Elevated Concentrations Of Trace Elements Research Articles

Contributions of artifactual materials to the toxicity of anthropogenic soils and street dusts in a highly urbanized terrain

A study was undertaken to test the hypothesis that the presence of fly ash and other artifactual materials (AMs) significantly increases the toxicity of urban soil and street dust. AMs were distinguished as artifacts (artificial particles > 2 mm in size), and particulate artifacts (≤2 mm in size); street dust was the <63 μm fraction of street sediments. Reference artifacts, street dusts, and topsoils representing different land use types in Detroit, Michigan were analyzed for miscellaneous radionuclides, trace elements, magnetic susceptibility (MS), and acetic acid-extractable (leachable) Pb. Background levels were established using native glacial sediments. Street sediments were found to have a roadside provenance, hence street dusts inherited their contamination primarily from local soils. All soils and dusts had radionuclide concentrations similar to background levels, and radiological hazard indices within the safe range. Artifacts, fly ash-impacted soils and street dusts contained elevated concentrations of toxic trace elements, which varied with land use type, but none produced a significant amount of leachable Pb. It is inferred that toxic elements in AMs are not bioavailable because they are occluded within highly insoluble materials. Hence, these results do not support our hypothesis. Rather, AMs contribute to artificially-elevated total concentrations leading to an overestimation of toxicity. MS increased with increasing total concentration, hence proximal sensing can be used to map contamination level, but the weak correlation between total and leachable Pb suggests that such maps do not necessarily indicate the associated biohazard. Home site soils with total Pb concentrations >500 mg kg−1 were sporadically toxic. Thus, these results argue against street dust as the local cause of seasonally elevated blood-Pb levels in children. Lead-bearing home site soil tracked directly indoors to form house dust is an alternative exposure pathway.

New insights into environmental controls on the occurrence and abundance of Group I alkenones and their paleoclimate applications: Evidence from volcanic lakes of northeastern China

The distinctive long-chain alkenones (LCAs) produced by Group I Isochrysidales from freshwater and oligohaline lakes have great potential for quantitative paleotemperature reconstructions. The widespread application of sedimentary Group I LCAs, however, is hampered by an incomplete understanding of the environmental controls on the occurrence of Group I LCAs in freshwater lakes. The correspondence between Group I LCA concentrations and pH (6.2–8.5) in northern Alaskan freshwater lakes (Longo et al., 2016) suggests that Group I Isochrysidales may preferentially thrive in freshwater lakes with high pH. Here, we systematically study LCA distributions, haptophyte-specific 18S rDNA sequences, and concentrations of major ions and trace elements in 18 freshwater volcanic lakes in northeastern China with an extended pH range from 7.17 to 9.99. We find that 11 of the 18 lakes examined contain Group I LCAs and the corresponding DNA sequences of their producers. Our DNA results indicate that the dominant alkenone producer in all 11 lakes is closely related to the Group I Greenland OTU 5 genotype, with the exception of two anthropogenically impacted lakes where small numbers of Group II sequences are found. Statistical analyses indicate that the highest concentrations of Group I LCAs are found in oligotrophic freshwater lakes with pH ranging from ∼7.3 to 8.8. We find that elevated concentrations of certain trace elements may lead to the disappearance of Group I LCAs despite lake water falling within the optimal pH range. Together with previously published Group I LCA data from the temperature calibration in Northern Hemisphere freshwater lakes (Longo et al., 2018), we find, for the first time, that Group I R3b (R3b = C37:3b/(C38:3bEt + C37:3b)) values are most sensitive to winter temperature changes when mean winter temperature is higher than ∼−20°C. Our results suggest that the freshwater volcanic lakes in northeastern China are highly valuable targets for paleotemperature reconstructions using Group I LCAs.

Release of Nutrients and Trace Elements from Wood-, Agricultural Residue- and Manure-Based Biochars

Biochar has been used in many applications as a remediation material, but less attention has been paid to the potential release of various soluble components that may alter the effectiveness of the remediation process. Here, we report the release of nutrients, trace elements, anions and cations from 36 types of biochars. A batch-style experiment was performed by mixing biochar and water at a mass ratio of 1:75. Elevated concentrations of these components were observed in the majority of the solutions mixed with the biochars. No significant differences were observed between low-temperature (low-T, 300 °C) and high-temperature (high-T, 600 °C) biochars in terms of NO3−, Cl−, Na+, Ca2+, Fe, Cu, PO4-P, NH3-N, and K+ concentrations (P < 0.05). Agricultural residue biochars released significantly less Cl−, Na+, Mn, Ca2+, and K+ than manure-based biochars. The observation of nutrients and metal ions in solution was supported by the results of scanning electron microscope/energy-dispersive X-ray (SEM/EDX) analysis. The release of elevated concentrations of anions, cations, trace elements, and nutrients may affect receiving water bodies after the application of biochar.

Genesis of the giant Shizhuyuan W–Sn–Mo–Bi–Pb–Zn polymetallic deposit, South China: Constraints from zircon geochronology and geochemistry in skarns

The giant Shizhuyuan W–Sn–Mo–Bi–Pb–Zn polymetallic skarn-type deposit, which lies in the world-famous Nanling W–Sn metallogenic belt, has a close affinity with the Qianlishan granite complex. Previous studies focused on the Qianlishan granitoids rather than relevant skarns, where the evolutionary processes of skarn-forming fluids, mineralized fluids and sources of metals are debated. This study carried out systematic EPMA and LA-ICPMS zircon U–Pb dating, major- and trace-element and Lu–Hf isotopic analyses for three types of skarns: ore-free, greisen stockwork and sulfide-bearing skarns at Shizhuyuan. The whole skarn zircons were classified into six age clusters (125–187 Ma, ∼235 Ma, 345–509 Ma, 677–772 Ma 811–921 Ma and >1000 Ma) and three genetic types (detrital, magmatic and hydrothermally-altered). Among them, the majority of the skarn zircons are of detrital origin (345 to 2225 Ma, peaking at ∼410 Ma, ∼710 Ma and ∼905 Ma) and showing a wide range of Th/U ratios (0.05–7.09). They share similar characteristics of zircons hosted by Devonian strata in South China, suggesting the inheritance from wall-rock. The magmatic zircons in skarns can be further subdivided into two clusters: Triassic (∼235 Ma) and Jurassic (∼150 Ma), which are derived from the corresponding granite. Ore-free skarn contains only detrital zircons that have experienced the weakest alteration, indicating the minor participation of granitic fluid. The greisen stockwork skarn consists of both detrital zircons and Jurassic magmatic–hydrothermal zircons, implying that granitic and stratigraphic materials may both contribute greatly to the W–Sn polymetallic mineralization. Sulfide-bearing skarn includes abundant detrital zircon, a few of Triassic zircons but no Jurassic zircons, indicating that the latest sulfide mineralization was dominated by sediments rather than granitic rocks. The two mineralized skarn zircons display elevated concentrations of most trace elements (e.g., U, REE, Ti, Y, P, Nb and Ta) coupled with decreased Si and Zr, which reflects strong fluid-rock reaction. The lowest ratios of Ce/Ce* (1.22–89.78, mean = 24.13) in greisen stockwork skarn zircons reveal the most reducing environment for the main W–Sn mineralizing event. Jurassic zircons are homogeneous in 176Hf/177Hf (0.282352–0.282454) and εHf (t) (−11.58 to −7.27), in well accord with local granitic rocks. Triassic zircons have variable εHf (t) (−9.5 to −1.6) values, suggesting more mantle input of precursor pluton before the Jurassic main mineralization event. Based on the zircon geochronology in skarns, we speculate that concealed Triassic magmatism exists in the deep Shizhuyuan area. Consequently, a three-stage ore-forming model was established for the giant Shizhuyuan deposit. This study further illustrates that zircon can be used as an important indicator for ore genesis in complex metallogenic systems.

Control of the mobilization of arsenic and other natural pollutants in groundwater by calcium carbonate concretions in the Pampean Aquifer, southeast of the Buenos Aires province, Argentina

The water supply for human consumption in the Chaco-Pampean region in Argentina is restricted by the low quality of groundwater due to elevated concentrations of arsenic and other trace elements. Previous studies indicated a complex concurrence of factors and processes that are believed responsible to control the distribution of arsenic in groundwater. For a better understanding of the origin of trace elements in the Pampean aquifer, flow-through experiments with loess and calcrete samples representative of the sediments that constitute the aquifer were carried out in continuous flow reactors. The aqueous solutions were collected and the concentrations of SiO2(aq), Ca2+, SO42−, Na+, Cl−, F− and trace elements (Ba, Sr, V, and As) were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), high performance liquid chromatography (HPLC) and capillary electrophoresis. The experiments showed differences in the release rate of elements to the solution according to the type of sediment. The highest concentrations of V, Ba, and As were measured in experiments conducted with loess, and these elements were released quickly to the solution in the first minute of the test. In the case of loess, V and As are suggested to be adsorbed on the solid particles surface. Conversely, the experiments conducted with calcrete showed a lower but continuous release of those elements. This last result may indicate that the trace elements were coprecipitated in the calcite. In addition, it was demonstrated that F did not come from the dissolution of minerals such as fluorapatite, but both desorption from solid surface and dissolution from calcite minerals account for the release of F. This study support that both dissolution and adsorption-desorption processes can control the mobility of trace elements, with an emphasis on the role of calcrete in the retention and the mobilization of trace elements in the Pampean aquifer.

A field assessment of bauxite residue rehabilitation strategies

Bauxite residue, the by-product of the alumina industry, is mainly stored in land-based bauxite residue disposal areas (BRDAs). Environmental concern has been raised due to the large volumes in stockpile, the high alkalinity of the material, as well as the presence of elevated concentrations of trace elements. If not adequately managed, BRDAs can act as a source of pollution. In order to minimize the environmental risk, revegetation is implemented to stabilize the residue against water and wind erosion. Currently, two main approaches are used: the use of amendments or the installation of a capping layer. However, few studies evaluating the long-term success and self-sustainability of the rehabilitation programs have been published.A series of field-established rehabilitation strategies reflecting both direct revegetation and revegetation on capping layer were assessed in terms of both soil and plant quality. Soil physico-chemical properties, including pseudo-total and plant-available fractions of nutrients and trace elements, were determined over a summer and winter seasons and aerial portions of vegetation were analysed for nutrients and trace elements.Failure to adequately lower alkalinity remains the major constraint to long-term rehabilitation success of bauxite residue. This is evidenced from poor soil properties in unamended residue and in residue capped with a shallow soil layer, as well from vegetation displaying excessive concentrations of certain elements. Certain elements exceeded typical ranges for non-contaminated soils (i.e. Cr, Fe, Na, Ni and V), with some showing excessive plant-available fractions (i.e. of Al, As, Cr, Hg and V). Vegetation analysis found excessive uptake of some elements (i.e. of Al, Na, Fe, Cr and V). Future attempts for bauxite residue rehabilitation should include both gypsum and organic amendments, while a capping layer may only be effective if either a deep layer (>1 m) is installed or if the underlying residue is sufficiently treated prior to capping.

Chemostratigraphic resolution of widespread reducing conditions in the southwest Pacific Ocean during the Late Paleocene

Paleogene strata throughout much of the southwest Pacific is comprised of thick successions of fine-grained siliceous to calcareous sediments. However, during the Late Paleocene the south Pacific experienced widespread deposition of organic-rich and δ13Corg-enriched sediments that are recorded in the Waipawa Formation and the correlative Waipawa Organofacies. The mechanisms responsible for the elevated input and preservation of organic matter are still poorly understood. Using a multi-proxy chemostratigraphic approach we assess paleoceanographic conditions, including paleo-redox states and paleo-productivity of the Waipawa Formation. Eight key sections from the East Coast Basin, New Zealand were sampled and analysed for multi-element geochemistry and bulk pyrolysis. Sedimentological, stratigraphic and chemostratigraphic evidence indicates the south Pacific underwent an abrupt regression event during the Late Paleocene resulting in on-shelf erosion and/or bypassing of continental sourced sediments from the shelf into deeper waters. The change in sediment delivery further increased nutrients and terrestrial organic matter loading to the site of deposition. Coeval excursions in Ti/Zr and Rb/Sr indicate a shift to an aluminosilicate-dominated sediment supply, resulting in a modest increase in marine productivity that cannot account for the anomalous organic matter enrichment. Changes in the hydrogen index show a transition from terrestrial to mixed terrestrial–marine organic matter occurred during the Late Paleocene, in which high concentration of Type II-III kerogens were buried and preserved in association with enhanced water column reducing conditions in deep marine settings. Elevated concentrations of redox-sensitive trace elements (e.g. U, Mo, Fe, S) are consistent with alternating phases of dysoxic to oxic conditions suggesting an expansion of an oxygen minimum zone, enhancing preservation and delivery of organic matter to the seafloor, leading to the subsequent burial and preservation of organic matter within anoxic sediments. These new data provide insight into the depositional conditions and the petroleum potential of prospective source rocks in this basin using an integrated organic and inorganic geochemical approach to refine our knowledge of the depositional environment and paleoceanographic changes in shelfal to bathyal marine sediments of the Late Paleocene.

Geochemistry of Palaeogene coals from the Fuqiang Mine, Hunchun Coalfield, northeastern China: Composition, provenance, and relation to the adjacent polymetallic deposits

This paper describes the geochemistry of the two Palaeogene coal seams (FQ-23 and FQ-26) from the Fuqiang mine, Hunchun Coalfield, Jilin Province, northeastern China. The samples investigated consist of coal, parting, and roof and floor strata. The two Fuqiang coals are lignite/subbituminous rank and have low sulfur contents (0.13% and 0.16% on average, respectively). In comparison with the average values for common global low-rank coals, the Fuqiang coals are richer in W, Cs, Sb, Pb, Li, V, Ga, and Zr.The terrigenous components in the Fuqiang coals were derived from the Mesozoic (mostly Lower Cretaceous) and Paleozoic igneous and metamorphic rocks, which are abundant in areas surrounding the Hunchun coal basin. The elevated concentrations of trace elements are attributed to two processes: (1) Contribution of clastic materials derived from mineralized Paleozoic rocks, which also host economical ore deposits of these elements; and (2) Mobilisation and redeposition of these elements by acidic waters, which circulated within the coal basin. The latter is evidenced by enrichment in medium rare earth elements, distinct positive Gd anomalies, and high concentrations of boron in the coals. The overall similarity of the geochemical signatures of the Fuqiang coals and the adjacent Au, Cu and W deposits hosted by the Paleozoic igneous and metamorphic rocks underlying and bordering the Hunchun Basin, indicate that they are genetically linked.

Ecotoxicological risk of trace element mobility in coastal semiartificial depositional areas near the mouth of the river Rhine, the Netherlands.

Artificial sand replenishments are globally used as innovative coastal protection measures. In these replenishments elevated porewater concentrations of trace elements are found. The present study investigated possible ecotoxicological risks at 2 intertidal depositional sites, the Sand Engine as a recent innovative Dutch coastal management project and a semiartificial tidal flat. Using the sediment quality triad approach, we considered 3 major lines of evidence: geochemical characterization, toxicity characterization using bioassays with the estuarine amphipod Corophium volutator, and ecological field survey. In both depositional areas C. volutator is at risk: moderate (Sand Engine) and low (tidal flat). For tidal flat, the bioavailability of trace elements differs between the field site and the laboratory. Contamination from arsenic and copper is present, but the low survival rate of C. volutator from the bioassay suggests the presence of additional contaminations. The highly morphological dynamic environment of Sand Engine creates a less favorable habitat for C. volutator, where local spots with stagnant water can temporarily create hypoxic conditions and sulfate becomes reduced. The dynamic system mobilizes especially arsenic, triggering adverse ecotoxic effects at low original sediment concentrations. To conclude, the sediment quality triad approach shows that a semiartificial tidal flat is preferred over a highly dynamic coastal management project like the Sand Engine. The Sand Engine concept does not provide suitable conditions for macrobenthos species like C. volutator; therefore, limiting the nature development goal set together with the coastal protection goal. Assessing each line of evidence from the approach together with additional measurements established more precise and realistic conclusions, showing that evaluating the contributions of this method is necessary to understand the causes of risk in a site-specific manner. Environ Toxicol Chem 2018;37:2933-2946. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Residual pollution and vegetation distribution in amended soils 20 years after a pyrite mine tailings spill (Aznalcóllar, Spain)

The present work assesses the residual pollution in the Guadiamar Green Corridor (SW, Spain) after a long-term aging process (18 years) since the accident of the Aznalcóllar pyrite mine. We have focused on the study of trace elements (Cu, Zn, Cd, As and Pb) in soils, their fractionation and the transference to the surrounding vegetation. The residual polluted areas are characterized by scattered plots with absence of vegetation, presenting high concentrations of trace elements, acidic pH and low organic carbon content. Surrounding these polluted plots, two vegetation gradient belts are clearly identified by changes in plant cover and richness. The inhibition of plant growth in the bare soils is related to the highest mobility of soluble and exchangeable Cu, Zn and Cd forms, which significantly decrease with the distance to the polluted plots.Plant richness and cover show differences between belts; bioaccumulation of trace elements in plants also differs, with a preferential accumulation in roots. Despite the low bioavailability of As and Pb in soils, bioaccumulation factors in plants for these elements are significantly higher in belt 1 in relation to belt 2. High Cu and Cd potential toxic concentrations in aerial parts of vegetation are found, posing a risk for livestock and a potential entrance to the food-chain. On the other hand, Lamarckia aurea (L.) Moench (in belt1) and Trifolium campestre Schreb. (in belt2) were the most dominant species in severely polluted soils. Elevated concentrations of trace elements in the vegetation growing in the area indicate plant adaptation mechanisms to live in these severely polluted soils, which can be used as a good bioindicator of pollution in similar polluted areas.

Arsenic Concentration in the Surface Water of a Former Mining Area: The La Junta Creek, Baja California Sur, Mexico.

The mining activity in the San Antonio-El Triunfo district, located in a mountainous region at 60 km southeast of La Paz, occured for more than 250 years and left behind severe contamination of soils and riverbed sediments which led to elevated concentrations of arsenic and other trace elements in the surface- and groundwater of the region. Although the main mining activity ended around 1911, contamination is still beeing distributed, especially from left behind tailings and mine waste piles. The contamination levels in the groundwater have been reported in several studies, but there is little information available on the surface water quality, and especially the temporal variation. In this study, we analyzed the surface water of the La Junta creek, in the southern part of the San Antonio-El Triunfo mining district. The working hypothesis was that by means of a spatial analysis of surface water and shallow groundwater, in combination with the temporal observation of the concentrations in runoff water, the effects of different sources of arsenic (natural geogene anomalies, due to historic mining activity, and hydrothermal related impact) in the La Junta creek can be recognized. This present study revealed that historic mining activity caused a mojor impact of arsenic but less contamination was observed than in the northern part of the district and elevated arsenic concentrations in stream water generally occurred during times of low streamflow.

Zircon trace element and isotopic (Sr, Nd, Hf, Pb) effects of assimilation-fractional crystallization of pegmatite magma: A case study of the Guangshigou biotite pegmatites from the North Qinling Orogen, central China

Evidence for open-system magmatic processes related to wallrock assimilation accompanied by fractional crystallization (AFC) is present in the Guangshigou biotite pegmatites, North Qinling Orogen. The biotite pegmatite-gneiss contacts generally coincide with the greatest enrichment of U and Th. Zircon UPb dating constrains the crystallization ages of the biotite pegmatite (rim zone-415±2.6Ma; internal zone-413.5±2.5Ma), in line with a pyrite PbPb isochron age (413±22Ma). Metamict areas in zircon show generally elevated concentrations of trace elements and expulsion of radioactive Pb. Internal zone samples, representing uncontaminated magma, have negative to positive zircon (~413Ma) εHf(t) (−1.53−+3.24), low εNd(t) values (−2.4), and old Hf and Nd model ages (tDM2=1.5–1.19Ga, T2DM=1.35Ga, respectively), indicating a dominantly recycled Mesoproterozoic lower crustal material with involvement of some juvenile materials in the source region. The magmatic oxygen fugacity (fO2) and crystallization temperatures ranges from −24.81 to −13.34 of log fO2 and 570°C to 793°C, respectively. Compared to the internal zone, pegmatite rim samples display a variable and lower εNd(t) values (−3.9 to −2.8) and T2DM (1.47–1.37Ga), but similar Hf isotopic compositions, favouring a three-component isotopic mixing model (recycled Mesoproterozoic lower crust materials, juvenile materials, and host gneiss). Pronounced variations of Ti, Y, U, Th, Hf, and REE concentrations in zircon from grain to grain in individual samples and from area to area within individual grains suggest a fluctuating crystallization environment in hybridized magma from which the rim-hosted zircons crystallized. Variable and high radiogenic Pb ratios of pyrites forming in the hybridized magma were inherited from the matrix. Zircons from both zones exhibit similar Hf isotope patterns, indicating the rim-hosted zircons crystallized during the early stage of hybridization of magma. However, the heterogeneous Nd isotopic composition in individual pegmatites imply an incorporation of wallrock-derived melt with less radiogenic Nd.

Partitioning of hazardous elements during preparation of high‑uranium coal from Rongyang, Guizhou, China

The Late Permian coal from Rongyang Mine in southwestern China is characterized by high content of sulfur (5.44%) and elevated concentrations of trace elements U (70.5μg/g), V (283μg/g), Cr (63.2μg/g), Co (12.8μg/g), Cu (59.5μg/g), Se (5.28μg/g), and Mo (87.5μg/g). Because of their potential adverse effects on human health and environments, it is important to understand the pathways of these elements during preparation. This study focuses on the distribution of hazardous elements in the size- and density-fractionated samples of this coal. The results indicated that: (1) The minerals in the Rongyang coals are mainly composed of quartz, pyrite, marcasite, calcite, anatase, illite, and kaolinite, along with traces of coquimbite, bassanite, roemerite, gypsum, dolomite, rutile, and siderite. Most of the minerals can be effectively liberated from cleaned coal by gravity separation. (2) Elements U, V, Cr, Co, Cu, Se, and Mo with a high content in the Rongyang coal are derived from exfiltrational hydrothermal fluids during syngenetic or early diagenetic stages, and are associated with inorganic components such as clay minerals, pyrite, anatase, and guadarramite as well as organic components. Selenium mainly occurs in pyrite (particularly epigenetic pyrite) in the coal. (3) Uranium is the easiest to remove through gravity separation (the removability is 68.33%) and has lowest concentration (10.5μg/g) in the 3–6mm size fractions compared to the others size fractions. It was also found that uranium cannot be removed through gravity separation completely, due to its association with the organic components and fine-grained minerals. The U concentration in the cleaned coal is still much higher than the average value for world hard coals. The ash from the cleaned coal with particle size of 6–13mm and <0.5mm could be potentially used for industrial extraction of uranium. (4) The minerals that are epigenetic in origin are easily liberated during coal cleaning. Therefore, hazardous elements Co, Ni, Cu, As, Se, Cd, Sb, Hg, Tl, and Pb that are associated with epigenetic pyrite are thus relatively easy to remove, whereas elements V, Cr, and Mo that are evenly distributed in inorganic and organic components, are more difficult to be removed.

Chemical water quality gradients in the Mongolian sub-catchments of the Selenga River basin.

Even though the Selenga is the main tributary to Lake Baikal in Russia, the largest part of the Selenga River basin is located in Mongolia. It covers a region that is highly diverse, ranging from almost virgin mountain zones to densely urbanized areas and mining zones. These contrasts have a strong impact on rivers and their ecosystems. Based on two sampling campaigns (summer 2014, spring 2015), we investigated the longitudinal water quality pattern along the Selenga and its tributaries in Mongolia. While headwater regions typically had a very good water quality status, wastewater from urban areas and impacts from mining were found to be main pollution sources in the tributaries. The highest nutrient concentrations in the catchment were found in Tuul River, and severely elevated concentrations of trace elements (As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Zn), nutrients (NH4+, NO2-, NO3-, PO43-), and selected major ions (SO42-) were found in main tributaries of Selenga River. Moreover, trace element concentrations during spring 2015 (a time when many mines had not yet started operation) were markedly lower than in summer 2014, indicating that the additional metal loads measured in summer 2014 were related to mining activities. Nevertheless, all taken water samples in 2014 and 2015 from the main channel of the Mongolian Selenga River complied with the Mongolian standard (MNS 1998) for the investigated parameters.

Whole Blood Characterization in School Teachers with Reference to Chalk Sticks

It is known that usage of chalk causes dust and exposure to chalk dust can cause health hazards in teachers. But the level of exposure to chalk dust in teachers were not known so far. Hence, present study aimed to investigate the level of exposure to chalk dust in teachers by studying the whole blood concentrations of trace elements (Al, Cr, Mn, Fe, Co, Ni, Si, Pb) that are associated with chalk. ICPMS method was adopted to conduct the trace element concentration in whole blood and due to lack of reference standards, the recovery percentages were analyzed. From the results, it is identified that except Si all the elements are noticed beyond the normal blood limits in teachers. For silicon, there is no normal blood limit. The relation between the trace elemental concentration and socio demographic variables like gender, age, Years of service was also studied. The age and gender did not show significant difference with the trace element concentration. The years of service revealed a positive association with trace element concentrations. The elements like Si (70847 μg/l), Iron (19499 μg/l), Al (1389.9 μg/l) were noticed with elevated concentrations in teachers. The same elements were reported with higher concentrations in past studies that are conducted on trace elements concentration of chalk. Hence, it is proved that the chalk is the prime reason for the elevated concentrations of trace elements in blood and it also concluded that usage of chalk causes health hazards in teachers.

Trace elements in the sea surface microlayer: rapid responses to changes in aerosol deposition

Natural and anthropogenic aerosols are a significant source of trace elements to oligotrophic ocean surface waters, where they provide episodic pulses of limiting micronutrients for the microbial community. However, little is known about the fate of trace elements at the air-sea interface, i.e. the sea surface microlayer. In this study, samples of aerosols, sea surface microlayer, and underlying water column were collected in the Florida Keys during a dusty season (July 2014) and non-dusty season (May 2015) and analyzed for the dissolved and particulate elements Al, Fe, Ni, Cu, Zn, and Pb. Microlayer samples were collected using a cylinder of ultra-pure SiO2 (quartz glass), a novel adaptation of the glass plate technique. A significant dust deposition event occurred during the 2014 sampling period which resulted in elevated concentrations of trace elements in the microlayer. Residence times in the microlayer from this event ranged from 12 to 94 minutes for dissolved trace elements and from 1.3 to 3.4 minutes for particulate trace elements. These residence times are potentially long enough for the atmospherically derived trace elements to undergo chemical and biological alterations within the microlayer. Characterizing the trace element distributions within the three regimes is an important step towards our overall goals of understanding the rates and mechanisms of the solubilization of trace elements following aeolian dust deposition and how this might affect microorganisms in surface waters.

Geochemistry and petrogenesis of Mesoproterozoic A-type granitoids from the Danish island of Bornholm, southern Fennoscandia

Granitoids and gneisses from the Danish island of Bornholm have been investigated using whole rock geochemistry, Sr and Nd isotope geochemistry and Hf isotopes in zircon. Recent U–Pb dating shows that the rocks were formed during a short time interval at 1.45 to 1.46Ga, penecontemporaneous with ongoing deformation. The strong similarity in geochemical signatures indicate that they all belong to a single igneous suite composed of alkali-calcic biotite–hornblende quartz monzonites to more evolved biotite granites, albeit with an apparent gap in SiO2 content at around 70wt%, dividing the suite into an intermediate and a felsic part. These dominantly metaluminous rocks are strongly ferroan and potassic, and with highly elevated concentrations of many trace elements, traits that are typical for A-type granitoids. The presence of magnetite and titanite indicates relatively oxidized compositions, and Nb/Y ratios designate them to the A2 subtype. Initial whole rock εNd values range between +1 and -2 (with one outlier at +4), and initial zircon εHf values between +3 and -4. These values may be explained by melting of relatively juvenile crust similar to that forming the Transscandinavian Igneous Belt alone, but the spread in Hf and Nd isotope compositions to values overlapping with the Svecofennian mantle at 1.45Ga suggests involvement of a mantle-derived component. This indicates the magmatism was associated with juvenile crustal growth. There are no systematic differences in isotope or trace element characteristics between the orthogneisses and the less deformed granitoids, suggesting similar origins for both rock types, and no systematic changes in isotopic composition with SiO2 concentration.Trace element compositions indicate a within-plate setting, similar to other 1.45Ga granites in southwest Fennoscandia, in spite of the close relation between magmatism and deformation on Bornholm. We therefore suggest intracratonic A-type magmatism within an active continental shear zone as a tentative model for the Mesoproterozoic magmatism on Bornholm. However, a close relationship to the nearby Hallandian tectono-magmatic activity in southern Sweden, attributed to continental margin orogenic processes, is also evident. Intermediate magmas presumably formed by ponding of enriched mantle-derived basic magma at the crust-mantle boundary or within the lower crust, causing extensive partial melting and assimilation of mafic to intermediate crustal rocks related to the Transcandinavian Igneous Belt. The magmas then evolved to granitic compositions by removal of an assemblage similar to that seen petrographically, i.e. plagioclase, amphibole, magnetite, titanite, and late-stage K-feldspar.

Mineralogical and geochemical compositions of Late Permian coals and host rocks from the Guxu Coalfield, Sichuan Province, China, with emphasis on enrichment of rare metals

This paper reports the geochemical and mineralogical compositions of the Late Permian No. 25 Coal (semi-anthracite) and its host rocks (roof and floor strata) from the Guxu (Gulin–Xuyong) Coalfield, Sichuan Province, China. The coal is characterized by medium-sulfur content (average 2.73%) and has an average ash yield of 20.95%. In contrast to other Late Permian coals from southwestern China that are enriched in Sc, V, Cr, Co, Ni, and Cu, the No. 25 coal does not contain an abundance of these transition elements but is rich in lithophile elements Be, Y, Nb, Zr, Hf, and U. The elevated concentrations of trace elements in the No. 25 Coal were probably derived from the felsic–intermediate rocks at the top of the Emeishan basalt sequence, rather than from the Emeishan mafic basalts.The floor strata of the No. 25 Coal can be divided into two sub-sections. The upper sub-section of the sequence immediately below the No. 25 Coal consists of material with a felsic–intermediate composition probably derived from terrigenous sources and the lower sub-section is composed of mafic tuff. The terrigenous mineral matter in the No. 25 coal appears to have the same sediment-source region as the upper sub-section of the floor strata, based on their similar geochemical compositions. The roof strata of the No. 25 Coal are more quartzose, and were probably derived from a different sediment-source region. The mineral matter in the coal is dominated by kaolinite and, to a lesser extent, calcite and pyrite; the roof and floor strata each have quite different mineralogy, with kaolinite dominant in the latter and illite, kaolinite and quartz in the former; pyrite contents are variable both in the coal and in the host rocks. The floor strata and the coal have been affected by hydrothermal solutions, leading to the enrichment of rare earth elements and yttrium (REY), Nb, Ta, Zr, Hf, and U. The REY in the coal and floor strata, as well as the Nb, Ta, Zr, Hf, and U in the floor strata, represent potentially economic rare metal resources.

Trace Element Concentrations in Liver of 16 Species of Cetaceans Stranded on Pacific Islands from 1997 through 2013.

The impacts of anthropogenic contaminants on marine ecosystems are a concern worldwide. Anthropogenic activities can enrich trace elements in marine biota to concentrations that may negatively impact organism health. Exposure to elevated concentrations of trace elements is considered a contributing factor in marine mammal population declines. Hawai'i is an increasingly important geographic location for global monitoring, yet trace element concentrations have not been quantified in Hawaiian cetaceans, and there is little trace element data for Pacific cetaceans. This study measured trace elements (Cr, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Hg, and Pb) in liver of 16 species of cetaceans that stranded on U.S. Pacific Islands from 1997 to 2013, using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) (n = 31), and direct mercury analysis atomic absorption spectrometry (DMA-AAS) (n = 43). Concentration ranges (μg/g wet mass fraction) for non-essential trace elements, such as Cd (0.0031-58.93) and Hg (0.0062-1571.75) were much greater than essential trace elements, such as Mn (0.590-17.31) and Zn (14.72-245.38). Differences were found among age classes in Cu, Zn, Hg, and Se concentrations. The highest concentrations of Se, Cd, Sn, Hg, and Pb were found in one adult female false killer whale (Pseudorca crassidens) at concentrations that are known to affect health in marine mammals. The results of this study establish initial trace element concentration ranges for Pacific cetaceans in the Hawaiian Islands region, provide insights into contaminant exposure of these marine mammals, and contribute to a greater understanding of anthropogenic impacts in the Pacific Ocean.

Seasonal and spatial variation of trace elements in multi-size airborne particulate matters of Beijing, China: Mass concentration, enrichment characteristics, source apportionment, chemical speciation and bioavailability

The seasonal and spatial variation characteristics of 19 elements (Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Sb, Se, Zn) in TSP/PM10/PM2.5 samples were investigated, which were collected from April 2011 to January 2012 simultaneously at an urban downtown site, a traffic roadside site, a suburban site, and a rural site in Beijing. The elevated concentrations of several toxic trace elements (As, Cd, Mn, Ni, Pb, etc.) in particles revealed that the contamination of toxic elements in Beijing could not be neglected. Positive matrix factorization method (PMF) was applied for source apportionment of trace elements in PM, and three factors (crust related sources, combustion sources, and traffic and steel industrial related sources) were identified. Furthermore, the chemical speciation and bioavailability of various elements were identified by applying European Community Bureau of Reference (BCR) procedure. Our results showed that eight toxic elements (As, Cd, Cr, Cu, Ni, Pb, Sb and Zn) exhibited higher mobility in PM2.5 than in PM10. Notably, elements of As, Cd, Pb and Zn were presented with higher mobility than the other elements, and these elements were lightly to release into the environment and easily available to human body. Additionally, As, Cd, Pb and Zn also accounted for higher percentages in the bound to mobile fractions at the central urban areas of Beijing. Therefore, special concerns should be paid to these toxic trace elements which had relatively high mobility in fine particles, when planning and implementing the comprehensive air pollution mitigation policies in Beijing.