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1.
Barbara Palumbo-Roe Ben Klinck Vanessa Banks San Quigley 《Journal of Geochemical Exploration》2009,100(2-3):169-181
In this study we investigated the sulphidic mine tailings from Frongoch and Grogwynion, two abandoned lead zinc mines in mid-Wales, UK. Despite falling within the same ore field the mine waste characterisation has identified differences in the tailings from the two sites. Bulk concentrations range from 10 to 52 g kg− 1 for Pb, 1.1 to 2.9 g kg− 1 for Zn in Grogwynion and from 1.0 to 130 g kg− 1 for Pb, 11 to 110 g kg− 1 for Zn in Frongoch. An experimental (European standard leaching tests TS 14429 and TS 14405) and geochemical modelling approach was used to study the leaching composition as a function of pH and liquid/solid ratio. There was little correlation between the tailings bulk metal concentrations and the leachate composition, but variations in Pb and Zn concentrations were found to be consistent with control of dissolved Pb and Zn by secondary minerals and the mechanisms of dissolution/precipitation/sorption involving them. Specifically, the Grogwynion mine tailings with near-neutral pH have predominantly lead and zinc carbonates controlling Pb and Zn solubility in the leachates, whereas the Pb and Zn concentrations in Frongoch leachates are best modelled with a surface complexation model for metal sorption to oxyhydroxides. The different speciation results in a greater sensitivity of Grogwynion tailings to acidification with a potential release of Pb in solution up to 10 times higher than in Frongoch, despite similar bulk Pb concentrations. At acid pH, Zn is similarly dissolved to a greater extent in Grogwynion than in Frongoch tailings. There was no evidence of sulphide oxidation during the batch and column leaching tests and the suitability of using these European leaching standards for the characterisation of sulphidic mine waste materials for waste management purposes has been considered. 相似文献
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《Applied Geochemistry》2005,20(3):487-506
Sequential leaching methods have been used to determine the mineralogical distribution of some trace elements for environmental purposes, such as radiological contamination of soils and sediments, bioavailability studies and natural analogues of deep geological radwaste disposals. In this context, a 7-step-sequential leaching protocol is applied to Fe(III)–U(VI)-rich fracture filling materials from the oxidised zone of the “Mina Fe” U deposit to identify and evaluate the main sinks of natural nuclides and other analogue trace elements, since it is crucial in the performance assessment of a nuclear waste repository.After a careful characterisation of the samples, the analytical data from each leaching step were statistically analysed and then interpreted in light of the mineralogical and geochemical features of the samples. Precise knowledge of the mineralogical distribution of trace elements by sequential leaching methods is quite complex, mainly due to cross-contamination throughout the different steps of the experiments. Thus, the results obtained suggest that U is retained as U-minerals, mainly oxides, closely associated with crystalline Fe-oxyhydroxides. Though Ce and La also form independent compounds, such as Ce oxides and La–Nd phosphates, they are mainly retained by the amorphous Mn-oxyhydroxides. However, the crystalline Mn-oxyhydroxides are the main sink for Ni and crystalline Fe-oxyhydroxides mainly retain P. 相似文献
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Alexandra N. Golab Mark A. Peterson Buddhima Indraratna 《Environmental Earth Sciences》2009,59(1):241-254
The Shoalhaven region of NSW experiences environmental acidification due to acid sulphate soils (ASS). In order to trial an
environmental engineering solution to groundwater remediation involving a permeable reactive barrier (PRB), comprehensive
site characterisation and laboratory-based batch and column tests of reactive materials were conducted. The PRB is designed
to perform in situ remediation of the acidic groundwater (pH 3) that is generated in ASS. Twenty-five alkaline reactive materials
have been tested for suitability for the barrier, with an emphasis on waste materials, including waste concrete, limestone,
calcite-bearing zeolitic breccia, blast furnace slag and oyster shells. Following three phases of batch tests, two waste materials
(waste concrete and oyster shells) were chosen for column tests that simulate flow conditions through the barrier and using
acidic water from the field site (pH 3). Both waste materials successfully treated with the acidic water, for example, after
300 pore volumes, the oyster shells still neutralised the water (pH 7). 相似文献
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Uranium is a common contaminant of concern in the aquifers of nuclear waste management facilities around the world. The Electrochemical Plant (ECP) (Krasnoyarsk Krai, Russia) and the Angarsk Electrolysis Chemical Complex (AEСC) (Irkutsk Region, Russia) have produced enriched uranium and related nuclear wastes (sludge materials) since the 1960s. The results of the detailed sampling of groundwater and waste solutions near the storage sites of radioactive waste are presented elsewhere (Gaskova et al., 2011, Boguslavskiy et al., 2012). A number of experimental studies were conducted in the laboratory (a) to investigate the uranium-containing sludge leaching by regional groundwater and (b) to understand the ability of host sediments to retain major and minor components from drainage solutions as a function of the water/rock ratio (indicating the timescale over which the behavior is observed). The geochemical modeling code “HCh” was applied to simulate these processes and to predict the long-term environmental impact of residual uranium. The experimental and thermodynamic results indicate that U leaching from the sludge materials is less dependent on the specific solubility of the sludge sediments and more dependent on the solid uranium species in this sludge. The model simulation of uranium sorption in dynamic experiments was successful only in the case of the permanent filtration of less mineralized groundwater in fine-grained clay rocks. To more accurately describe the potential future release of U from the residual waste sites, a series of batch reactor experiments needs to be conducted. 相似文献
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Yinghong Qin Haifeng Yang Zhiheng Deng Jiaming Zhang 《Environmental Earth Sciences》2014,72(5):1533-1540
A simplified model is proposed to estimate the leaching constituents from waste granular pavement base to adjacent groundwater. The model considers pollutants leaching from a longitudinally infinite waste granular base. The leaching of the base is deemed to obey the diffusion model. After leaving the pavement layers, the leachate is subjected to retardation and dilution during its transport to the nearby aquifer. The retardation is estimated from the breakthrough curve of steady-water flow through a homogeneous soil profile. The model is available for any waste granular base that contains any type of leachable pollutants. But parameterization of the model is different substantially for different pollutants; therefore how to parameterize the mode is discussed. Recycled glass is exemplified as the granular base materials, and the transport of Cadmium to the local aquifer is demonstrated. A sensitivity study is conducted to demonstrate the influences of field conditions and waste-leaching characteristics on the pore concentration of the pollutants in the target well. 相似文献
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Being a potential preferential way for water to flow, interfaces between host rock and engineered barriers are critical in the design of deep radioactive waste repositories. In case of cementitious materials, presence of water may lead to long term degradation by leaching. Such a phenomenon could impede the integrity of the confinement by its effect on the hydro-mechanical properties of the interface. Recent experimental results from Buzzi et al. [8] have evidenced some effects of leaching on the hydro-mechanical behavior of rock–concrete interfaces for one leaching time. This paper intends to investigate the influence of leaching on the mechanical behavior of rock–mortar interfaces by means of numerical simulations. These latter will be run for several leaching times to produce a better understanding of the phenomenon. For this purpose, a DEM approach has been developed to simulate the increase of the macro-porosity resulting from the leaching process. The implementation of the approach is first discussed. Then direct shear tests under constant normal stress are performed on a simple interface geometry and on a natural interface geometry. The results after Buzzi et al. [8] are corroborated by this research. 相似文献
9.
Mahtab Ahmad Deok Hyun Moon Kyoung Jae Lim Christopher L. Shope Sang Soo Lee Adel R. A. Usman Kwon-Rae Kim Jeong-Hun Park Seung-Oh Hur Jae E. Yang Yong Sik Ok 《Environmental Earth Sciences》2012,67(4):1023-1031
Military shooting range soils contaminated by heavy metals have been subjected to remediation efforts to alleviate the detrimental effects of exposure on humans and the surrounding environment. Waste materials can be used as cost-effective soil amendments to immobilize heavy metals in contaminated soils. In this study, naturally occurring lime-based waste materials including egg shells, oyster shells, and mussel shells were assessed for their effectiveness toward heavy metal immobilization in military shooting range soil in Korea. Soil was treated in batch leaching experiments with 0, 2.5, 5, 10, and 15% of each lime-based waste material. The results showed that the lime-based waste materials effectively reduced water-soluble Pb at an application rate of 2.5% by weight of the soil. Increase in soil pH from 6.6 to 8.0 was considered to be the main chemistry of Pb immobilization, which was supported by the formation of insoluble Pb species at high pH values as confirmed by the visual MINTEQ thermodynamic model. In contrary, water-soluble Cu was increased in the lime-based waste material-treated soils when compared to the untreated soil. This was likely attributed to the formation of soluble Cu?CDOC (dissolved organic carbon) complexes as all lime-based waste materials applied increased DOC contents in the soil. Therefore, care must be taken in selecting the appropriate amendment for immobilizing metals in shooting range soils. 相似文献
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本文简要介绍了豫北某地较为丰富的岩溶水资源及其氯化物升高的趋势，通过对制碱废渣的静溶和淋溶试验，分析了碱渣淋滤液的产生过程，同时分析了碱渣堆放场与该市岩溶水中氯离子浓度升高的关系，这将对渣场以后的废渣处理及周围的环境质量评价有极其重要的意义。 相似文献
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The concentration and areal distribution of selected metals (Pb, Zn, Cu, Cd, Ni, Fe, and Cr) in the sediments of the Calabar River were studied to determine the extent of anthropogenic input and to estimate the effects of dumping industrial waste materials into the river. The concentrations of Pb, Zn, and Cu indicate relatively moderate pollution mainly on the left-hand side of the river while Ni, Cr, Co, Cd, and Fe levels are below values found to have adverse effects on the lives of marine biota. High metal contents are found close to industrial establishments and so enhanced metal concentrations are related to industrial sewage and metal leaching from garbage and solid waste dumps. 相似文献
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Stefania Da Pelo Elodia Musu Rosa Cidu Franco Frau Pierfranco Lattanzi 《Journal of Geochemical Exploration》2009,100(2-3):142-152
The Furtei gold mine in Sardinia (Italy) exploits a volcanic-hosted high-sulphidation epithermal deposit. Large amounts of materials derived from exploitation are present in open pits, waste rock dumps and cyanidation tailings impoundment. Mineralized rocks in outcrops and waste dumps contain significant amounts of sulphides (mainly pyrite and enargite). These materials have a high potential for acid drainage generation and release of toxic elements (notably Cu and As, but also Al, Ni, Co and Cd) as pointed out by laboratory leaching tests and in agreement with chemical composition of waters draining the mining area, that show pH as low as 2, up to 180 mg/L Cu, up to 5 mg/L As, and up to 788 mg/L Al. On the other hand, leaching solutions and waters interacting with mineral assemblages of the propylitic alteration zone (mainly composed of chlorite, quartz, and calcite, with relic magmatic plagioclase) show higher pH, and lower metal loads. Leachates from cyanidation tailings show variable pH (between 6.2 and 9.7, depending on sulphide content in tailings); cyanide concentration varies between 110 µg/L and about 3 mg/L, whereas contents of toxic elements in leachates are, with the exception of Hg, within the limits of Italian regulations for non-dangerous industrial wastes. Reclamation plans provide for confinement of tailings within specific repositories. This measure should effectively reduce the environmental impact of these materials. Reclamation plans should also include an adequate management of other high-sulphide wastes. 相似文献
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对湘中桃江锰矿废矿堆的废石进行了主量元素、稀土元素、微量元素和重金属元素的地球化学分析。野外观察及分析结果表明:组成废矿堆的岩石主要是赋矿围岩中奥陶统黑色页岩和原生碳酸锰矿石。这些废石富含Cu、Pb、Zn、Cr、Tl、Sb、U等重金属元素。废石暴露地表而遭受风化分解,导致Sc、V、Cr、U、Cd、Th等重金属元素淋滤释出,在废石样品中均表现出不同程度的迁移特征,且以V、Cd、U的迁移性最为强烈。此外,黑色页岩中Ni、Cu、Zn、Pb、Tl、Sb也明显发生淋失。这些重金属元素如Cd、Tl等毒性极强,进入矿区周围不断积聚,便可能对环境造成严重的影响。故对区内分布的废矿堆作为重金属污染源应高度重视。 相似文献
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Richard Martel Timothy James Robertson Minh Quan Doan Sonia Thiboutot Guy Ampleman Arthur Provatas Thomas Jenkins 《Environmental Geology》2008,53(6):1249-1259
Energetic materials contamination was investigated at the former Explosives Factory Maribyrnong, Victoria, Australia. Spectrophotometric/high
performance liquid chromatography (HPLC) analysis was utilised to delineate a 5 tonne crystalline 2,4,6-trinitrotoluene (TNT)
source in a former process waste lagoon that was found to be supplying contaminant leachate to the surficial clay aquitard
with a maximum-recorded concentration of 7.0 ppm TNT. Groundwater within underlying sand and gravel aquifers was found to
be uncontaminated due to upward hydraulic gradients resulting in slow plume development and propagation. Adsorption and microcosm
test results from a parallel study were used as input parameters to simulate aqueous TNT transport in the clay aquitard using
ATRANS20 software. The simulated TNT plume was localised within a few metres of the source, and at steady state, though leaching
rate calculations suggest that without mitigation or other changes to the system, persistence of the source would be approximately
2,000 years. Remediation strategies may involve removal of the near surface source zone and infilling with an impermeable
capping to impede leaching while facilitating ongoing natural attenuation by anaerobic degradation. 相似文献
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《Applied Geochemistry》2003,18(3):395-408
Arsenopyrite-rich waste from a former metalliferous mine were spread out over the sloping side of a deep valley after processing. Over the past 30 a, they have been subjected to rainfall and acid water originating from the abandoned mine galleries. This intensive leaching has led to the formation of thin layers of As–Fe crusts on the tailings surface acting as a cement. X-ray diffraction and SEM coupled with EDS determined that jarosite was present in all mineral samples and could contain a small amount of As (∼5.7 wt.%). In addition EMPA and Raman microspectroscopy characterised the presence of amorphous As(V) Fe hydrates as well as rare arsenate minerals (e.g. scorodite). Raman microspectroscopy in particular identified a preponderance of goethite or hematite within the mineral framework of the tailings materials that is likely to sorb recalcitrant As species. The characterisation of the components of the tailings enable the identification of their evolution, shows the progressive decrease of their As-content and emphasises the consequences of the temporary trapping of As in the very acidic and oxidising conditions prevailing in such environments. Resinous amorphous material was identified as the richest in As with As ∼17.1 wt.%. This material evolved toward more crystallised phases (e.g. goethite, jarosite) which contained less As (3.2 wt.%<As <5.7 wt.%). Paragenesis showed the progressive release of As with the crystallisation evolution of the As-trapping material. 相似文献
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铜矿采矿废石重金属环境污染的淋溶实验研究——以安徽铜陵凤凰山矿田药园山铜矿床为例 总被引：2，自引：0，他引：2
本文基于凤凰山铜矿田药园山矿床采矿废石的淋溶实验研究,着重探索表生环境下影响重金属淋滤迁移的因素,分析重金属在采矿废石中迁移转化的机制。动态淋滤实验考查了重金属从两种采矿废石中淋出的浓度与淋溶液的pH值、淋滤时间以及淋出液酸度的关系。结果表明,采矿废石中重金属淋滤强度随酸度的增加而逐渐增强,而淋滤出的重金属浓度并不总是随时间的延长而递减,同时实验研究也表明,淋溶采矿废石的排放水不一定都是酸性的。因此,在评价矿山环境污染以及治理过程中要对当地雨水的平均pH值、所排放采矿废石的岩性以及废石的堆放时间进行综合考虑。 相似文献
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During stabilization or demobilization of contaminants in solid waste materials, different approaches can be taken, which also can be combined: (1) sufficient long-term buffer capacity can be provided, according to the environmental conditions; (2) permeability for dissolved contaminants can be reduced by secondary mineral precipitations or by soft gels injected into the pore space of the waste body; and (3) new formations of ‘reservoir minerals' can incorporate potential pollutants in their internal structure. Emphasizing the geochemical engineering approach, two examples are presented from the field of water management, both focussing on the demobilization of arsenic species. The first example (after Driehaus, W., 1994. Arsenentfernung mit Mangandioxid und Eisenhydroxid in der Trinkwasseraufbereitung. Vol. 133, Ser. 15, VDI-Reports, Düsseldorf, 117 pp.) relates to the problems during purification of arsenic-rich raw water, suggesting the potential application of iron and manganese oxide minerals as oxidizing agents and mineral lattice structures for the elimination of arsenic. In the second example, contaminated sludges from water treatment plants were investigated for their leaching characteristics and long-term stability. A pH-stat test procedure was used to assess the leaching characteristics of metals at typical pH values. Due to the presence of iron and manganese oxides pentavalent arsenic is protected against conversion into the mobile trivalent form at neutral to low pH. Experimental data suggest that co-disposal with reducing organic matter and alkaline stabilization material or wastes could negatively influence the binding properties and, therefore, should be avoided. 相似文献