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《Chemie der Erde / Geochemistry》2016,76(4):501-518
The old Senhora das Fontes uranium mine, located in central Portugal, was closed down in 1971. The treatment of ores from this mine and other mines by heap-leach ended in 1982. Seven dumps partially covered by vegetation were left in the area. Soil and stream sediment samples were collected in December 2009. The remediation was carried out from May 2010 to January 2011. Stream sediment samples were collected again in October 2013. Before the remediation, soils from inside the mine influence area have higher Al, As, Co, Cr, Cu, Fe, Ni, Sr, Th, U and Zn concentrations than soils from outside this area, due to radionuclides, metals and metalloid released from the mine dumps. The principal component analysis (PCA) shows a distinction between soils from inside and outside the mine influence area. The U(VI), As(V) and metals from soils can be adsorbed to Fe-oxyhydroxides and the humic acid can increase the U uptake. Soils must not be used for public or private green and residential areas, because they are contaminated in U, As, Co, Cd and Ni. Before the remediation, downstream sediments have higher Al, As, Cu, Mn, Ni, Pb, U and Zn than upstream sediments, due to erosion and percolation of water through the mine dumps. The PCA shows a distinction between downstream and upstream sediments. The U(VI), Th and As(V) can be adsorbed to Fe-oxyhydroxides. The stream sediments are contaminated in As, Mn, Th and U. Downstream sediments are the most contaminated in U and As. After the remediation, upstream and downstream sediments have generally higher Al, Fe, As, Cr, Ni, Th, U and Zn concentrations than before the remediation, attributed to the relocation of dumps. Radionuclides, metals and metalloids were transported by surface water. Consequently downstream sediments have higher Al, As, Cu, Mn, Ni, Th, U and Zn concentrations than upstream sediments. The U(VI), Th and As(V) can be adsorbed to Fe-oxyhydroxides. Stream sediments became more contaminated in U, Th and As than before the remediation, but more intensively downstream. 相似文献
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2022年,中国地质学会迎来了百年华诞,为进一步扩大百年庆典活动的影响力,于2021年6月向社会公开征集活动标识。经遴选,拟启用下图作为中国地质学会百年华诞庆典活动唯一指定标识。 相似文献
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纳米材料的发展及其展望 总被引:4,自引:1,他引:3
介绍了纳米材料的研究现状及特点,对纳米组装材料,纳米结构材料、等纳米材料的研究进行了评述,并对21世纪纳米材料的发展新动向提出展望。 相似文献
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天祝-古浪5.4级地震前后波谱异常特征研究 总被引:2,自引:0,他引:2
使用CDSN兰州台数字地震记录资料,用IASPEI推荐的Seisg ram谱分析软件,对1996年6月1日发生在甘肃天祝-古浪MS 5. 4地震之前的3个前震和14个余震的波谱特征作了初步研究: ① 在主震后地震的纵横波零频位移谱值的对数比值从1. 2左右下降到1. 0左右; ② 纵横波谱的拐角频率比值和高频衰减斜率比值均由主震前的1. 0下降到主震后的0. 8;③ 各频谱特征量呈现异常的时间基本上同步,其异常形态也相似; ④ 前震的各频谱特征量较余震有明显差异,因而有可能成为预测主震的重要指标。 相似文献
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结合日常电视天气预报节目的情况,阐述动画在天气预报节目中的重要性,介绍如何用多媒体动画软件实现常见天气示意图,为天气预报节目制作人员日常动画制作提供参考。 相似文献
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《Chemie der Erde / Geochemistry》2015,75(3):345-356
The old Senhora das Fontes uranium mine, in central Portugal, consists of quartz veins which penetrated along fracture shear zones at the contact between graphite schist and orthogneiss. The mine was exploited underground until a depth of 90 m and was closed down in 1971. The ores from this mine and two others were treated in the mine area by the heap-leach process which ended in 1982. Seven dumps containing a total of about 33,800 m3 of material and partially covered by natural vegetation were left in the mine area. A remediation process took place from May 2010 to January 2011. The material deposited in dumps was relocated and covered with erosion resisting covers. Surface water and groundwater were collected in the wet season just before the remediation, in the following season at the beginning of the remediation and also after the remediation in the following dry season. Before, at the beginning and after the remediation, surface water and groundwater have an acid-to-alkaline pH, which decreased with the remediation, whereas Eh increased. In general, before the remediation, uranium concentration was up to 83 μg/L in surface water and up to 116 μg/L in groundwater, whereas at the beginning of the remediation it increases up to 183 μg/L and 272 μg/L in the former and the latter, respectively, due to the remobilization of mine dumps and pyrite and chalcopyrite exposures, responsible for the pH decrease. In general, after the remediation, the U concentration decreased significantly in surface water and groundwater at the north part of the mine area, but increased in both, particularly in the latter up to 774 μg/L in the south and southwest parts of this area, attributed to the remobilization of sulphides that caused mobilization of metals and arsenic which migrated to the groundwater flow. Uranium is adsorbed in clay minerals, but also in goethite as indicated by the geochemical modelling. After the remediation, the saturation indices of oxyhydroxides decrease as pH decreases. The remediation also caused decrease in Cd, Co, Cr, Ni, Pb, Zn, Cu, As, Sr and Mn concentrations of surface water and groundwater, particularly in the north part of the mine area, which is supported by the speciation modelling that shows the decrease of most dissolved bivalent species. However, in general, after the remediation, Th, Cd, Al, Li, Pb, Sr and As concentrations increased in groundwater and surface water at south and southwest of the mine area. Before and after the remediation, surface water and groundwater are contaminated in U, Cd, Cr, Al, Mn, Ni, Pb, Cu and As. Remediation caused only some improvement at north of the mine area, because at south and southwest part, after the remediation, the groundwater is more contaminated than before the remediation. 相似文献
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