Tailings Site Research Articles

Using strontium isotopes to evaluate the spatial variation of groundwater recharge

Recharge of alluvial aquifers is a key component in understanding the interaction between floodplain vadose zone biogeochemistry and groundwater quality. The Rifle Site (a former U-mill tailings site) adjacent to the Colorado River is a well-established field laboratory that has been used for over a decade for the study of biogeochemical processes in the vadose zone and aquifer. This site is considered an exemplar of both a riparian floodplain in a semiarid region and a post-remediation U-tailings site. In this paper we present Sr isotopic data for groundwater and vadose zone porewater samples collected in May and July 2013 to build a mixing model for the fractional contribution of vadose zone porewater (i.e. recharge) to the aquifer and its variation across the site. The vadose zone porewater contribution to the aquifer ranged systematically from 0% to 38% and appears to be controlled largely by the microtopography of the site. The area-weighted average contribution across the site was 8% corresponding to a net recharge of 7.5 cm. Given a groundwater transport time across the site of ~1.5 to 3 years, this translates to a recharge rate between 5 and 2.5 cm/yr, and with the average precipitation to the site implies a loss from the vadose zone due to evapotranspiration of 83% to 92%, both ranges are in good agreement with previously published results by independent methods. A uranium isotopic (234U/238U activity ratios) mixing model for groundwater and surface water samples indicates that a ditch across the site is hydraulically connected to the aquifer and locally significantly affects groundwater. Groundwater samples with high U concentrations attributed to natural bio-reduced zones have 234U/238U activity ratios near 1, suggesting that the U currently being released to the aquifer originated from the former U-mill tailings.

Metal resistant rhizobia and ultrastructure of Anthyllis vulneraria nodules from zinc and lead contaminated tailing in Poland

ABSTRACTThis present paper studies the response of Anthyllis vulneraria-Rhizobium symbiosis to heavy metal stress. The symbiotic rhizobium bacteria isolated from root nodules of A. vulneraria from zinc and lead wastes were examined in this project. Light microscopy (LM) and transmission electron microscopy (TEM) were used to analyze the nodule anatomy and ultrastructure and conduct a comparison with nonmetal-treated nodules. 16S ribosomal DNA sequence analysis of bacteria isolated from metal-treated nodules revealed the presence of Rhizobium metallidurans and Bradyrhizobium sp. In regard to heavy metal resistance/tolerance, a similar tolerance to Pb was shown by both strains, and a high tolerance to Zn and a lower tolerance to Cd and Cu by R. metallidurans, whereas a high tolerance to Cd and Cu and a lower tolerance to Zn by Bradyrhizobium were found. The nodules of Anthyllis from metal-polluted tailing sites were identified as the typical determinate type of nodules. Observed under TEM microscopy changes in nodules ultrastructure like: (1) wall thickening; (2) infection thread reduction; (3) vacuole shrinkage; (4) synthesis of phenolics in vacuoles; (5) various differentiation of bacteroids and (6) simultaneous symbiosis with arbuscular mycorrhiza fungi could be considered as a form of the A.vulneraria-Rhizobium symbiosis adaptation to metal stress.

Hg in snow cover and snowmelt waters in high-sulfide tailing regions (Ursk tailing dump site, Kemerovo region, Russia)

Gold-bearing polymetallic Cu-Zn deposits of sulphur-pyrite ores were discovered in the Novo-Ursk region in the 1930s. The average content of mercury (Hg) was approximately 120 μg/g at the time.A comprehensive study of Hg distribution in waste of metal ore enrichment industry was carried out in the cold season on the tailing dump site and in adjacent areas. Mercury concentration in among snow particulate, dissolved and colloid fractions was determined. The maximal Hg content in particulate fraction from the waste tailing site ranged 230–573 μg/g. Such indices as the frequency of aerosol dust deposition events per units of time and area, enrichment factor and the total load allowed to establish that the territory of the tailing waste dump site had a snow cover highly contaminated with dust deposited at a rate of 247–480 mg/(m2∙day). Adjacent areas could be considered as area with low Hg contamination rate with average deposition rate of 30 mg/(m2∙day). The elemental composition of the aerosol dust depositions was determined as well, which allowed to reveal the extent of enrichment waste dispersion throughout adjacent areas. The amount of Hg entering environment with snowmelt water discharge was estimated. As a result of snowmelting, in 2014 the nearest to the dump site hydrographic network got Hg as 7.1 g with colloids and as 5880 g as particles. The results obtained allowed to assess the degree of Hg contamination of areas under the impact of metal enrichment industry.

Internal energy ratios as ecological indicators for description of the phytoremediation process on a manganese tailing site

A plant community is an open thermodynamic system. In accordance with the first and second laws of thermodynamics, the total internal energy U of a plant community before reaching equilibrium will increase under natural conditions because of solar energy intake and nutrient uptake. As state functions of a thermodynamic system, enthalpy H, entropy S and Gibbs free energy G are related to U by G + TS = H = U + PV. Increase in U will lead to increases in H, S and G since given volume V and temperature T or pressure P, dG + TdS = dH = dU > 0. The experimental data collected from the plant communities restored on a manganese tailing site confirmed the potential trend of increase in H, S and G of the plant communities with increase in their biomass quantity and biodiversity. The traditional criterion “ΔG < 0” would then be no longer valid as a spontaneity index for description of the ecological process of a growing and developing plant community. Since G/H = 1-T(S/H), given T, G/H will be negatively related to S/H. The number of plant species N is an essential property of a plant community, and as a function of N, the S/H ratio is expected to increase with increase in species richness under natural conditions, resulting in d(S/H) ≥ 0 and d(G/H) ≤ 0. The change in G/H can thus be applied as a thermodynamic parameter to judge the spontaneity of plant community growth and development. The results obtained from the present study showed that both G/H and S/H ratios were useful indicators for description of the ecological restoration process.

Omega-3 fatty acid desaturase gene family from two ω-3 sources, Salvia hispanica and Perilla frutescens: Cloning, characterization and expression.

Omega-3 fatty acid desaturase (ω-3 FAD, D15D) is a key enzyme for α-linolenic acid (ALA) biosynthesis. Both chia (Salvia hispanica) and perilla (Perilla frutescens) contain high levels of ALA in seeds. In this study, the ω-3 FAD gene family was systematically and comparatively cloned from chia and perilla. Perilla FAD3, FAD7, FAD8 and chia FAD7 are encoded by single-copy (but heterozygous) genes, while chia FAD3 is encoded by 2 distinct genes. Only 1 chia FAD8 sequence was isolated. In these genes, there are 1 to 6 transcription start sites, 1 to 8 poly(A) tailing sites, and 7 introns. The 5’UTRs of PfFAD8a/b contain 1 to 2 purine-stretches and 2 pyrimidine-stretches. An alternative splice variant of ShFAD7a/b comprises a 5’UTR intron. Their encoded proteins harbor an FA_desaturase conserved domain together with 4 trans-membrane helices and 3 histidine boxes. Phylogenetic analysis validated their identity of dicot microsomal or plastidial ω-3 FAD proteins, and revealed some important evolutionary features of plant ω-3 FAD genes such as convergent evolution across different phylums, single-copy status in algae, and duplication events in certain taxa. The qRT-PCR assay showed that the ω-3 FAD genes of two species were expressed at different levels in various organs, and they also responded to multiple stress treatments. The functionality of the ShFAD3 and PfFAD3 enzymes was confirmed by yeast expression. The systemic molecular and functional features of the ω-3 FAD gene family from chia and perilla revealed in this study will facilitate their use in future studies on genetic improvement of ALA traits in oilseed crops.

Three-dimensional hydrogeological modeling to assess the elevated-water-table technique for controlling acid generation from an abandoned tailings site in Quebec, Canada

The Manitou Mine sulphidic-tailings storage facility No. 2, near Val D’Or, Canada, was reclaimed in 2009 by elevating the water table and applying a monolayer cover made of tailings from nearby Goldex Mine. Previous studies showed that production of acid mine drainage can be controlled by lowering the oxygen flux through Manitou tailings with a water table maintained at the interface between the cover and reactive tailings. Simulations of different scenarios were performed using numerical hydrogeological modeling to evaluate the capacity of the reclamation works to maintain the phreatic surface at this interface. A large-scale numerical model was constructed and calibrated using 3 years of field measurements. This model reproduced the field measurements, including the existence of a western zone on the site where the phreatic level targeted is not always met during the summer. A sensitivity analysis was performed to assess the response of the model to varying saturated hydraulic conductivities, porosities, and grain-size distributions. Higher variations of the hydraulic heads, with respect to the calibrated scenario results, were observed when simulating a looser or coarser cover material. Long-term responses were simulated using: the normal climatic data, data for a normal climate with a 2-month dry spell, and a simplified climate-change case. Environmental quality targets were reached less frequently during summer for the dry spell simulation as well as for the simplified climate-change scenario. This study illustrates how numerical simulations can be used as a key tool to assess the eventual performance of various mine-site reclamation scenarios.

Modeling groundwater flow and salinity evolution near TSF Żelazny Most. Part I – groundwater flow

Tailings which are by-product of the extraction of various metals (copper, gold, silver, molybdenum, etc.) are often stored in so called Tailings Storage Facilities (TSF), where they are deposited as a soil-water mixture by spigotting. In many cases the water discharged together with tailings to the TSF is rich in salts and other chemical compounds imposing negative pressure to the groundwater environment. Even in the case of total or partial lining of such facilities and well-developed drainage systems to control leaching, some portion of contaminated water often seeps either through the surrounding dams or the bed into adjacent groundwater bodies. Numerical models can be very helpful tools to assess the extent of the contamination and particularly to predict its potential development in the future. This paper and the companion one describe such a numerical model developed for Żelazny Most Tailings Storage Facility (south-west Poland), one of the world’s largest tailings sites. In the first part general information about the facility is provided and a 3D hydrogeological numerical model of the structure is described. Groundwater flow pattern near the facility obtained from numerical simulations is confronted with the measurements from a comprehensively developed monitoring system. Part II will be focused on the modelling of chloride transport in groundwater.

Field study on Re and heavy metal phytoextraction and phytomining potentials by native plant species growing at Sarcheshmeh copper mine tailings, SE Iran

In the present work, we aimed to focus on the identification and characterization of the heavy metal-tolerant plant species growing spontaneously at the tailings site of the Sarcheshmeh copper mine, south of Iran. Our aim was to find the plant species that were potentially useful for phytoextraction purposes. The concentrations of As, Cu, Mo, Ni, Zn, and Re were analyzed in soil as well as in the shoots and roots of plant species separately by an Inductively Coupled Plasma-Optical Emission Spectrometer (ICP–OES). The mean concentrations of As, Cu, Mo, Ni, Zn, and Re in soil were found to be 18.44±13.41, 1280±500.95, 25.06±13.33, 32.9±14.39, 251.82±95.82, and 1.7±0.78 mg kg-1, respectively. The translocation factor (TF) and the bioaccumulation factor (BCF) were defined and used to assess the amount of the elements accumulated in the shoots and roots of each plant species and to evaluate their potential for phytoextraction purposes. Based upon the results obtained and using the most common criteria, T. ramosissima, C. dactylon, A. leucoclada, and Z. fabago could strongly tolerate and extremely accumulate multiple metal(loid)s. Also Salsola kali, C. dactylon, A. leucoclada, and Z. fabago could be classified as hyperaccumulators for Re with TF and BCF greater than one and ten, respectively. The results of this work should be further developed in order to confirm the potential use of these species in phytoextraction programs.

Baseline status of microbial activity on gold tailings facilities in South Africa

In many ways, South Africa’s landscape has been dominated by mining, given that, for so many years this sector has been the mainstay of the South African economy. As such the environmental impacts of these mining activities are one of the greatest globally. These environmental impacts need to be addressed during each phase of environmental planning, especially during mine closure. By investigating the microbial enzymatic activity of tailings associated with different gold mine waste disposal environments in order to distinguish the effects of gold mining on associated ecosystems. This research will exemplify the importance of microbiological enzymatic characteristics as part of rehabilitation assessment criteria. Soil enzymatic and physicochemical analysis were analysed by standard methods and the result emphasised that the tailings materials possess poor microbial enzymatic activities. The baseline soil microbial activity levels of the tailings are dependent on the specific chemical, physical and biological parameters of the tailings materials. The microbial activity of the different gold tailings storage facilities varied greatly. Generally, the microbial enzymatic activity was greater on the surface/rhizosphere zone in the partially revegetated tailings sites. In contrast, the barren tailings had the lowest microbial enzymatic activity, which also had the lowest acidic pH. The low dehydrogenase, β-glucosidase, urease, acid and alkaline phosphatase enzymatic activities observed at these mining sites signifies that tailings materials possess poor microbiological enzymatic characteristics. Consequently, it can be assumed that the soil quality and fertility of these sites are lower because of decreased microbial activity due to the deficit of biodegradable organic matter and limited nutrient cycling. The mine waste disposal environment is devoid of true soil character deprived of macro and micro-nutrients, acidic pH with elevated concentrations of trace metals. Thus, indicating a high degree of soil degradation and poor soil health that affects not only the chemical and physical characteristic of the tailings material but also the microbiological properties. As such, it is clear that the contribution that microbes make to the ecosystems functioning in extreme environments, such as mine waste disposal environments is vastly underrated. Subsequently, microbial processes need to be included into mine rehabilitation practices, hypotheses, models, and interpretation of rehabilitation findings. To conclude, the study provided a microbial baseline status of different gold tailings storage facilities that will provide a platform for future investigations.

Greenhouse Gas Emissions after Application of Landfilled Paper Mill Sludge for Land Reclamation of a Nonacidic Mine Tailings Site.

Large areas of mine tailings are reclaimed by applying organic amendments such as paper mill sludge (PMS). Although mining industries can use PMS freshly generated by paper mills, operational constraints on paper industries make temporary landfilling of this material an unavoidable alternative for the paper industries, creating the most prominent PMS source for mining industries. This study aimed to quantify soil greenhouse gas (GHG) emissions (NO, CO, and CH) after application of landfilled PMS (LPMS; i.e., excavated from a landfill site at a paper mill) and LPMS combined with a seeding treatment of white clover ( L.) on nonacidic mine tailings site prior to reforestation. Soil NO, CO, and CH fluxes were measured after applications of 50 and 100 Mg dry LPMS ha during two consecutive snow-free seasons on two adjacent sites; LPMS was applied once in the first season. The LPMS application increased NO emissions (7.6 to 34.7 kg NO-N ha, comprising 1.04 to 2.43% of applied N) compared with the unamended control during the first season; these emissions were negligible during the second season. The LPMS application increased CO emissions (∼5800 to 11,400 kg CO-C ha, comprising 7 to 27% of applied C) compared with the unamended control on both sites and in both seasons. Fluxes of CH were negligible. White clover combined with LPMS treatments did not affect soil GHG emissions. These new GHG emission factors should be integrated into life-cycle analyses to evaluate the C footprint of potential symbioses between the mining and paper industries. Future research should focus on the effect of PMS applications on soil GHG emissions from a variety of mine tailings under various management practices and climatic conditions to plan responsible and sustainable land reclamation.

The influences of arbuscular mycorrhizal fungus on phytostabilization of lead/zinc tailings using four plant species

ABSTRACTA greenhouse experiment was conducted to investigate the effects of the arbuscular mycorrhizal fungus Funneliformis mosseae on three parameters: Pb, Zn, Cu and Cd accumulation, translocation and plant growth in perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea), showy stonecrop (Hylotelephium spectabile) and Purple Heart (Tradescantia pallida). The purpose of this work is to enhance site-specific phytostabilization of lead/zinc mine tailings using native plant species. The results showed that mycorrhizal fungi inoculation significantly increased plant biomass of F. arundinacea, H. spectabile and T. pallida. The Pb, Zn, Cu and Cd concentrations in roots were higher than those in shoots both with and without mycorrhizae, with the exception of the Zn concentration in H. spectabile. Mycorrhizae generally increased metal concentrations in roots and decreased metal concentrations in shoots of L. perenne and F. arundinacea. In addition, it was found that the majority of the bioconcentration and translocation factors were lower than 1 and mycorrhizal fungi inoculation further reduced these values. These results suggest that appropriate plant species inoculated with mycorrhiza might be a potential approach to revegetating mine tailing sites and that H. spectabile is an appropriate plant for phytostabilization of Pb/Zn tailings in northern China due to its higher biomass production and lower metal accumulation in shoots.

Si-based technologies for reduction of the pollutant leaching from landfills and mine tails

ABSTRACTMonosilicic and polysilicic acids were shown to react with different types of the pollutants. The direction of these reactions can be managed by changing the monosilicic and polysilicic acid concentration in soil or water media. The objective of this study was to determine the effect of Si-treated calcium metallurgical slag and battery slag on the As, Se, Cd, Pb, Ni, Cr, and Hg mobility and bioavailability in mine tailings (Xikuangshan mine, Hunan, China). The results of column experiment showed that the Si-activated slags reduced leaching of As, Se, Cd, Pb, Ni, Cr, and Hg by 13–89% and transformed them into plant-unavailable forms. The greenhouse test has demonstrated that the Si-treated slags provided reinforced plant resistance to heavy metal toxicity and reduced pollutants in barley and pea leaves. Si-treated local solid slags could be used for creating the biogeochemical barriers on the pollutant streams from landfills or mine tailings sites.

Plants from the abandoned Nacozari mine tailings: evaluation of their phytostabilization potential.

Phytostabilization is a remediation technology that uses plants for in-situ stabilization of contamination in soils and mine tailings. The objective of this study was to identify native plant species with potential for phytostabilization of the abandoned mine tailings in Nacozari, Sonora in northern Mexico. A flora of 42 species in 16 families of angiosperms was recorded on the tailings site and the abundance of the most common perennial species was estimated. Four of the five abundant perennial species showed evidence of regeneration: the ability to reproduce and establish new seedlings. A comparison of selected physicochemical properties of the tailings in vegetated patches with adjacent barren areas suggests that pH, electrical conductivity, texture, and concentration of potentially toxic elements do not limit plant distribution. For the most abundant species, the accumulation factor for most metals was <1, with the exception of Zn in two species. A short-term experiment on adaptation revealed limited evidence for the formation of local ecotypes in Prosopis velutina and Amaranthus watsonii. Overall, the results of this study indicate that five native plant species might have potential for phytostabilization of the Nacozari tailings and that seed could be collected locally to revegetate the site. More broadly, this study provides a methodology that can be used to identify native plants and evaluate their phytostabilization potential for similar mine tailings.

Experimental and numerical evaluation of single-layer covers placed on acid-generating tailings

This study focuses on the reclamation work being performed on two former acid-generating tailings sites, located in Quebec, Canada. At both sites, the tailings were partially oxidized due to extended exposure, and the pore water is acidic. The reclamation solution applied to control acid mine drainage is a monolayer cover, made of non acid-generating tailings in one case and a till in the other. The goal of this project was to assess the response of the tailings-cover systems under various conditions. Tailings samples were collected in situ and characterized in the laboratory. Large column tests were conducted to evaluate the hydrogeological and geochemical behaviour of the covered tailings following wetting and drying cycles. The instrumented columns were designed to reproduce some of the existing site conditions and provide representative results for longer term analyses. Volumetric water content, suction, and oxygen concentrations were also monitored over time. The experimental data were used to validate different numerical models including those constructed with Vadose/W (GeoSlope Int.). Additional simulations were conducted under field conditions to evaluate the effect of various influence factors such as the depth of the water table, climatic conditions and the thickness of the cover. The combination of experimental and numerical results show how the behaviour and efficiency of a monolayer cover placed over reactive tailings depend on these factors, highlighting the importance of hydrogeological properties and water table depth. In many instances, the cover materials were prone to desaturation, especially when the water table was deeper than about 2 m below the tailings-cover interface. These results tend to indicate that relatively thin monolayer covers would not be able to prevent oxygen ingress under some of the conditions observed in the field. Desaturation of the cover and/or reactive tailings is due to a combination of drainage and evaporation. In such cases, increasing the thickness of the monolayer cover only has a limited effect. A discussion follows on the practical implications of these laboratory experiments and the numerical simulations for field design of reclamation measures at these two tailings impoundments.

Occupation and land degradation due to mining works: Example of the 'Kolubara' mining basin

The subject of this scientific-research paper is the occupation and land degradation due to mining works in the 'Kolubara' mining basin. The aim of the research is to determine areas exposed to degradation and to display devastated areas along with the possibility of conditions' improvement through the revitalization of certain areas. Additionally, the aim would be the proposal of measures for solving other ecological problems, such as waste, tailings sites and activities to reduce the level of environmental pollution and to conduct the proper monitoring.

锰矿修复区植物生态系统自由能与化学势分析

PDF HTML阅读 XML下载 导出引用 引用提醒 锰矿修复区植物生态系统自由能与化学势分析 DOI: 10.5846/stxb201512032425 作者: 作者单位: 中南林业科技大学,中南林业科技大学,中南林业科技大学,中南林业科技大学,中南林业科技大学,中南林业科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技惠民计划项目（2012GS430203）；国家十二五科技支撑计划项目（2014BAC09B00）；中南林业科技大学研究生科技创新基金项目（CX2015A02） Gibbs free energy and chemical potentials of plant communities in a manganese-ore tailing site undergoing ecological restoration Author: Affiliation: Central South University of Forestry and Technology,Central South University of Forestry and Technology,Central South University of Forestry and Technology,Central South University of Forestry and Technology,Central South University of Forestry and Technology,Central South University of Forestry and Technology Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于热力学理论建立了生态系统Gibbs自由能方程，用以计算湘潭锰矿生态修复区植被系统的自由能（G）和物种化学势（μ）。生态修复区（及对照区）以泡桐（Paulownia fortunei）和栾树（Koelreuteria bipinnata）作为建群植物，总面积为4 hm2，修复区泡桐和栾树的根际施用了含有自试验点废弃矿渣中筛选出的耐性菌株的有机菌肥，目的是为植物生长提供必要养分和降低根际土壤重金属毒性，对照区泡桐和栾树的根际施用了等量的化肥。泡桐和栾树种植后5 a期间，修复区与对照区均自然萌发生长了许多本土植物种类。试验结果表明，修复区植物种类数达到48，为对照区的3.7倍；修复区的总生物量、锰吸收量分别达到23324 kg/hm2和4280 g/hm2，为对照区对应值的20.6和2.6倍；修复区系统自由能G远远大于对照区的值，说明有机菌肥具有显著的改良污染土壤根际环境的效果。修复区和对照区植物种类之间的化学势μ均存在显著差异（P < 0.001），μ值差异范围分别为-3.79-6.76和-3.42-3.59，该一差异反映不同物种适应和修复锰污染环境的能力。G和μ值包含了生态系统生产力、生物多样性，植物种类生长势、重金属富集能力、生态学行为等综合信息，能反映生态系统与立地环境的关系和修复植物的生态学特性，可作为重金属污染区植被修复效果评价和修复植物筛选的重要指标。 Abstract:Matter and energy exchanges constitute the basis of ecological processes. Therefore, ecosystems can be regarded as open thermodynamic systems, with bio-species as key components. The changes in ecosystem states can therefore be measured and compared in terms of Gibbs free energy (G) and chemical potential (μ). Based on thermodynamic theories, an ecosystem Gibbs free energy model was established for calculating the changes in G of plant communities and μ of the plant species, at an ecological restoration site of manganese-ore tailing in the Xiangtan region. The total area of the experimental site, including the control plot, was 4 hectares, which was covered with Paulownia fortunei and Koelreuteria bipinnata as the dominant, transplanted, wood species. The rooting areas of the wood species at the experimental site were amended with organic manure, containing a tolerant bacterium strain isolated from the experimental site's mining waste. Organic manure application was undertaken not only to provide necessary nutrients for plant growth, but also to improve the root growth conditions by reducing the metal toxicity in the rhizosphere. The wood plant species were screened first, and the amending effects of the organic manure were tested in pot experiments before initiating the on-site ecological restoration project. For comparison purposes, an equivalent amount of chemical fertilizers was applied to the control plot. Within a five-year period after transplanting the wood species to the site, native plant species naturally germinated as well, and grew in both the restoration and control sites. Soil and plant samples were collected and analyzed using standard methods. The number of plant species was counted, and the density of each species was estimated at the site. Furthermore, the cover percentage, biomass quantity, and manganese uptake of each plant species were calculated. The number of plant species at the restoration site was 48, which was 4 times that of the control plot. The total dry biomass and manganese uptake at the restoration site was 23,324 kg/hm2 and 4,280 g/hm2, respectively. This was respectively 20.6, and 2.6 times as high as in the control plot. In addition, the plant community's total Gibbs free energy was significantly higher at the restoration site than at the control site. These results indicate that the application of organic manure improved the root growth conditions of the contaminated soil, and that the effects were significant. There were also significant differences in chemical potentials among the plant species at both the restoration and control sites (P < 0.001). The μ values for different plant species ranged between -3.79 to 6.76, and -3.42 to 3.59, respectively, at the restoration and control sites. The μ value reflects the ability of plant species not only to adapt, but also to restore the metal-contaminated environment. As ecosystem properties, both G and μ are functions of biomass, manganese uptake, density, and the number of plant species. The values of G furthermore, comprise integrated information on the productivity and biodiversity of the ecosystem. The values of μ concern the growth potential, heavy metal accumulation capacity, and relevant ecological characteristics of the plant species regarding their mutual competition, inhibition, and symbiosis behaviors under given site conditions. In comparison with traditionally applied hyperaccumulators and biodiversity indices, the G and μ values were found to be appropriate parameters for evaluating the impacts of a site's environment on ecosystem growth. Furthermore, they proved suitable for analyzing the ecological behaviors of the remediation plants. In sum, both G and μ values can be used as important indices for determining the effects of ecological restoration in heavy metal contaminated areas, as well as for the screening of phytoremediation plant species. 参考文献 相似文献 引证文献

Mine tailings influencing soil contamination by potentially toxic elements

The potentially hazardous contents of mine tailings can pose a serious threat to the environment. Tailings dispersed around the abandoned Monica mine (Bustarviejo) in the Autonomous Region of Madrid (Central Spain) were studied to determine the concentration of several potential toxic elements and their geochemical impact in the surrounding soils. A total of 17 surface soil samples were collected from both mixed sulfide mine tailings sites and unmined soils, within a radius of 1900 m from the mine entrance. The processing of minerals (basically arsenopyrite, matildite and sphalerite) produced tailings with a pH as low as 2.9. Elements such as As, Cu, Zn, Cd, Pb, W, Ag, Fe were found in very high concentrations, contaminating the soil to varying degrees (these elements were sometimes 10- to 20-times higher in the tailings than in the unmined soils). Given its short distance and accessibility from such a large city as Madrid, it is of undeniable environmental and educational interest. Among other factors, there is a need for improvements to tailings management strategies.

Water contamination with heavy metals and trace elements from Kilembe copper mine and tailing sites in Western Uganda; implications for domestic water quality

The mining and processing of copper in Kilembe, Western Uganda, from 1956 to 1982 left over 15 Mt of cupriferous and cobaltiferous pyrite dumped within a mountain river valley, in addition to mine water which is pumped to the land surface. This study was conducted to assess the sources and concentrations of heavy metals and trace elements in Kilembe mine catchment water. Multi-element analysis of trace elements from point sources and sinks was conducted which included mine tailings, mine water, mine leachate, Nyamwamba River water, public water sources and domestic water samples using ICP-MS. The study found that mean concentrations (mg kg−1) of Co (112), Cu (3320), Ni (131), As (8.6) in mine tailings were significantly higher than world average crust and were being eroded and discharged into water bodies within the catchment. Underground mine water and leachate contained higher mean concentrations (μg L−1) of Cu (9470), Co (3430) and Ni (590) compared with background concentrations (μg L−1) in un contaminated water of 1.9, 0.21 and 0.67 for Cu, Co and Ni respectively. Over 25% of household water samples exceeded UK drinking water thresholds for Al of 200 μg L−1, Co exceeded Winsconsin (USA drinking) water thresholds of 40 μg L−1 in 40% of samples while Fe in 42% of samples exceeded UK thresholds of 200 μg L−1. The study however found that besides mining activities, natural processes of geological weathering also contributed to Al, Fe, and Mn water contamination in a number of public water sources.

Protecting the environment and public health from rare earth mining

AbstractAs increasing demand for green energy and high‐tech devices grows, so does the rising prospecting of rare earth metals required for their production. Protecting the environment and public health from rare earth element (REE) mining as well as emerging pollutants is urgently required to achieve sustainable development. This study mapped Earth's hidden REE deposits to identify potential contamination hotspots with the aim of preventing its deleterious effects on the environment. We worry that there would be widespread tailing facilities concomitant with serious pollutions, such as the Bayan Obo tailings site, and argue that a tradeoff between the underground REE exploration and environment conservation should be reached as soon as possible.

Content of selected elements and low-molecular-weight organic acids in fruiting bodies of edible mushroom Boletus badius (Fr.) Fr. from unpolluted and polluted areas.

The aim of the study was to (i) investigate the potential of edible mushroom Boletus badius (Fr.) Fr. to accumulate 53 elements from unpolluted acidic sandy soil and polluted alkaline flotation tailing sites in Poland, (ii) to estimate the low-molecular-weight organic acid (LMWOA) profile and contents in fruit bodies, and finally (iii) to explore the possible relationship between elements and LMWOA content in mushrooms. The content of most elements in fruiting bodies collected from the flotation tailings was significantly higher than in mushrooms from the unpolluted soils. The occurrence of elements determined in fruiting bodies of B. badius has been varied (from 0.01 mg kg−1 for Eu, Lu, and Te up to 18,932 mg kg−1 for K). The results established the high importance of element contents in substrate. Among ten organic acids, nine have been found in wide range: from below 0.01 mg kg−1 for fumaric acid to 14.8 mg g−1 for lactic acid. Lactic and succinic acids were dominant in both areas, and citric acid was also in high content in polluted area. The correlation between element contents and the individual and total content of LMWOAs was confirmed.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-016-7222-z) contains supplementary material, which is available to authorized users.