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1.
In Brazil, intense coal exploitation activities have led to environmental deterioration, including soil mortification, water contamination, loss of ecosystem, and atmospheric contamination. In addition,considerable quantities of sulfur-rich residues are left behind in the mining area; these residues pose grave environmental issues as they undergo sulfide oxidation reactions. When sulfur oxides come in contact with water, extreme acid leachate is produced with great proportions of sulfate, and hazardous elements(HEs), which are identified as coal drainage(CMD). CMD is an environmental pollution challenge, particularly in countries with historic or active coal mines. To prevent CMD formation or its migration, the source must be controlled; however, this may not be feasible at many locations. In such scenarios, the mine water should be collected, treated, and discharged. In this study, data from 2005 to2010 was gathered on the geochemistry of 11 CMD discharges from ten different mines. There are several concerns and questions on the formation of nanominerals in mine acid drainage and on their reactions and interfaces. The detailed mineralogical and geochemical data presented in this paper were derived from previous studies on the coal mine areas in Brazil. Oxyhydroxides, sulfates, and nanoparticles in these areas possibly go through structural transformations depending on their size and formation conditions. The geochemistry of Fe-precipitates(such as jarosite, goethite, and hematite) existent in the CMD-generating coal areas and those that could be considered as a potential source of hazardous elements(HEs)(e.g., Cr) were also studied because these precipitates are relatively stable in extremely low pH conditions. To simplify and improve poorly ordered iron, strontium, and aluminum phase characterization, field emission scanning electron microscopy(FE-SEM), high-resolution transmission electron microscopy(HR-TEM), micro-Raman spectroscopy, and X-ray diffraction(XRD) and sequential extraction(SE) studies were executed on a set CMD samples from the Brazilian mines. This study aimed to investigate the role of both nanomineral and amorphous phase distribution throughout the reactive coal cleaning rejects profile and HEs removal from the water mine to provide holistic insights on the ecological risks posed by HEs, nanominerals, amorphous phases, and to assess sediments in complex environments such as estuaries.  相似文献   

2.
《地学前缘(英文版)》2020,11(6):2053-2060
Air pollution monitoring is one of the most important features in contamination risk management. This is because many of the compounds contained within air pollution present a serious risk both for the preservation of open air cultural heritage and for human health. New particle formation is a major contributor to urban pollution, but how it occurs in cities is often puzzling. As more and more people enjoy an increased quality of life through outdoor activity, managing outdoor air quality is vital. This study presents the application of a low-cost system for monitoring the current level of road traffic passengers’ exposure to particulate air contamination. The global rise in tourism also leads to apprehension about its probable destructive influence on various aspects of global preservation. One of the major risks encountered by tourists, stemming from modes of transport, are nanoparticles (NPs) (≤100 ​nm) and ultra-fine particles (UFPs) (100–1000 ​nm) consisting of potentially hazardous elements (PHEs). This study examines Steen Castle, a medieval fortress located in Antwerp, Belgium. Significant NPs with PHEs, were found in the air sampled in this area. The self-made passive sampler (LSPS) described in this study, consisting of retainers specially designed for advanced microscopic analysis, is used for the first time as a simple way to characterize the surrounding atmospheric contamination caused by NPs and UFPs, without the need of other commonly employed more expensive particulate focused active samplers such as cascade impactors. This study aims to assess the result of the utilization of a low-cost, LSPS, to determine outdoor NPs and UFPs in a Belgian urban (Steen Castle) and rural area (Fort van Schoten). This work is the first to detail the usefulness of LSPS for the evaluation of Belgium’s outdoor air for NPs and UFPs, which contain PHEs.  相似文献   

3.
The role of both natural weathering and anthropogenic pollution in controlling the distribution of major oxides and several trace elements in soils, stream sediments, and rocks of the Fiume Grande catchment was evaluated. The contents of major oxides and trace elements in soils appear to be governed by weathering and pedogenetic processes, although the use of fertilizers in agriculture could also partly affect K2O and P2O5 contents. Stream sediments have concentrations of major oxides (except CaO) very similar to soils, as relevant amounts of soil materials are supplied to the stream channels by erosive phenomena. In contrast, stream sediments have concentrations of Cr, Co, Ni, Zn, As, and Pb significantly higher than those of soils, probably due to different conditions and rates of mobility of these elements within the three considered matrices and/or disposal of wastes in the drainage network. Comparison of the concentrations of PHEs in soils with the maximum admissible contents established by the Italian law shows that these limits are too restrictive in some cases and too permissive in other ones. The approach of setting these limits with no consideration for the local geological–geochemical framework may lead to improper management of the territory and its resources. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.  相似文献   

4.
Coal mine rejects and sulfide bearing coals are prone to acid mine drainage (AMD) formation due to aqueous weathering. These acidic effluents contain dissolved trace and potentially harmful elements (PHEs) that have considerable impact on the environment. The behavior of these elements in AMD is mainly controlled by pH. The focus of the present study is to investigate aqueous leaching of mine rejects for prediction of acid producing potential, rates of weathering, and release of PHEs in mine drainage. Mine reject (MR) and coal samples from the active mine sites of Meghalaya, India typically have high S contents (1.8–5.7% in MR and 1.7–4.7% in coals) with 75–90% of the S in organic form and enrichment of most of the PHEs in rejects. Aqueous kinetic leaching experiments on mine rejects showed high acid producing potential and release of trace and potentially harmful elements. The elements (Sb, As, Cd, Cr, Co, Cu, Pb, Mn, Ni, V and Zn) in mine sample leachates are compared with those in mine waters. The concentrations of Al, Si, P, K, Ti, Mn, Fe, Co, Ni, Cu, Zn and Pb are found to increase with leaching time and are negatively correlated with pH of the solution. The processes controlling the release of these elements are acid leaching, precipitation and adsorption. The critical loads of PHEs in water affected by AMD are calculated by comparing their concentrations with those of regulatory levels. The Enrichment Factors (EFs) and soil pollution indices (SPIs) for the elements have shown that PHEs from coal and mine reject samples are mobilized into the nearby environment and are enriched in the associated soil and sediment.  相似文献   

5.
This study is one of very few dealing with mining waste contamination in high altitude, tropical-latitude areas exploited during the last century. Geochemical, mineralogical and hydrological characterizations of potentially harmful elements (PHEs) in surface waters and sediments were performed in the Milluni Valley (main reservoir of water supply of La Paz, Bolivia, 4000 m a.s.l.), throughout different seasons during 2002–2004 to identify contamination sources and sinks, and contamination control parameters. PHE concentrations greatly exceeded the World Health Organization water guidelines for human consumption. The very acidic conditions, which resulted from the oxidation of sulfide minerals in mining waste, favoured the enrichment of dissolved PHEs (Cd > Zn ? As ? Cu ∼ Ni > Pb > Sn) in surface waters downstream from the mine. Stream and lake sediments, mining waste and bedrock showed the highest PHE content in the mining area. With the exception of Fe, the PHEs were derived from specific minerals (Fe, pyrite; Zn, Cd, sphalerite, As, Fe, arsenopyrite, Cu, Fe, chalcopyrite, Pb, galena, Sn, cassiterite), but the mining was responsible for PHEs availability. Most of the PHEs were extremely mobile (As > Fe > Pb > Cd > Zn ∼ Cu > Sn) in the mining wastes and the sediments downstream from the mine. pH and oxyhydroxides mainly explained the contrasted availability of Zn (mostly in labile fractions) and As (associated with Fe-oxyhydroxides). Unexpectedly, Pb, Zn, As, and Fe were significantly attenuated by organic matter in acidic lake sediments.  相似文献   

6.
土壤和沉积物中天然有机质(NOM)稳定性问题受到关注,主要是因为NOM的稳定性直接影响到大气中CO2的平衡与全球气候变化。此外,天然有机质还影响着土壤和沉积物中矿物的表面反应性、污染物的环境行为与生物有效性。因此,本综述在详细介绍土壤和沉积物中NOM稳定性矿物学机制研究的理论与方法的同时,也简略介绍了NOM的组成结构与反应性,并着重强调NOM/矿物微界面过程作用机制的重要性。许多研究表明,土壤和沉积物中NOM稳定性的矿物学机制主要包括矿物表面吸附和物理包裹。本综述目的是,介绍矿物保护的稳定NOM的分离、特性及其分析测定方法与技术,并且强调NOM稳定性矿物学保护机制系统性研究的重要性,以搞清矿物学保护机制在土壤和沉积物中NOM稳定保持中的贡献与重要性以及矿物学保护机制对天然有机质稳定性的调控作用,从而提高对土壤和沉积物环境生态的地球化学、矿物学的认识水平。  相似文献   

7.
Oxic limestone beds are commonly used for the passive removal of Mn(II) from coal mine drainage (CMD). Aqueous Mn(II) is removed via oxidative precipitation of Mn(III/IV) oxides catalyzed by Mn(II)-oxidizing microbes and Mn oxide (MnOx) surfaces. The relative importance of these two processes for Mn removal was examined in laboratory experiments conducted with sediments and CMD collected from eight Mn(II)-removal beds in Pennsylvania and Tennessee, USA. Sterile and non-sterile sediments were incubated in the presence/absence of air and presence/absence of fungicides to operationally define the relative contributions of Mn removal processes. Relatively fast rates of Mn removal were measured in four of the eight sediments where 63–99% of Mn removal was due to biological oxidation. In contrast, in the four sediments with slow rates of Mn(II) removal, 25–63% was due to biological oxidation. Laboratory rates of Mn(II) removal were correlated (R2 = 0.62) to bacterial biomass concentration (measured by phospholipid fatty acids (PLFA)). Furthermore, laboratory rates of Mn(II) removal were correlated (R2 = 0.87) to field-scale performance of the Mn(II)-removal beds. A practical recommendation from this study is to include MnOx-coated limestone (and associated biomass) from an operating bed as “seed” material when constructing new Mn(II)-removal beds.  相似文献   

8.
Members of the animal kingdom, including humans, can ingest soil either involuntarily or deliberately, the latter practice being known as geophagy or geophagia. This paper briefly documents the often significant quantities of soil that can be consumed, but discusses in detail the importance of this ingestion in supplying mineral nutrients and potentially harmful elements (PHEs) to consumers of earth materials. Whilst geophagia is recognised as a multi-causal behaviour, a prevalent explanation is the ‘nutritional hypothesis’ where the deliberate consumption of soil is attributed to an attempt to regulate a mineral nutrient imbalance such as sodium deficiency. When soils encounter digestive fluids, chemical elements can be solubilised and are potentially available for absorption, sometimes to an extent where toxicity symptoms are evident. In grassland agricultural systems, two main pathways of chemical elements are recognised, the soil–plant–animal flow being complemented by the more direct soil–animal transfer of mineral nutrients and PHEs. In locations where the pasture herbage absorbs very low concentrations of chemical elements relative to the soil content, ingested soil particles can often be observed to be the major source of mineral nutrients/PHEs consumed by livestock. However, further research is required in quantifying the bioaccessibility – defined as the fraction that is soluble in the gastrointestinal tract and is potentially available for absorption – of soil-elements to animals. In this respect, regarding human nutrition, for more than a decade considerable work has been undertaken on the development of in vitro bioaccessibility tests (IVBA) that can rapidly and inexpensively estimate this portion of chemical elements from ingested soils. Work to date has demonstrated that significant amounts of some mineral nutrients, especially iron, can be bioaccessible to humans, as can quantities of PHEs such as lead. Paradoxically, some ingested soils can also result in mineral nutrient deficiency problems in humans and other members of the animal kingdom attributable, for example, to the adsorptive properties of earth materials that can effectively bind chemical elements.  相似文献   

9.
This study was carried out to analyze the distribution and soil–plant transfer of selected potential harmful elements (PHEs: As, Hg and Zn) in soils and in two edible horticultural crops (cabbage, Brassica oleracea L., and tomato, Lycopersicon esculentum Mill). randomly sampled in kitchen gardens/small farms around one of the most important and old Portuguese industrial areas (Estarreja Chemical Complex-ECC). The results show that 46% and 11.5% of the soils present high total As (12–532 mg/kg) and Hg (6.6–13.65 mg/kg) concentrations that exceed protective health Canadian soil quality guidelines. Soil As and Zn available fractions are also of concern for groundwater and crops contamination as more than 84% of the samples were above the trigger value proposed by the German legislation for both elements (0.4 and 2 mg/kg, respectively). In the horticultural crops the cabbage leaves concentrate more the PHEs (max.: 3.5, 0.08 and 746 mg/kg dw for As, Hg and Zn, respectively) than the tomato fruit (max.: 0.4, 0.02 and 82 mg/kg dw, respectively). The highest concentration of the study PHEs in soils and horticultural crops were found near sewage outlets that are chiefly related to historical industrial activities mostly from arsenopyrite roasting and a chloralkali plant. The values of estimated bioaccumulation and bioconcentration coefficients suggested exclusion mechanisms for transfer of As to edible cabbage and tomato tissues and cabbage Zn tolerance capacity. The concentration of the PHEs in the edible horticultural crops tissues were not directly related with respective soil total concentration or available fractions, specially for As and Hg. Sampling locations with the highest concentrations of As, Hg, Zn in soil and vegetable foodstuffs should be sites to foregoing research and human daily intakes should be investigated in order to evaluate potential health risks.  相似文献   

10.
《Applied Geochemistry》2001,16(11-12):1387-1396
The purposes of this study are to (i) determine the geochemical characteristics of Imgok creek impacted by acid mine drainage (AMD) generated from abandoned coal mines, (ii) to assess the pollution of heavy metals in the stream sediments and soils, and (iii) to identify the chemical form of Fe precipitates collected in the study area where there are 4 abandoned coal mines, which belong to the Grangreung coal field at the eastern part of Korea. AMD generated from mine adits and coal refuse piles shows low pH, and high concentrations of Fe, Al and SO4, especially in the Youngdong coal mine. In Imgok creek, pH values increased, and total dissolved solids (TDS) values decreased with distance. The concentrations of toxic heavy metals and major cations except Fe decreased by dilution, but the concentration of Fe decreased rapidly due to the formation of precipitates. The quality of groundwater samples did not exceed the Korean drinking-water standard. In the stream sediments, the concentrations of Fe are relatively high in the Youngdong tributary and Imgok creek, but the concentrations of heavy metals are similar to those of unpolluted sediments. Pollution indices of agricultural soils range from 0.28 to 0.47. Yellowish red Fe precipitates collected in the study area turned out to be amorphous or poorly crystallized minerals (determined by X-ray diffraction patterns and Feox/Fetot ratios) and to contain chemically bonded SO4 and OH [determined by infra-red (IR) spectral analysis]. With these, the mol ratios of Fe/S ranging from 4.6 to 6.1 determined by electron probe micro-analysis (EPMA) in precipitates strongly support the existence of schwertmannite.  相似文献   

11.
During the geological survey and prospecting, helium and hydrogen are recognized indicators of minerals, deep-seated faults, seismic activity, and ascending deep fluids. Their anomalous concentrations also serve as a marker of metamorphic processes. Helium survey is applied for tracing deep-seated faults and mapping permeable zones. In this work, the first results of gas geochemical survey in marine sediments and water to study the distribution of helium and hydrogen and their relation with the seismic activity of some geological structures in the southwestern Sea of Okhotsk and northern Sea of Japan. Anomalies of these gases (He up to 60 ppm, H up to 120 ppm) were identified in the hydrate-bearing sediments in the fault zones. It was also found that helium concentrations in the water column of the Tatar Strait are higher than in the studied area of the Sea of Okhotsk, possibly, due to the difference in geological structure and seismotectonic activation. Moreover, coal layers could be a significant source of methane in the gashydrate-bearing layers of the Tatar Strait.  相似文献   

12.
Roof successions above two coal seams from the Mansfield Formation (Lower Pennsylvanian) in the Indiana portion of the Illinois Basin have been studied with regard to sedimentary structures, organic petrology and organic geochemistry. The succession above the Blue Creek Member of the Mansfield Formation is typical of the lithologies covering low-sulphur coals (< 1%) in the area studied, whereas the succession above the unnamed Mansfield coal is typical of high-sulphur coals (>2.%). The transgressive-regressive packages above both seams reflect the periodic inundation of coastal mires by tidal flats and creeks as inferred from bioturbation and sedimentary structures such as tidal rhythmites and clay-draped ripple bedforms. Geochemistry and petrology of organic facies above the Blue Creek coal suggest that tidal flats formed inland in fresh-water environments. These overlying fresh water sediments prevented saline waters from invading the peat, contributing to low-sulphur content in the coal. Above the unnamed coal, trace fossils and geochemical and petrological characteristics of organic facies suggest more unrestricted seaward depositional environment. The absence of saline or typically marine biomarkers above this coal is interpreted as evidence of very short periods of marine transgression, as there was not enough time for establishment of the precursor organisms for marine biomarkers. However, sufficient time passed to raise SO42− concentration in pore waters, resulting in the formation of authigenic pyrite and sulphur incorparation into organic matter.  相似文献   

13.
Mitrovica, northern Kosovo, is the site of some of the highest Pb concentrations reported in human populations; exemplified by Pb concentrations in scalp hair of up to 130 μg g−1 and widely-publicized of Pb-related ill-health and mortality amongst internally displaced populations. High human Pb burdens are accompanied by elevated concentrations of potentially harmful elements (PHEs) in soils and house dust within the city, which has a long history of mining and metallurgy. In this study enrichment-levels for PHEs in soils are quantified and compared to environmental quality guidelines and a statistically-derived estimation of background concentration. In addition, Pb isotopes (207Pb/206Pb, 208Pb/206Pb) are used to characterise the isotopic signatures of potential point sources of Pb and a mixing model employed to quantify the contribution of sources to Pb present in soils, house dust, and the scalp hair of children and young people. Pb isotopic evidence suggests that Pb in surface soils and house-dust is predominantly sourced from historical deposition of Pb-containing aerosols from metal smelting, with lower contributions from wind-blown dispersal of metalliferous waste. Pb present in scalp hair is interpreted as the result of non-occupational exposure and the ingestion and/or inhalation of Pb-enriched surface soil and house dust. This study represents one of the very few instances where this type of geochemical tracing technique has been successfully applied to definitively identify the source of Pb present within biological samples. The results of this study are of particular relevance to environmental management and highlight the human health risk posed by the legacy of now inactive mining and metallurgy in addition to the challenge posed in mitigating the risk posed by diffuse soil pollution.  相似文献   

14.
As a result of over-erosion of soils, the fine particles, which contain the majority of nutrients, are easily washed away from soils, which become deficient in a host of components, accumulating in lakes. On one hand, the accumulation of nutrients-rich sediments are a problem, as they affect the quality of the overlying water and decrease the water storage capacity of the system; on the other hand, sediments may constitute an important resource, as they are often extremely rich in organic and inorganic nutrients in readily available forms. In the framework of an extensive work on the use of rock related materials to enhance the fertility of impoverish soils, this study aimed to evaluate the role on the nutrients cycle, of particles recycling processes from the watershed to the bottom of a large dam reservoir, at a wet tropical region under high weathering conditions. The study focus on the mineralogical transformations that clay particles undergo from the soils of the drainage basin to their final deposition within the reservoir and their influence in terms of the geochemical characteristics of sediments. We studied the bottom sediments that accumulate in two distinct seasonal periods in Tucuruí reservoir, located in the Amazonian Basin, Brazil, and soils from its drainage basin. The surface layers of sediments in twenty sampling points with variable depths, are representative of the different morphological sections of the reservoir. Nineteen soil samples, representing the main soil classes, were collected near the margins of the reservoir. Sediments and soils were subjected to the same array of physical, mineralogical and geochemical analyses: (1) texture, (2) characterization and semi-quantification of the clay fraction mineralogy and (3) geochemical analysis of the total concentration of major elements, organic compounds (organic C and nitrogen), soluble fractions of nutrients (P and K), exchangeable fractions (cation exchange capacity, exchangeable bases and acidity) and pH(H2O).There is a remarkable homogeneity in the sedimentary distribution along the reservoir in terms of the texture and mineralogy of the clay fraction and of the chemistry of the total, soluble and exchangeable phases. These observations contrast with the physical, morphological and chemical heterogeneity of the soils and the setting lithology. Most of the sediments has a higher contribution of fine-grained material and the mineralogy of the clay fraction is dominated by kaolinite in soils and kaolinite and illite in sediments, followed by lesser amounts of gibbsite, goethite, and metahaloisite and by small/vestigial contents of chlorite and smectite. The sediments are mainly inherited from the watershed but there exist marked differences between the accumulated sediments and their parent materials. These differences mainly come from the selective erosion of fine-grained particles and the extreme climatic conditions which enhance complex transformations of mineralogical and chemical nature. Compared with the parental soils, the reservoir sediments show the following differences: (1) enrichment in fine-grained and less dense inorganic particles, (2) aggradative mineralogical transformations, including enrichment in clay minerals with higher cationic adsorption and exchange capacity, (3) degradation of the crystalline structure of Fe- and Al-oxides (goethite, gibbsite), (4) increase in easily leached elements (Mg, Ca, P, K, Na) and decrease in chemically less mobile elements (Si, Fe) and (5) higher contents of organic carbon, nitrogen, and soluble forms of P and K, mainly concentrated in the clay fraction. These transformations are extremely important in the nutrients cycle, denoting that sediments represent an efficient sink for nutrients from the over-erosion of soils. Mineral and organic compounds can permanently or temporarily sequester these nutrients, recycling them and enhancing their availability through the slow release of components from relatively loose crystal structures. These processes can easily explain the enrichment in soluble and exchangeable forms of elements such as P, K, Ca or Mg. This study conclude that the particles recycling in a large tropical dam reservoir which receives high fluxes of allochthonous nutrients, has an important role in the good quality of sediments for agricultural use and in the profitable use of this technology to recover depleted soils in remediation projects in regions near large hydroelectric plants.  相似文献   

15.
古土壤记录了丰富的古气候和古环境信息,然而古土壤受后期地质作用影响常不易被正确地识别。甘肃张掖彩丘是白垩纪早期发育的彩色地层,目前详细的地层序列尚未建立。张掖彩丘表现为红色、黄色、灰色、紫色等多种颜色交替变化,通常被认为是河湖相沉积或洪积相沉积,然而野外考察发现大量的古土壤特征。野外观察识别古土壤主要从根迹、土壤结构和土壤发生层等方面,主要表现为红色根迹或青灰色晕状根迹,半干旱环境下形成的钙质淀积层,土壤在干湿交替环境下形成的粘土滑擦面,土壤发生层之间的过渡边界。本文通过对张掖彩丘地层的系统考察,建立了较为详细的厚760 m的地层序列,根据古土壤的发育特征,识别出14种不同类型的古土壤,整个彩丘地层共计156个古土壤剖面,是独特的古土壤序列。14种古土壤类型与现代土壤类型对照,并与国际土壤分类对比,类比的现代土壤类型主要出现在南亚的亚热带或热带气候条件,说明白垩纪早期比现在更为温暖。根据古土壤发育程度序列,结合古土壤特征和地层特点,将古气候变化分成4个阶段,依次是湿润(0~268 m)、半干旱(268~550 m)、湿润(550~740 m)、干旱(740~760 m)阶段。张掖彩丘古土壤的系统识别和发育程度序列的建立为进一步古气候研究奠定基础。  相似文献   

16.
The aim of this study was to determine the sources and contamination characteristics of polycyclic aromatic hydrocarbons (PAHs) in various environmental media in a karst underground river system. For this purpose, air, underground river water, sediment, and soil samples were collected from a typical underground river in southern China in the dry and wet seasons of 2013–2014, and the compositional spectra, distribution, and ratio characteristics of 16 PAHs were determined for comparative analysis. The results show that three 2–3-ring PAHs (naphthalene, phenanthrene, and fluoranthene) mainly occur in air and underground river water. In sediments and soils, 4–6-ring PAHs are the main components. The PAH concentrations in the air in the wet season are clearly greater than those in the dry season, while it is the opposite in the underground water. Seasonal differences in the concentration of PAHs in the sediments and soils are minor. The concentrations of PAHs in the environmental media overall showed variation in the following order: upstream < midstream < downstream, and this is related to pollutant discharge, adsorption, etc. The main source of PAHs in the upstream area is the combustion of grass, wood, and coal, while it is petroleum in the midstream area, and combustion of grass, wood, coal, and petroleum near the outlet of the underground river. It is necessary to change the energy structure in the study area, improve the efficiency of environmental protection facilities, reduce the emission in vehicle exhaust, and control pollution by PAHs at their sources.  相似文献   

17.
This study identified soft–sediment deformation structures(SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo–dammed lake at Tashkorgan, northeastern Pamir. The observed deformation structures include sand dykes, liquefied diapir and convolute structures, gravity induced SSDS, and thixotropic pillar and tabular structures. We conducted a preliminary study on the morphology, formation and trigger mechanisms of pillar and tabular structures formed by liquefaction of underlying coarse sand and thixotropy of the upper silty clay. The regional tectonic setting and distribution of lacustrine strata indicate that the most probable trigger for the SSDS in lacustrine sediments was seismic activity, with an approximate earthquake magnitude of M6.0; the potential seismogenic fault is the southern part of the Kongur normal fault extensional system. AMS 14 C dating results indicate that the SSDS were formed by seismic events occurring between 26050±100 yr BP and 22710±80 yr BP, implying intense fault activity in this region during the late Pleistocene. This study provides new evidence for understanding tectonic activity and regional geodynamics in western China.  相似文献   

18.
The deterioration of environmental conditions is the major contributory factor to poor health and quality of life that hinders sustainable development in any region.Coal mining is one of the major industries that contribute to the economy of a country but it also impacts the environment.The chemical parameters of the coal,overburden,soil and sediments along with the coal mine drainage(CMD)were investigated in order to understand the overall environmental impact from high sulphur coal mining at northeastern coalfield(India).It was found that the total sulphur content of the coal is noticeably high compared to the overburden(OB)and soil.The volatile matter of the coal is sufficiently high against the high ash content of the soil and overburden.The water samples have a High Electrical Conductivity(EC)and high Total Dissolve Solid(TDS).Lower values of pH,indicate the dissolution of minerals present in the coal as well as other minerals in the mine rejects/overburden.The chemical and nano-mineralogical composition of coal,soil and overburden samples was studied using a High Resolution-Transmission Electron Microscopy(HR-TEM),Energy Dispersive Spectroscopy(EDS),Selected-Area Diffraction(SAED),Field Emission-Scanning Electron Microscopy(FE-SEM)/EDS,X-ray diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),Raman and Ion-Chromatographic analysis,and Mossbauer spectroscopy.From different geochemical analysis it has been found that the mine water sample from Ledo colliery has the lowest pH value of 3.30,Tirap colliery samples have the highest electrical conductivity value of5.40 ms cm~(-1)Both Ledo and Tirap coals have total sulphur contents within the range 3-3.50%.The coal mine water from Tirap colliery(TW-15 B)has high values of Mg~(2+)(450 ppm),and Br~-(227.17 ppm).XRD analysis revealed the presence of minerals including quartz and hematite in the coals.Mineral analysis of coal mine overburden(OB)indicates the presence both of pyrite and marcasite which was also confirmed in XRD and Mossbauer spectral analysis.The presented data of the minerals and ultra/nano-particles present shows their ability to control the mobility of hazardous elements,suggesting possible use in environmental management technology,including restoration of the delicate Indian coal mine areas.  相似文献   

19.
Atmospheric pollution from atmospheric particulate matter (APM) deposition is one of the major sources of potential hazardous elements (PHEs) contamination. In this study, 68 total APM samples were collected from the local areas of southern Xi’an (NW China) during the long-term period of the 2001–2012 dust campaign. The chemical fractionation of PHEs (Cr, Cu, Ba, Sr, As, Pb, and Zn), their contamination levels, and ecological health risk were examined. The mobility sequence based on the sums of the first three fractionations of the modified BCR (the European Community Bureau of Reference) sequential extraction stages was: Cu (77.83 %) > Pb (74.50 %) > Zn (55.40) > Sr (52.93) > Ba (40.89) > Cr (30.09) > As (21.59). The contamination levels of APMs from these sites, calculated from the total content indices ICF, were uniformly moderate in degree. The obtained single-metal model MIMERSS (speciation index) values had allowed for classification of elements as a function of their potential ecological risk as As (64.00 mean value) > Pb (43.86) > Sr (37.50) > Cu (11.53) ? Ba (11.32) > Zn (7.68) > Cr (1.88). The results presented that the toxic As posed a moderate to considerable risk; Pb and Sr varied from low to a moderate risk, while others posed low risk. However, a new developed multi-metal model GRIIERMS (speciation index) indicated that the PHEs in most of the APMs posed moderate ecological risk. The result was consistent with that of ICF indexes. Combined with the US Environmental Protection Agency, we developed models of (ingestion, dermal and inhalation) hazard index (HI), children’s health risk due to PHEs exposure from APM was higher than that for adults. Much attention should be paid to the PHE As (HI = 0.864, close to 1) for children. While, carcinogenic risk for adults was higher than that for children. Although cancer risk because of As, Cr and Pb exposure were within an acceptable range, the PHEs exposed to the highest density of the population in residential and educational villages in south of Xi’an would be much more concerned. The moderate ecological risk and the higher risk for children’s health illustrated that special attention has to be taken to the mentioned PHEs from APMs in the local ecosystem, and their health risk impact should continue to be checked carefully. The new developed GRIIERMS index method was to be useful for risk assessment of PHEs combining with their chemical fractionations.  相似文献   

20.
《Applied Geochemistry》2003,18(7):955-972
This review highlights the major progress over the last decade on characterization of geochemically heterogeneous soil/sediment organic matter (SOM) and the impacts of SOM heterogeneity on sorption and desorption of hydrophobic organic contaminants (HOCs) under equilibrium and rate limiting conditions. Sorption and desorption by soils and sediments are fundamental processes controlling fate and transport of less polar and nonpolar organic pollutants in surface aquatic and groundwater systems. Recent studies have shown that soils and sediments exhibit an array of HOC sorption phenomena that are inconsistent with an early partition model based on an assumption of homogeneous gel-like SOM. Increasing data have revealed that isotherm nonlinearity, varied sorption capacity, sorption–desorption hysteresis, and slow rates of sorption and desorption are characteristics for HOC sorption by soils and sediments. These phenomena have been shown to result from different types of condensed SOM that exhibit capacity limiting sorption processes. Recent findings of glass transition phenomena and the nonlinear HOC sorption by humic acids provide a scientific foundation for drawing an analogy between humic acids and synthetic organic polymers that supports a dual mode model for sorption by soils and sediments. Humic acid is glassy or rigid at temperatures lower than its glass transition temperature and exhibits relatively nonlinear sorption isotherms for HOCs. Fractionation and quantification of SOM indicate that soils and sediments contain significant amounts of black carbon and kerogen of different origins. These particulate organic materials have rigid 3-dimensional structures and are often less polar compared to humic substances. Limited studies show that black carbon and kerogen exhibit nonlinear sorption for HOCs and may dominate the overall nonlinear sorption by soils and sediments.  相似文献   

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