J].土壤通报,2014,45(6):1517-1521.
[14]杨巍,杨亚新,曹龙生,等.某铀尾矿库中放射性核素对环境的影响[J].华东理工大学学报(自然科学版),2011,34(2):155-159.
[15]王丽超,罗学刚,彭芳芳,等.铀尾矿污染土壤微生物活性及群落功能多样性变化[J].环境科学与技术,2014,37(3):25-31.
[16]连国玺,刘晓超,王春普,等.辐射防护最优化在铀矿冶污染农田治理控制水平确定中的应用[J].铀矿冶,2013,32(3):161-164.
[17]杜洋,朱晓杰,高柏,等.铀矿山尾矿库区典型场地中铀的分布特征[J].有色金属(矿山部分),2014,66(1):5-9.
[18]张学礼,徐乐昌,张辉.某铀尾矿库周围农田土壤重金属污染与评价[J].环境科学与技术,2015,38(6):221-226.
[19]马腾,王焰新.U(Ⅵ)在浅层地下水系统中迁移的反应-输运耦合模拟——以我国南方核工业某尾矿库为例[J].地球科学——中国地质大学学报,2000,25(5):456-461.
[20]李先杰,蔡振民,何文星,等.铀尾矿库滩面含水量分布与氡析出率预测[J].铀矿冶,2005,24(3):145-148.
[21]Nesbitt H W,Young G M.Early Proterozoic climates and plate motions inferred from major element chemistry of lutite[J].Nature,1982,299:715-717.
[22]Mc Lennan S M.Weathering and global denudation[J].Journal of Geology,1993,101:295-303.
[23]Fralick P W,Kronberg B I.Geochemical discrimination of clastic sedimentary rock sources[J].Sedimentary Geology,1997,113:111-124.
[24]Sheldon N D,Tabor N J.Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols[J].Earth-Science Reviews,2009,95(1/2):1-52.
[25]中国环境监测总站.中国土壤元素背景值[M].北京:中国环境科学出版社,1990:454.
[26]刘平辉,魏长帅,张淑梅,等.华东某铀矿区水稻土放射性核素铀污染评价[J].土壤通报,2014,45(6):1517-1521.
[27]沈体忠,朱明祥,肖杰.天门市土壤-水稻系统重金属迁移积累特征及其健康风险评估[J].土壤通报,2014,45(1):221-226.
[28]Martínez-Aguirre A,Garcia-León M,Ivanovich M.U and Th speciation in river sediments[J].Science of the Total Environment,1995,173/174:203-209.
[29]Guo P,Duan T,Song X,et al.Evaluation of a sequential extraction for the speciation of thorium in soils from Baotou area,Inner Mongolia[J].Talanta,2007,71:778-783.
[30]Crespo M T,Villar L P D,Jiménez A,et al.Uranium isotopic distribution in the mineral phases of granitic fracture fillings by a sequential extraction procedure[J].Applied Radiation and Isotopes,1996,47:927-931.
[31]Feng Z G,Zhang B,Duan X Z,et al.Uranium mobility in waste materials generated by uranium mining and hydrometallurgy:Implications for its in-situ immobilization[J].Journal of Residuals Science&Technology,2015,12(Supp.1):S159-S163.
[32]黄镇国,张伟强,陈俊鸿,等.中国南方红色风化壳[M].北京:海洋出版社,1996:1-177.
[33]Trudgill S.Limestone Geomorphology[M].London:Longman Group Limited,1985:26-52.
[34]Egli M,Fitze P.Quantitative aspects of carbonate leaching of soils with differing ages and climates[J].Catena,2001,46:35-62.
[35]邹献中,张超兰,宁建凤,等.不同浓度铜离子土壤的吸附-解吸行为——兼论弱专性吸附态的存在[J].土壤学报,2012,49(5):892-900.
[36]Campbell K M,Gallegos T J,Landa E R.Biogeochemical aspects of uranium mineralization,mining,milling,and remediation[J].Applied Geochemistry,2015,57:206-235.