Elements Of Environmental Concern Research Articles

A comparative evaluation of enrichment of trace elements in South African and Australian coals using SRXRF

In this study, coals imported from South Africa and Australia were characterized and quantified by an accelerator based X-ray emission technique viz., Synchrotron Radiation X-ray Fluorescence (SRXRF). Twelve trace metallic analytes (V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, and Pb) and four minor elements (K, Ca, Ti, and Fe) were quantified by SRXRF. Elements of environmental concern, V, Cr, Co, Sr, and Pb were found to be enriched with respect to Clarke's world coal values. Correlation analysis reveals that most of the enriched trace elements in both the studied coals have organic affinity rather than inorganic affinity except Cr. Elements were clustered into three groups by hierarchical cluster analysis based on their chemical affinities.

Assessment of resource potential from mine tailings using geostatistical modeling for compositions: A methodology and application to Katherine Mine site, Arizona, USA

The mining industry, in most cases, targets a specific valuable commodity that is present in small quantities within large volumes of extracted material. After milling and processing, most of the extracted material and the effluents are stored as waste (tailings) in impoundments, such as dams or waste dumps, or are backfilled into underground mines. In time, tailing materials may become an issue of environmental and health concern due to the hazardous elements, ions, and oxides contained within the waste material. In addition, handling and storage of such waste in dams may pose the risk of dam failure with catastrophic consequences to nature and nearby communities. On the other hand, tailings may offer potential as secondary sources of critical elements (CEs), including rare earth elements (REEs), which may have been overlooked during primary production and processing. Therefore, treating mine tailings as a resource has economic and environmental benefits by reducing the waste from new and historical mine sites through remining. One of the critical steps for taking advantage of these benefits is to spatially quantify the resources and the pollutants, which require the application of adequate data analysis and modeling methods, often to compositional geochemical data. Utilizing adequate methods is especially important for correctly quantifying resource potential, as the quantities will often be at low concentrations.This work presents quantification of resource potential (Au, Ag, Cu, Zn, Pb) and elements of environmental concern (Hg and As) from the tailings of a historic mine site, Katherine Mine, AZ, USA. Data reported by the U.S. Bureau of Mines (USBM) after extensive field campaigns in the 1990s, including sampling from tailing impoundment and surrounding areas for geochemical characterization and geophysical surveys, were used. First, compositional data (CoDa) analysis was employed to explore associations of sampling locations, geochemical parts, and the clustering of samples. Next, sequential Gaussian simulation (SGSIM) was applied to samples that showed a genetic link to tailing material after isometric log-ratio transformation (ilr) and mix/max autocorrelation factor (MAF) transformation for spatial modeling and uncertainty evaluation. Geostatistical results revealed spatial variability of concentrations within the tailing area. Uncertainty evaluation based on realizations indicated that Cu (14.27–20.01 t), Zn (44.23–76.23 t), and Pb (22.56–38.28 t) are the most abundant elements within a 5 %–95 % interval, followed by Ag and Au (~5.3 and 0.18 t, at 50th percentile), respectively. Of the elements of health concern, As was found to be ~4.8 t (50th percentile) in the tailing area. The work also showed that ~0.51 t As, 0.005 t Hg, 0.020 t of Au, and 0.62 t of Ag were carried to Lake Mohave by an ephemeral stream called Katherine Wash, which transects the tailings.

Multi-elemental profile and enviromagnetic analysis of moss transplants exposed indoors and outdoors in Italy and Belgium

Air pollution represents one of the major concerns worldwide, fueled by the increasing urbanization and related PM production worsening air quality in open air as well as in confined environments. In the present work, exposure to atmospheric metal pollution was investigated in 20 paired indoor (I)-outdoor (O) sites located in two urban areas of Italy and Belgium, by chemical (ICP-MS) and magnetic (saturation isothermal remanent magnetization, SIRM) analyses of Hypnum cupressiforme moss exposed in bags. After 12 weeks, the elemental profiles of the moss material exposed in the two countries largely overlapped, except for some elements which specifically accumulated in Belgium (Ag, As, Cd, Mo, Pb and Sb) and in Italy (Ca, Mg, Co, Cr, Sr, Ti and U). Element concentrations were higher in moss exposed outdoors, with the Italian sites mostly showing a terrigenous footprint, and the Belgian sites mostly affected by elements of environmental concern (e.g., As, Pb, Sb). The Indoor/Outdoor ratios (mostly lower than 0.75) indicated indoor pollution as strongly affected by outdoor pollution, although specific elements could be of indoor origin or magnified in indoor environments (e.g., Al, Ag, Cd and Co). In line with the chemical analysis, the SIRM signal was significantly higher in outdoor than indoor moss material. A positive, significant correlation was observed between SIRM and several accumulated elements indicating SIRM analysis as a powerful tool to predict the level of metal pollution. Moss bags were confirmed as a useful and versatile tool to highlight metal contamination even in confined environments, an essential prerogative in the perspective of the evaluation of the total exposure risk for humans to these pollutants.

Elemental Composition and Organic Petrology of a Lower Carboniferous-Age Freshwater Oil Shale in Nova Scotia, Canada.

A 59 m-thick section of a freshwater oil shale interbedded with marlstone of Lower Carboniferous (Tournaisian) age from the Big Marsh area in Antigonish Basin, Nova Scotia, Canada, was examined using reflected light microscopy, Rock-Eval pyrolysis, X-ray diffractometry analysis, inductively coupled plasma-mass spectrometry for elemental analysis, and prompt γ for boron concentration. The oil shale was deposited in a lacustrine environment based on geology, sedimentology, variation in organic matter, and boron content (28–54 ppm). Organic petrology classified the oil shale into three broadly distinct types. Type A oil shale is a coastal facies shale containing terrestrially derived macerals, such as vitrinite and inertinite, sporinite, with some lamalginite, and amorphous bituminous matrix. Type B oil shale was deposited in a shallow-water facies and contains mostly lamalginite and some vitrinite and sporinite. Type C oil shale is a relatively deep-water facies, associated with open-water Torbanite-type oil shale and contains mostly Botryococcus colonial telalginite. The oil shale is thermally mature (Tmax is 441–443 °C). Total organic carbon (TOC) varies from 5.8 to 7.3 wt %, and the hydrogen index is between 507 and 557 mg HC/g TOC. The rate of sedimentation as determined by the Th/U ratio indicates possibility of three sedimentation periods: an irregular but mostly slow rate of sedimentation from the base of the section up to 68 m, followed by a regular and slow rate between 68 and 53 m, and a regular and fast rate between 53 m and the top of the section. The higher Th/U ratio during deposition of the shallow-water facies was due to the input of allochthonous U. The redox conditions, as reflected in the variation of Cr to Mo, U, and Ni + V, indicate that the oil shale was deposited under suboxic–dysoxic conditions. The high organic productivity by phytoplankton and bacteria is characterized by a low Cr and high V/Cr ratio and suboxic conditions. In contrast, the well-oxygenated and uniform, warm-temperature upper water level supports a dysoxic environment. Variation of Sr/Ca vs Mn/Ca ratios indicates that most samples have low values, a characteristic of colder water and high terrigenous influx. The post-Archean Australian shale (PAAS)-normalized rare earth elements (REEs) follow three trends. Type A oil shale has the highest concentration of total REEs (648 ppm) and light REEs (LREEs, 605 ppm) as compared with type C (269 and 233 ppm), which are less than half of type A. Type B oil shale has the lowest total REEs (184 ppm) and LREEs (152 ppm). The concentration of heavy REEs decreased from 43 ppm in type A oil shale to 36 ppm in type C oil shale. Comparison of PAAS-normalized REEs for the three oil shale types indicates a reduction of the negative Eu anomaly with depth, which is possibly related to sedimentary sorting as a result of accumulation of fine sediments in the deeper water zone of the lake. The concentration of most elements of environmental concern is similar to and/or lower than the world shale. However, there are instances of higher concentrations of hazardous elements (e.g., As, Cd, Mo, and Se).

Kinetic Analysis of the Thermal Decomposition of a Synthetic Mercury Jarosite

Jarosites are widely used in the hydrometallurgical industry of zinc to eliminate iron and other impurities contained in the concentrates. However, these compounds can also incorporate elements of significant environmental concern such as Tl+, Hg2+, Pb2+, Cd2+, Cr(VI), and As(V). In this work, the characterization of a synthetic mercury jarosite and its thermal decomposition kinetics are reported. XRD and FTIR analyses confirm that a mercury jarosite—Hg0.40(H3O)0.2]Fe2.71(SO4)2.17(OH)4.79(H2O)0.44—was successfully synthesized. Four mass loss events were observed by thermogravimetric analysis at 290 °C, 365 °C, 543 °C, and 665 °C. The third event corresponds to mercury decomposition into mercury oxide, whilst the forth is related to the jarosite to hematite transformation determined by X-ray diffraction starting at around 600 °C. According to the kinetic parameters (activation energy and frequency factor) of the thermal decomposition process, the fourth stage required the highest energy (Ea = 234.7 kJ∙mol−1), which corresponds to elimination of sulfur and oxygen from the jarosite lattice. Results show that jarosite-type compounds have the capability to incorporate heavy metals into their structure, retaining them even at high temperatures. Therefore, they can be used as a remediation strategy for heavy metals, such as mercury and others elements of environmental concern.

Mineral matter and trace elements in ashes from a high-arsenic lignite fired power plant in Inner Mongolia, China

The distribution, enrichment, and environmental influence of trace elements and mineral matter in fly ash (FA), bottom ash (BA), and flue gas desulfurization gypsum (FGDG) from a high arsenic coal-fired power plant in Inner Mongolia, China were studied by X-ray diffraction spectrometry (XRD), X-ray fluorescence spectrometry (XRF), field scanning electron microscopy equipped with energy dispersive X-ray spectrometry (FSEM-EDX), atomic fluorescence spectroscopy (AFS), and inductively coupled plasma-mass spectrometry (ICP-MS).The results showed that mineral matter in FA included quartz, mullite, and gypsum, and that in BA included quartz, enstatite, magnetite, and hematite. The arsenic content in the lignites reached 44.4 μg/g, which was much higher than the global average content of lignite. Most of the trace elements in lignite, except for Mo, Sb, and W, had enrichment trends in the fine grade samples. Arsenic is a toxic element enriched in FA compared with the world lignite ash, while there are several elements of environmental concern are depleted elements (Mo, Cd, Ba, and U). The Cs and Hf are also enriched elements in FA, where Hf showed a significant enrichment. The contents of most trace elements in the smaller particles of FA were higher than those in the larger particles, except for Y and Re. The arsenic content in BA was evidently lower than that in FA, which was 24.4 μg/g, and the trace elements enriched in the smaller particles of BA included Li, Zn, Ga, Rb, Mo, Cd, In, Sb, Cs, Nd, Tl, Pb, Bi, and Th. With the exceptions of As, Sr, Cd, and Sb, the amount of trace elements in flue gas desulfurization gypsum was much lower than that in average Chinese soil. Because the fly ash was stacked for a long time, arsenic and several other trace elements leached into soil surrounding the fly ash dump. As a results the elemental content of old fly ash is less than those collected in this study, which indicates the soil in vicinity need to be monitored continuously for their possible environmental effect.

Geochemical indices and regression tree models for estimation of ambient background concentrations of copper, chromium, nickel and zinc in soil

Geochemical ratios between elements of environmental concern and Fe have been recommended for estimation of “background” concentrations of Cr, Cu, Ni and Zn in soil. However, little research has occurred to assess the consistency of geochemical ratios across soils developed in different environments. Broad application of generic geochemical ratios could result in under or over estimation of anthropogenic impacts to soil and subsequent inaccurate assessment of risk to the environment. A soil survey was undertaken in Victoria, Australia, including collection of samples (n = 622) from surface (0–0.1 m below ground level) and sub-surface (0.3–0.6 m below ground level) soils, overlying Tertiary-Quaternary basalt, Tertiary sediments and Silurian siltstones and sandstones. Samples were analyzed for metals and soil physical and chemical properties (particle size, cation exchange capacity, organic matter and pH). Geochemical correlations between elements in soils from different parent materials and environments were compared against geochemical relationships reported in Australia and internationally. Ratios of Cr and Fe were relatively consistent across parent materials, and comparable to published models for estimation of background Cr. Conversely, ratios between Cu, Ni, and Zn with Fe, were variable between soils developed in different weathering environments and/or soil depths. Alternative regression equations and rule based regression tree models were developed as an improved means for prediction of ambient background Cu, Ni and Zn concentrations in soil. Ambient background concentrations of Ni and Cr were predictable across parent materials and depths, allowing these models to be extended to soils across Australia and potentially internationally.

Synergies in elemental mobility during weathering of tetrahedrite [(Cu,Fe,Zn)12(Sb,As)4S13]: Field observations, electron microscopy, isotopes of Cu, C, O, radiometric dating, and water geochemistry

Tetrahedrite [(Cu,Fe,Zn)12(Sb,As)4S13] is commonly present in many ore deposits and may be transferred to mining waste. Here, we describe the behavior of all elements in tetrahedrite during oxidative dissolution in a natural oxidation zone at Piesky (Slovakia), this being a long-term analogue of weathering of tetrahedrite-rich mining wastes. Electron microprobe work identified initial, early, advanced, and mature stages of weathering. The initial stages include formation of secondary covellite and chalcocite, the following stages only oxidic products, divided into greenish masses and brown veinlets. Both of them are nanocrystalline mixtures of minerals. The masses are Cu-Sb-As-rich and consist of a nanocrystalline pyrochlore phase. The veinlets are Fe-Sb-As rich and contain tripuhyite, goethite, and pyrochlores. Quantitative elemental budgets show that some elements (Zn, S, Ni, Co) are rapidly lost whereas others (especially Cu and As) are retained and form copper arsenates in the mature stages of weathering. About 10% As and almost 50% of Sb are lost during weathering, likely released into water; some Sb is stored in secondary minerals such as camérolaite, cualstibite, or tripuhyite. Light carbon isotopic composition (δ13C down to −11.1‰) document significant biological contribution for C in the secondary minerals. Copper isotopes become progressively heavier during weathering (from initial δ65Cu of −2.45‰ in tetrahedrite up to 4.3‰ in some azurite samples but −6.3‰ in covellite and chalcocite), documenting cyclic removal of light copper isotopes into covellite and chalcocite. The observation of elemental synergies during weathering of tetrahedrite shows that the solubility and mobility of As is controlled by copper arsenates, not by iron oxides, in an environment rich in tetrahedrite but poor in pyrite. Antimony, another element of environmental concern, is mostly released into water and creates low-concentration anomalies in stream sediments and soils.

Determination of ultratrace (

There is on-going concern regarding fugitive emissions of trace elements from mining and upgrading of the Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, but remarkably few quantitative elemental data about the resource itself exists. By exploring advances in analytical techniques, an inductively coupled plasma sector field mass spectrometry (ICP-SFMS) method was developed for the determination of trace and ultratrace amounts (<0.1mg/kg) of several elements of environmental concern (Ag, As, Be, Bi, Cd, Pb, Sb and Tl) in bulk ABS and respective bitumen and mineral fractions as separated materials. Samples (n=7) averaged 86±4% mineral matter and 12±3% bitumen. High pressure microwave digestion employing HNO3-HBF4 yielded good recoveries (100±20%) for Ag, As, Be, Bi, Cd, Mo, Ni, Pb, Re, Sb, Tl and V in certified reference materials (NIST 1635, NIST 2711). The distribution of elements within the ABS was dichotomous, with V, Ni, Mo and Re predominantly found in the organic fraction (bitumen) and Ag, As, Be, Bi, Cd, Pb, Sb, and Tl predominantly found in the mineral residue. Trace amounts of As and Pb (0.1–2.0mg/kg), plus ultratrace amounts of Ag, Bi, Cd, Sb and Tl (<0.1mg/kg) were found in the bitumen. Despite filtration (<0.45µm), the bitumen fraction also contained trace amounts of lithophile elements (Be, Co, Ga, Sc, Y, Sm, Dy, Th), which suggested that the occurrence of Ag, As, Be, Bi, Cd, Pb, Sb, and Tl in bitumen was associated with ultrafine clays. Our demonstration of a distinct separation of the ABS trace elements into organic (V, Ni, Mo, Re) and mineral fractions (effectively all other trace elements) may have profound consequences regarding emissions of trace elements to the environment from the industrial development of this resource in northern Alberta.

Metal transport and remobilisation in a basin affected by acid mine drainage: the role of ochreous amorphous precipitates.

Metal-polluted mine waters represent a major threat to the quality of waters and sediments in a downstream basin. At the confluence between acidic mine waters and the unpolluted waters of the Gromolo Torrent (Liguria, North-West Italy), the massive formation of an ochreous amorphous precipitate takes place. This precipitate forms a soft blanket that covers the torrent bed and can be observed down to its mouth in the sea. The aim of this work is to evaluate the dispersion of metals in the Gromolo Torrent basin from the abandoned Cu-Fe sulphide mine of Libiola to the Ligurian Sea and to assess the metal remobilisation from the amorphous precipitates. The mineralogy of the superficial sediments collected in the torrent bed and the concentrations of different elements of environmental concern (Cu, Zn, Cd, Co, Cr, Mn, Ni, Pb, As, and Sb) were therefore analysed. The results showed that the precipitates contain high concentration of Fe, Al, Cu, and Zn, significantly modifying the bulk chemistry of the Gromolo Torrent sediments. In order to evaluate the possible remobilisation of ecotoxic elements from the amorphous precipitates, bulk leaching tests were performed with both deionised and seawater. Bulk leaching tests with deionised water mobilised primarily high Pb amounts, but also relatively high concentrations of Fe, Al, Cu, and Zn are released in the leachate. In seawater tests, Fe, Al, Cu, and Zn were released in smaller amounts, while other elements like Mn, Cd, Co, and Ni increased in the released fraction. Pb was still strongly released as in deionised water experiments. The results show that the interaction of precipitates and seawater can remobilise high concentrations of metals, thus affecting the surrounding environment.

Spatial distribution of major and trace elements in a mining dam: sources and relationships among elements of environmental concern

The concentration of major and trace elements have been determined in sediments samples taken from a mining dam, located in the upper area of the Tinto River basin (SW Spain). This dam, built to fulfil water needs for mining operations, is now completed clogged by accumulation of fine sediments. The results obtained for vertical and horizontal distribution of chemical elements showed highest average concentrations of Fe and Al, both with 10 %, and S (about 4 %). Toxic elements, such as As and Pb occur also with high concentrations (2515 and 5172 mg/kg, respectively). Determination of Enrichment Factors (EF) showed that sediments are enriched in elements related with the massive sulphide ore bodies and subsequent acid mine drainage processes. The elements Pb and As are that of major environmental concern, with enrichment factors higher than 10. Application of cluster analysis put in evidence the main sources of elements, allowing for the modelling of the origin of the accumulated matter. Therefore, in addition to contributions from sulphide (Fe, S) and gangue (Al, Mg), there are grouping of elements mobilized from phyllosilicates and feldspars, (e.g. Ca and K) as well as a specific group that reflects the geochemical affinity of rare earth elements in such acidic environment. Moreover, the way how elements are grouped testify the heterogeneity of geological contributions as well as the mining cycles over 4000 years of mining history in this worldwide known river basin.

Variable contribution of functional prey groups in diets reveals inter- and intraspecific differences in faecal concentrations of essential and non-essential elements in three sympatric avian aerial insectivores: A re-assessment of usefulness of bird faeces in metal biomonitoring

Aerial insectivores through their insect diet can contribute to biotransfer of elements across habitats. We investigate the relationship between dietary composition as expressed by the contributions of six functional invertebrate prey groups (primarily of agriculturally subsidised invertebrates characteristic of agricultural areas in temperate regions of Europe) and concentrations of essential (Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Co) and non-essential (As, Cd, Pb) elements of environmental concern in the faeces of nestlings of three species of avian aerial insectivores – Common Swift Apus apus, Barn Swallow Hirundo rustica and House Martin Delichon urbicum – which breed sympatrically and use apparently similar resources of flying insect prey. There were significant differences between the species for 7 of the 12 elements (Ca, Zn, Cu, Co, As, Pb, Cd); these differences were attributable to the variable dietary composition, even though the concentrations of the elements varied enormously between the faecal samples from the individual species. Partial correlation analysis between the biomass (expressed in mg dry weight) of the six functional prey groups and faecal concentrations of elements showed the highest number of significant relationships for toxic metals (As, Pb and Cd). The results of the General Regression Model explaining faecal element concentrations revealed the different explanatory power of the effects of PCA (of six functional prey groups) dietary scores. A significant fit of GRM was obtained for 7 elements (Na, Mg, Fe, Mn, As, Pb, Cd) for Barn Swallows, 2 elements (Cu, As) for House Martins and 1 element (Mn) for Common Swifts. Overall, the results confirmed our predictions that the biomass of consumed coprophilous taxa and insects from crop habitats was positively correlated with the faecal concentrations of toxic elements. Unexpectedly, however, the faecal samples (primarily those of Common Swifts) that contained many oil-seed rape insect pests had lower Ca, Pb and Cd levels and a higher As level. Our study implies that the cross-boundary transfer of contaminants, primarily non-essential elements, by aerially foraging birds through the considerable accumulation of their faeces has potential consequences for the local biogeochemical cycle and environmental quality.

Cumulative effect of foliar application of copper oxychloride on Pb content in black tea

Copper oxychloride was found as one of the sources of lead contamination in tea as this fungicide is being widely used in tea fields to control the blister blight disease. In India, there is no specification for this heavy metal in copper oxychloride formulations. Commercial brands of copper oxychloride were collected from market and analyzed for lead (Pb) an element of environmental concern. Results were compared with limits prescribed by Food and Agricultural Organization (FAO) of United Nations with a view that these results could be used for fixing limits of heavy metal impurities in national level for the copper oxychloride formulations. Field trials were initiated using the lead contaminated copper oxychloride and in combination with hexaconazole. The study indicates lead contaminated copper oxychloride is one of the sources for lead contamination in black tea. The accumulation of lead content in tea was positively correlated with the application of contaminated copper oxychloride formulations.

Geochemistry of terrestrial oil shale from the Lunpola area, northern Tibet, China

Abstract The Lunpola oil shale is the largest oil shale resource in Tibet. Twenty-four samples of oil shale, mudstone, and dolomite were collected from the Lunpola oil shale for mineralogical and trace element analyses. The vertical distribution and mode of occurrence of trace elements in this terrestrial oil shale were also discussed. Oil shale samples from the Lunpola area have high TOC contents (5.1–10.6%), high ash yields (74.8–84.7%), low total sulfur contents (0.19–1.03%), and high shale oil contents (5.0–10.3%). The major minerals in the oil shale samples are clays, quartz, calcite and dolomite, with minor quantities of feldspar, siderite, hematite, magnesite and pyrite. Other minerals such as halite, zeolite, barite, anhydrite, and mirabilite were detected in some oil shale samples. The contents of As, Ba, Be, Bi, Cd, Ce, Cs, Hg, La, Li, Mo, Nd, Pb, Pr, Rb, Se, Sm, Th, U, W, and Zr are enriched from 1.30 to 125 times as compared to their average crust abundance (Clarke values), whereas the other elements are slightly higher or lower than their respective Clarke values. Compared to common Australian oil shale, the Lunpola oil shales contain higher As, Ba, Be, Ce, Co, Cs, Ga, Gd, Hf, Nb, Nd, Pb, Pr, Rb, Sc, Sm, Sn, Th, and Zr, but lower Cd, Cu, Lu, Mo, Ni, Se, Sr, U, V, and Zn. Elements associated with organic matter and/or Fe-sulfides are highly enriched in all oil shale deposits, suggesting that their speciation in oil shale is governed by general processes (e.g., high organic matter content and anoxic environment), whereas elements associated with clay minerals exhibit various enrichments indicating that their speciation in oil shale is governed by individual geochemical mechanisms (e.g., source rocks). The elements in the Lunpola oil shale may be classified into three groups of associations according to their modes of occurrence. Group A elements (TiO 2 , Sc, Hf, Zr, Be, Li, W, V, Zn, SiO 2 , Al 2 O 3 , Rb, Ga, Sn, Cr, Ta, Cs, K 2 O, Th, Na 2 O, REEs, and ash yield) have high positive correlations with ash yield and a mainly inorganic affinity. Group B elements (As, TOC, MnO, Ni, Fe 2 O 3 , Cd, Co, Cu, Mo, Se, MgO, Bi, Pb, and Hg) show a negative correlation with ash yield, and most elements possibly have a likely organic affinity and/or Fe-sulfide affinity. Group C elements (Sr, CaO, U, and P 2 O 5 ) show a weak or negligible correlation with ash yield (with the exception of CaO). Elements of environmental concern (As, Bi, Hg, Mo, Pb, Se, and U) are present in high contents, and are clustered in the second association, i.e. they are hosted mainly in Fe-sulfides and/or organic matter.

Mineralogical and geochemical investigations of silicate-rich mine waste from a kyanite mine in central Virginia: implications for mine waste recycling

A kyanite mine in central Virginia produces a silicate-rich waste stream which accumulates at a rate of 450,000–600,000 tons per year. An estimated 27 million tons of this waste stream has accumulated over the past 60 years. Grain size distribution varies between 1.000 and 0.053 mm, and is commonly bimodal with modes typically being 0.425 and 0.250 mm and uniformity coefficients vary from 2.000 to 2.333. Hydraulic conductivity values vary from 0.017 to 0.047 cm/s. Mineralogy of the waste stream consists of quartz, muscovite, kyanite and hematite. Muscovite grains have distinct chemical compositions with significant Na2O content (1.12–2.66 wt%), TiO2 content (0.63–1.68 wt% TiO2) and Fe content, expressed as Fe2O3 (up to 1.37 wt%). Major element compositions of samples were dominated by SiO2 (87.894–90.997 wt%), Al2O3 (6.759–7.741 wt%), Fe2O3 (1.136–1.283 wt%), and K2O (0.369–0.606 wt%) with other components being <1.000 wt%. Elements of environmental concern (V, Cr, Ni, Cu, Zn, As, Ag, Sn, Sb, Ba, Hg, Tl, and Pb) were detected; however, the concentrations of all elements except Ni were below that of the kyanite quartzites in the region from which the waste is derived. Both major and trace element compositions indicate minimal variation in composition. The waste stream has potential for recycling. Muscovite is suitable for recycling as a paint pigment or other industrial applications. Muscovite and hematite are commonly intergrown and are interpreted to be material where much of the elements of environmental concern are concentrated. Reprocessing of the waste stream to separate muscovite from other components may enable the waste stream to be used as constructed wetland media for Virginia and nearby states. Recycling of this mine waste may have a positive impact on the local economy of Buckingham County and aid in mitigation of wetland loss.

Major and trace elements in plants and soils in Horton Plains National Park, Sri Lanka: an approach to explain forest die back

Forest die back has been observed from 1980s in the montane moist forest of Horton Plains in the Central Sri Lanka for which the aetiology appears to be uncertain. The concentration levels of Na, K, Ca, Mg, Fe, Mn, Cu, Ni, Zn and Pb in canopy leaves, bark and roots, which were collected from dying and healthy plants of three different endemic species, Calophyllum walkeri, Syzygium rotundifolium and Cinnamomum ovalifolium, from three different die back sites were studied. Soils underlying the plants were also analyzed for their extractable trace metals and total contents of major oxides. Analysis of dead and healthy plants does not show any remarkable differences in the concentrations of studied trace elements. The results show that there is a low status of pollution based on the concentrations of chemical elements of environmental concern. Extractable and total trace element analysis indicates a low content of Ca in soils due to high soil acidity that probably leads to Mg and Al toxicity to certain plants. Relatively high Al levels in the soil would affect the root system and hamper the uptake and transport of essential cations to the plant. It therefore seems that the forest declining appears to be a natural phenomenon, which occurs due to the imbalance of macro and micronutrients in the natural forest due to excessive weathering and the continuous leaching of essential elements.

99/02823 Removal of ash, sulfur, and trace elements of environmental concern from eight selected Illinois coals, USA

99/02823 Removal of ash, sulfur, and trace elements of environmental concern from eight selected Illinois coals, USA

Removal of Ash, Sulfur, and Trace Elements of Environmental Concern from Eight Selected Illinois Coals*

Release analysis (RA) and float-sink (F-S) data were generated to assess the beneficiation potential of washed coals from selected Illinois coal preparation plants through the use of advanced physical cleaning at −60 mesh size. Generally, the F-S process removed greater amounts of ash, sulfur, and trace elements of environmental concern from the coals than the RA process, indicating that the cleanability of Illinois coals by advanced methods can be estimated best by F-S testing. At an 80%-combustibles recovery, the ash yield in the clean F-S products decreased by 47-75%, relative to the parent coals. Average decreases for the elements As(67%), Cd(78%), Hg(73%), Mn(7l%), and P(66%) exceeded the average decrease for ash yield (55%). Average decreases for other elements were: Co(3l%), Cr(27%), F(39%), Ni(25%), Pb(50%, S(28%), Sb(20%), Se(39), Th(32%), and U(8%). Only Be was enriched (up to 120%) in the clean products relative to the parent coals. These results suggested that the concentration of elements with relatively high atmospheric mobilities (As, Cd, F, Hg, Pb, and Se) during coal combustion can be reduced substantially in Illinois coals through the use of advanced physical cleaning. Advanced physical cleaning can be effective also for the removal of inorganic S. Environmental risks from the emission of other elements with enrichment or relatively low cleanabilities could be small because these elements generally have very low concentrations in Illinois coals or are largely retained in solid residues during coal combustion.

Selected Elements and Radionuclides in Thermal Coals from Alberta, Canada

This preliminary study reports on the concentration of selected elements of environmental concern, such as Be, Cd, F, Hg, Pb, and radionuclides, in subbituminous coals used exclusively for power generation in Alberta. Results show that the concentrations of these elements and radioactive nuclides in the coals studied are low compared to typical concentrations in world coals. The coals are "clean," suitable for use in coal-fired power plants, and their utilization has little impact on the environment. The potential fate of the elements and radionuclides is interpreted only in general terms, mainly by referring to previous studies on the behavior of trace elements and radionuclides during combustion.

Characterization and correlation of soil and plant selenium in some range and coal mine environments of Wyoming

Abstract Selenium (Se) has been recognized as an element of environmental concern because of its natural occurrence and potential toxicity to plants, animals, and humans. Range and coal mine (reclaimed and abandoned) soils were studied using various soil extracts, including saturated paste, hot water, ammonium bicarbonate‐DTPA (AB‐DTPA), and phosphate in order to compare the Se extraction efficiency of these reagents and to characterize the soil‐plant Se correlations in these environments. Soil extraction data indicated the order of Se extractability was phosphate > AB‐DTPA > hot water > saturated paste. The saturated paste‐extractable Se was found to be typically very low. Statistically significant correlations between phosphate‐, AB‐DTPA‐, and hot water‐extractable Se were observed irrespective of the type of environment. Selenium extracted by these reagents indicated certain relationships, such as phosphate ≈ 2 AB‐DTPA, phosphate ≈ 5 hot water, and AB‐DTPA ≈ 3 hot water. Selenium content of shrub veget...