Average Trace Element Concentrations Research Articles

Effects of Land Uses on Soil Quality of Shwan Sub-basin, Kirkuk Governorate, Northern Iraq

Thirty-two soil samples were collected from the study area in October 2020 for geochemical and pollutants investigation of Shwan Sub-basin soil. All soil samples were analysed for different geochemical analyses. The analysis results revealed that the pH values in soil samples ranged from 7.12 to 7.56 with a mean of 7.327. According to the pH values detected in the soil samples, the soil is classified as neutral soil. The electrical conductivity ranged from 0.92 mmhos/cm to 7.8 mmhos/cm with a mean of 1.53 mmhos/cm. Thus, according to the detected electrical conductivity values, the soil was classified as non-saline to slightly saline. The organic matter ranged from 1.14% to 1.45% with a mean value of 1.326 %, while total organic carbon ranged from 0.66 % to 0.84 % with a mean value of 0.769 % which indicated the soil was characterized by low organic content. The results of the geochemical analysis revealed that the major and minor element mean concentrations were in the order Si> Ca> Al> Fe> Mg > K> Ti> Na> P> Mn> S> Cl> N. The average concentrations of trace elements in soil samples followed the decreasing order Sr > Cr> Ba> Zr> Ni> V> Zn> Ta> Rb> Cu> Nb> Y> Pb> Co> Ga> Mo> As> Th> Br> Sn> I. Furthermore, the comparison between heavy metal concentrations in the soil of the study area and metal concentrations in the world soil limit and Indirect Geochemical Background revealed an increase in metal concentrations of Cr, Ni, Zn, Co, As, Mo and Ta. Multivariate statistical analyses, such as Principal Component Analysis and Agglomerative Hierarchal Cluster Analysis, identified the potential sources of pollutants in the soil. Most metals are from natural sources and some of them are from anthropogenic sources mostly from agricultural activities mainly fertilizers use and the waste of animals breeding on farms. Besides industrial activities such as deposits of pollutants from emissions of petroleum refineries located inside or close to the study area. In addition, building blocks and paint factories.

Geochemical Evidence of Ediacaran Phosphate Nodules in the Volyno-Podillya-Moldavia Basin, Ukraine

The sedimentary basin of Podillya (Volyno-Podillya-Moldavia) is situated in the southwest of the Ukrainian crystalline shield and belongs to the middle part of the Upper Neoproterozoic section of the Moguiliv-Podilska Group. By analyzing the primary oxide, trace, and rare-earth element compositions of the phosphate nodules in the area, this study sought to shed light on the potential precipitation characteristics of the Ediacaran Sea, where phosphate nodules were created. The mean major oxide contents of the nodules were 50.8 wt.% CaO, 34.2 wt.% P2O5, 5.29 wt.% SiO2, 4.77 wt.% LOI, 1.69 wt% Fe2O3, 1.63 wt% Al2O3, and 0.35 wt.% MnO. The average trace element concentrations were 183 ppm Ba, 395 ppm Sr, 13.4 ppm Ni, 32.7 ppm Cr, 62.2 ppm Zn, 764 ppm Y, 16 ppm V, 10.8 ppm As, 75.8 ppm Cu, 84 ppm Pb, 2.1 ppm U, 1.7 ppm Th, and 4.2 ppm Co. The trace element contents were generally low and indicated an assemblage of Cu, Y, As, Cd, and Pb enrichments in comparison to PAAS. The total REE concentrations varied from 1638 ppm to 3602 ppm. The nodules had medium REE (MREE) enrichments and showed similar REE patterns normalized to PAAS. All the nodules had strongly negative Ce, Pr, and Y anomalies and substantially negative Eu anomalies, with four samples being exceptions. These abnormalities suggest that oxic and suboxic sea conditions existed at the time the nodules formed. The extremely high REE concentrations are thought to be the result of REEs being redistributed between the authigenic and detrital phases that were created during the diagenetic equilibration of phosphate with pore water. The genetic hypothesis for phosphate nodule formation states that the nodules were generally formed in oxic and suboxic seawater and were precipitated on slopes in response to a significant upwelling from a deeper basin with abundant organic matter under anoxic/suboxic conditions. The majority of the organic material at the water–sediment interface of the seafloor underwent oxidation before phosphate was released into the pore water of the sediment.

Concentrations of potentially toxic and essential trace elements in marketed rice of Bangladesh: Exposure and health risks

Rice is a major dietary source of essential trace elements required for the human body but also can be an exposure pathway to different potentially toxic trace elements. This study determined various essential and toxic trace elements in rice from Bangladeshi markets and their possible health risks. Concentrations of essential and toxic trace elements in rice varied significantly from location to location. Mean concentrations (mg kg−1 as dry weight) of essential trace elements were found in the following order - Zn>Mn>Cu>Fe>Mo>Se>Co - and were within their maximum allowable limits. The average concentrations (mg kg−1) of toxic trace elements were as follows: As: 0.17, Cr: 0.18, Ni: 0.55 and Pb: 0.18, while 7% and 40% of the rice samples surpassed, respectively, the EU recommended limits of As and Pb. This study revealed that rice could be a primary exposure pathway of toxic elements, leading to either noncarcinogenic or carcinogenic health problems for daily rice consumers. The non-carcinogenic health risk was mainly associated with As which contributed 77% to the hazard index. The carcinogenic risk measured as incremental lifetime cancer risk (ILCR) was high (>10−4) with As, Cr and Ni, while Pb showed a moderate (<10−4) carcinogenic risk to adults. Rice can substantially be contaminated by trace elements other than As with potential human health risks. Consequently, regular monitoring of the marketed rice grain is demanded, backed up by viable mitigation strategies for reducing toxic elements uptake by rice grains.

Geochemical Approach to Determine the Possible Precipitation Parameters of the Coniacian–Santonian Mazıdağı Phosphates, Mardin, Turkey

The Tethyan phosphates were formed during the Upper Cretaceous and Eocene interval as a result of the collision of the African–Arabian and Eurasian plates and the closing of the Neo-Tethys Ocean. This study aimed to reveal the possible precipitation parameters of these phosphates by examining the main oxide, trace element, and rare earth element contents of the phosphates in the study region. The mean major oxide concentrations of the phosphates were found to be 51.6 wt.% CaO, 21.2 wt.% P2O5, 8.03 wt.% SiO2, 18.1 wt.% CO2, 0.51 wt.% K2O, 0.12 wt.% Fe2O3, 0.05 wt.% Al2O3, 0.18 wt.% MgO, and 0.02 wt.% MnO. The average trace element concentrations were 79 ppm Ba, 1087 ppm Sr, 0.23 ppm Rb, 14.7 ppm Ni, 108 ppm Cr, 262 ppm Zn, 27 ppm Cd, 21.6 ppm Y, 58 ppm V, 6.43 ppm As, 30.3 ppm Cu, 1.36 ppm Pb, 6.32 ppm Zr, 39 ppm U, 0.21 ppm Th, and 1.33 ppm Co. The average trace element contents were 1742 ppm, with this indicating an enrichment assemblage of Sr, Cd, As, and Zn in comparison to PAAS (The Post-Archean Australian Shale). The total REE concentrations in the Mazıdağı phosphates varied from 3.30 to 43.1 ppm, with a mean of 22.1 ppm recorded. All phosphates showed heavy REE (HREE) enrichments and had similar REE patterns to PAAS (The Post-Archean Australian Shale). All samples had strongly negative Ce and positive Eu, Pr, and Y anomalies. These anomalies indicate the existence of oxic and suboxic marine conditions during the formation of the phosphates. According to the proposed genetic model, the phosphates mostly formed in the oxic and suboxic zones of the Tethys Ocean and were precipitated on slopes that depended on strong upwelling from an organic-rich basin in anoxic/suboxic conditions from deeper seawater. The Pb isotope data obtained also indicate the existence of a deep-sea hydrothermal contribution to this phosphate formation.

Spatiotemporal variations of total and dissolved trace elements and their distributions amongst major colloidal forms along and across the lower Athabasca River

With a wide variety of natural and potential anthropogenic inputs, the Athabasca River (AR) has been the focus of recent attention. In addition to natural inputs of trace elements (TEs) from tributaries, industrial activities such as mining and upgrading of bitumen have been viewed as additional, potentially important anthropogenic sources, but evidence is limited. To quantify the spatiotemporal variations of TE concentrations and their forms, water samples were gathered along a 125-km stretch of the river from upstream to downstream of the industrial region, and at three points across the river, along five transects perpendicular to the flow. The samples were collected in the autumn of 2017 and the spring of 2018, using novel, metal-free sampling methods. The concentrations of total (i.e. acid-extractable), and dissolved (i.e., < 0.45 µm) TEs were measured to compare with water quality guidelines, and their size-based distribution amongst major colloidal forms was determined to better assess their biological significance. The results quantify spatiotemporal variation in total and dissolved concentrations of TEs along and across the AR. In both seasons the majority of TEs occurred in the particulate fraction. None of the TEs were significantly enriched in the particulate fraction, relative to crustal abundance. The average concentrations of TEs were below the CCME surface water quality guidelines. The PCA analysis identifies tributary contributions of total and dissolved TEs to the AR.

Trace and major elements in surface snow and fresh water bodies of the Marguerite Bay Islands, Antarctic Peninsula

The results of major and trace elements investigation in snow and fresh water on Dismal and Horseshoe Islands, Marguerite Bay, Antarctic Peninsula are presented. Samples of newly fallen snow, old snow, as well as water from lakes, ponds and streams were collected during the 4th Turkish Antarctic Expedition in February-early March 2020. Determination of Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Na, Mg, Mn, Mo, Ni, Pb, Sb, Se, Th, Tl, U, V and Zn content was carried out using the ICP-MS method. Totally 39 samples were analyzed.It was established that, variability and average concentrations of major and trace elements are significantly higher in newly fallen snow compared to old snow. The lowest concentrations of major and a number of trace elements (Fe, Cr, Se, Ba, As and Tl) were recorded in samples of old snow, and the highest - in water of streams. All types of samples have the highest Na concentrations, that confirms sea aerosols as the source of their input.High enrichment factors EFc (>100) for Zn, Cd, Se and Sb (especially in newly fallen snow) indicate possible anthropogenic impact connected with long-range air mass transfer.

Composition and sources of particulate matter in the Beijing-Tianjin-Hebei region and its surrounding areas during the heating season

This paper aimed to analyze the composition and pollution sources of particulate matter (PM) in the Beijing-Tianjin-Hebei region and its surrounding areas (henceforth the BTH region) during the heating season to support the mitigation and control of regional air pollution. Manual monitoring data from the China National Environmental Monitoring Network for Atmospheric PM in the BTH region were collected and analyzed during the 2016 and 2018 heating seasons. The positive definite matrix factor analysis (PMF) model was used to analyze the PM sources in BTH cities during the heating season. The main PM components were organic matter (OM), nitrate (NO3−), sulfate (SO42−) and ammonium salt (NH4+). Direct emission sources have decreased since 2016, indicating the effectiveness of governmental controls on these sources; however, secondary pollution showed an increasing trend, suggesting control measures should be strengthened. Daily regional average concentrations of OM, SO42−, NH4+, elemental carbon (EC), chloride (Cl−) and trace elements all showed similar trends. When air quality worsened, the concentrations of the main PM components increased, but trends of change varied among components. In 2018, concentrations of OM and chloride were highest in the Taihang Mountains, and NO3 concentrations were highest in Anyang, Hebi, Jiaozuo and Xinxiang. The SO42− concentration was highest in the southern section of the Taihang Mountains. The NH4+ and EC concentrations were generally highest in the central and southern regions. The concentration of crustal substances was highest in some cities in the north and central parts of the BTH region. In the 2018 heating season, the pollution level of five transmission channels showed an increasing trend in the Northwest, Southeast, Yanshan, South and Taihang Mountain channels. These findings provide a scientific basis for the continued management of atmospheric PM pollution.

Trace metal accumulation in agricultural soils from mineral phosphate fertiliser applications in European long‐term field trials

AbstractMineral phosphate (P) fertilisers are the main suspected sources of uranium (U) and cadmium (Cd) input to agricultural soils. This study was set up to survey the general long‐term impact of P fertilisers on concentrations of Cd, U and other trace metals in European soils. A total of 218 soil samples was collected from 15 long‐term (3–78 years, median 18 years) P trials at 11 locations with a pairwise comparison of topsoil composition between the fertilised and corresponding unfertilised soils. Aqua regia soil extraction detected the effects of fertilisation more sensitively than the HF (real total) soil extraction. Statistically significant differences in aqua regia soluble metals due to fertiliser application were detected more frequently for U (10 of 15 trials) than for Cd (4 of 15 trials). The concentrations of U and Cd in soil linearly increased with cumulative applied P across all soils and sites; a total addition of 1 ton P ha−1 increased the mean topsoil (23 cm depth) concentrations by 0.11 mg U kg−1 soil (0.09–0.12 mg U kg−1, 95% CI) and 0.03 (0.02–0.04) mg Cd kg−1 soil. These results correspond with mass balance predictions (1 ton P ha−1; +0.15 mg U kg−1 soil and +0.02 mg Cd kg−1 soil) based on previously determined average trace element concentrations in European fertilisers. Data thus suggests that, on average among trials, losses of Cd from soil are undetectable. In contrast, about 30% of the theoretical U input from fertilisers is lost in the same trials. This study provides data to better evaluate the modelled trace metal accumulations in soil and to evaluate the prevailing metal limits in mineral fertilisers.Highlights U and Cd accumulation in agricultural soils correlates with cumulative mineral P‐fertiliser dose. Accumulation of fertiliser‐derived U is more often detectable compared to Cd. Due to its accumulation potential, U accumulation should be monitored. Aqua regia soluble concentrations better detect metal accumulation in soil than real total concentrations.

Changes of macromineral and trace element concentration in the blood of ewes during lactation period

The aim of the present research was to determine the changes in macromineral and trace element concentrations in ewes’ blood during the lactation period. Thirty-six Travnik pramenka ewes at the average age of 3–5 years were included in research and they were evaluated at three stages of lactation: early stage (40 ± 5 days of lactation), medium stage (80 ± 5 days of lactation) and late stage (120 ± 5 days of lactation). In ewes’ blood concentrations of macroelements (Ca, P, K, Na, Mg) and trace elements (Fe, Cu, Zn, Mo, Co, Se, Cd, As) were determined. The average concentrations of macroelements and trace elements in the blood of ewes during lactation were mostly within the reference values. Se concentrations in blood were close to the deficient ones, while concentrations of Cd and As were negligible. Concentration of Ca in blood was the lowest in the early lactation stage, higher in the late stage, and the highest in the medium stage (88.25 mg/l, 96.43 mg/l and 103.43 mg/l, respectively). A significant increase in the concentrations of Mg, Co and Cd and a significant decrease in the concentrations of Na, Fe, Cu, Zn, Mo and Se were found in blood with lactation progress. Significant correlations between the studied parameters were found, especially between macroelements (Ca : K, P : Na, K : Na, K : Mg). Positive correlations were found between some macroelements and trace elements (Ca : Co, Ca : Cd, K : Co, Na : Zn, Na : Se) and between trace elements (Fe : Cu, Cu : Zn, Cu : Mo, Cu : Se, Zn : Se, Mo : Se and Co : As). Negative correlations were found between Ca and Cu, Ca and Mo, P and Cd, K and Cu. Obtained results may help in monitoring the nutritional status and health of ewes during the lactation period, providing a clearer idea related to the supply of macrominerals and trace elements to ewes. Besides, results indicated that the environment of the farming area was not polluted with toxic elements.

Trace Elements in Mollusks, Crustaceans and Fish Commonly Consumed by the Catfish &amp;lt;i&amp;gt;Chrysichthys nigrodigitatus&amp;lt;/i&amp;gt; Lac&amp;#233;p&amp;#232;de, 1803 from the Lake Togo-Lagoon of An&amp;#233;ho Hydrosystem (Southern Togo)

The omnivorous fish species, C. nigrodigitatus feeds mainly on benthic organisms and may therefore consume contaminated food throughout its food web. This can lead to the bioaccumulation of contaminants such as trace elements in their tissues. However, fish consumption is a major pathway of human exposure to contaminants which may cause public health problems. The aim of the present study is to assess trace elements contamination in some species from the food web of C. nigrodigitatus. For this, 10 main food items of the silver catfish were collected at two sites from February to July 2017 and analyzed using an Atomic Absorption Spectrometer coupled with a hydride and cold vapour generator. The concentrations of trace elements varied greatly from one species to another and within each species. These values ranged from 0.007 mg/kg for Hg in C hippos to 354.84 mg/kg for Mn in P. fusca. The most contaminated species by trace elements were benthic organisms: M. perna (Cd, Pb, Hg), Pagurus sp. (Cr, Ni, Cu, Zn), G. paradoxa (As) and P. fusca (Mn). The average concentrations of trace elements found in species were, for the most part, above WHO standards except Hg in M. perna and G. paradoxa. The water-based bioconcentration factors (BCFw) reach 92.58 for Cd, 44.72 for Pb, 382.49 for Hg and 1514.34 for As in M. perna. It is therefore necessary to pay particular attention to this ecosystem and to put in place a better management plan.

11000-Year Record of Trace Metals in Sediments off the Southern Shandong Peninsula in the South Yellow Sea

Geochemical background values are the normal concentration of trace metals in the natural environment and sediment cores have been proved to be excellent samples to get these values. The trace metal (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, Li, and Co) concentration profiles along a sediment core are investigated to get the background values and to assess the depositional processes and contamination levels off the southern Shandong Peninsula, China. All the metals, except As and Hg, had similar concentration profiles with the highest average values during the period of 6 − 3 kyr. The high concentrations of As and Hg occurred before 6ka and during the period of 3 − 0 kyr. The difference in metal concentrations before and after 6 kyr was mainly attributed to the source of core sediments, which are derived from proximal sediment on the Shandong Peninsula before 6 kyr and the mixture of proximal sediment and Yellow River sediment after 6 kyr. The effects of particle size and human activity were mainly contributed to the metal concentrations since 6 kyr. The average concentrations of trace elements in sediments between 6 and 3 kyr were selected as background values. The principal component factor analysis indicate that the metals were from the natural sources throughout the observed depositional period, with the exception of As and Hg, which may had anthropogenic sources for the sediments from the bottom 2 m of the core. Their geoaccumulation indices indicate that the sediments were not contaminated for Cu, Zn, Cr, Cd, Pb, Ni, Li and Co, whereas they were contaminated recently for As and Hg due to the regional civilization and human activities.

Determination of the content of selected trace elements in Polish commercial fruit juices and health risk assessment

AbstractThe objective of the study was to determine the content of cadmium (Cd), lead (Pb), arsenic (As), aluminium (Al), thallium (Tl), antimony (Sb) and uranium (U) in the apple and orange juices and black currant nectar in relation to the kind of packaging. Also, probabilistic risk assessment (non-carcinogenic) was estimated by models including target hazard quotient (THQ and THQ*). Aluminium (Al) was present at the highest concentration in the analysed juices and nectars, with average concentration ranging from 1.34 mg/kg in orange juices (glass) to 4.26 mg/kg in black currant nectar (glass). Fruit juices and nectars kept in tetra pack packaging were characterised by elevated concentrations of Al and Sb, while the products in glass packaging contained significantly higher concentrations of As compared with the products in tetra pack packaging. Although the average concentrations of trace elements were lower than the standard limit, exposure to non-carcinogenic factors was demonstrated.

Co-distribution, possible origins, status and potential health risk of trace elements in surface water sources from six major river basins, Bangladesh

In this study, we appraised the concentrations of 8 major trace elements (TEs) in surface water sources from six river basins, Bangladesh: Meghna, Kartoya, Sitalakha, Teesta, Pashur and Rupsha River basins. Co-distribution, the status of water quality and potential health risks were assessed using statistical analyses, the entropy water quality index (EWQI), sodium adsorption ratio (SAR), spatial autocorrelation index (SAI), hazard index (HI), and Monte-Carlo (MC) simulation. The spatial variations of TEs concentrations differed notably among the studied river basins. The average concentrations of TEs (except Ni, As, and Zn) in six river basins exceeded the drinking water quality guidelines. About 20% of water samples in six basins were categorized as undrinkable to poor qualities for drinking uses, while good water quality for irrigation purposes. The entropy theory identified that Cr, Pb, and As are the key pollutants influencing the water quality. According to the results of non-carcinogenic risk, the hazard index (HI) values for adults and children surpassed the allowable limit (>1), demonstrating detrimental health effects on humans. The carcinogenic risk values of chromium (Cr) were much higher than As and Cd exposures which exceeded the benchmark recommended by US EPA (>10−6 to 10−4), with an elevated risk for adults than children through the oral intake as the primary exposure route. Overall, the results suggest that the local population exposed to surface water may pose an adverse health effect, thus, strict regulation and efficient management should be focused on Cr, Cd and As monitoring and appraisal in these basins.

Speciation, risks and isotope-based source apportionment of trace elements in soils of the northeastern Qinghai–Tibet Plateau

Trace elements in soils might cause contamination and ecological risks to the environment with increasing anthropogenic disturbance. This study investigated the distribution, speciation, risks and possible sources of 28 target trace elements in soils of the northeastern Qinghai–Tibet Plateau. The average concentrations of trace elements in soils of the study area ranged from 0.25 (Hg) to 697.38 mg kg−1 (Cr). The residual fraction was the dominant host of V, Cr, Cu, Sn, Sb Hg and REEs, while Co, Ni, Zn, Mo, Cd and Pb had large proportions in the non-residual fractions. Risk assessment code analysis showed that Cd should be recognized as a priority pollutant in the study area. Correlation analysis indicated that Pb, Cu, Zn, Cd and Sn might originate from the same or similar source. The 206Pb/207Pb and 208Pb/206Pb ratios of the soils were in the range of 1.166–1.224 and 2.031–2.122, respectively. The anthropogenic Pb contribution proportion was in the range of 0–53.92% for the study area. The anthropogenic Pb contribution was higher in the areas with more intensive anthropogenic activities. Heavy metals and excessive anthropogenic disturbance should be effectively controlled in the northeastern Qinghai–Tibet Plateau to maintain the ecological sustainability and human health of this fragile area.

Reconnaissance geological and geochemical studies of the Precambrian rocks in Erijiyan Area, Southwestern Nigeria: Implications for mineral exploration

Reconnaissance geological and geochemical studies were carried out on the rocks at Erijiyan area to determine its mineral potentials thereby providing a framework for its exploration. Ten fresh rock samples were collected using grid controlled sampling method at a sampling density of one sample per 100sq km2. The rocks were subsequently prepared for petrographic studies followed by geochemical studies. The petrographic studies involve thin sectioning of the rocks into slides using the standard procedures while the geochemical studies include sample preparation and analyses for its major oxides and trace elements using Inductively Coupled Plasma Spectrophotometry (ICP-MS). The result of the geological mapping revealed three distinct lithologic units such as quartz schists, quartzites and pegmatites with well delineated boundaries, and the major or dominant foliation trend in the NE-SW direction. However, the results of the petrographic analysis showed dominant quartz with minor specks of muscovite while results of geochemical analysis revealed the dominance of Al2O3 and SiO2 with the quartz having an average percentage composition of 64.73%. Al2O3 indicated presence of aluminosilicate-bearing minerals such as feldspar, micas, and feldspathoids. The results of the trace elements analyses revealed that Mn is the most abundant with an average value of 1065.2 ppm while the average concentrations of other trace elements showed that Ba (1166.9 ppm), Zr (819.4 ppm), Sr (227.9 ppm) and Zn (130.7 ppm). Conclusively, The weathering index shows that the rocks in the study area are moderately weathered implying that the rocks are suitable for geochemical or mineralogical exploration.Considering the geochemical properties of the rocks in the study area, It could be deduced that Pb, Cu, Zn concentration is indicative of copper-zinc or sulphide mineralization. while. Pb, Sr, Ba and Zr also indicated the radio active nature of the rocks.

A comparison of bulk versus laser ablation trace element analyses in banded iron formations: Insights into the mechanisms leading to compositional variability

Banded iron formations (BIF) represent one of the few chemical sedimentary archives available for exploring the redox state of the Precambrian atmosphere-ocean system and the marine availability of biologically critical trace nutrients through time. Temporal records compiled for a number of trace elements show a relatively wide spread in concentrations spanning several orders of magnitude within a single deposit. It has been suggested that this spread is present in both bulk rock digestion and laser ablation data, however, the comparability of data from the two methods has not been thoroughly evaluated. Here, we provide a statistical assessment of how comparable laser ablation data of individual BIF hematite and magnetite grains are to one another, as well as how closely averages of laser ablation data approximate bulk rock values. To do so, we use (laser ablation)-high resolution inductively coupled plasma mass spectrometry ((LA)-HR-ICP-MS) data from 14 BIF slabs and corresponding powders that span four different formations. We focus in particular on BIF from the ≥3.75 Ga Nuvvuagittuq Supracrustal Belt (Québec, Canada) and multiple BIF deposits of the 2.6–2.45 Ga Hamersley Group (North Western Australia), representing deposits separated by over a billion years and of differing metamorphic grade. The scaling between selected transition metals is also evaluated in light of expectations for possible delivery mechanisms of trace elements from seawater to BIF precursor sediments – the adsorption to hydrous ferric oxides, biological vectors, and detrital influence. Our findings show that average trace element concentrations between bulk versus laser ablation data typically vary within an order of magnitude. Furthermore, reproducibility between the two methods appears to be independent of formation age, metamorphic grade, or depositional setting. These findings underscore the overall fidelity of the BIF record at capturing seawater compositional signatures at various scales. We demonstrate that evaluations of ancient seawater chemistry using the BIF record are best served by a combined approach utilizing both bulk rock and laser ablation data, as bulk methods offer the most conservative proxy data for ancient seawater composition but may mask significant enrichments or depletions that are detectable at the grain-scale by laser ablation.

Ecological Consequences of the Development of Shale Formations Containing Toxic Elements

Abstract—The average concentrations of trace elements, including toxic elements, in shales from various shale basins of the world are reported. The concentrations of a number of elements significantly exceeding the Clarke numbers for clay rocks in the Kenderlyk shale of the Republic of Kazakhstan, in the Domanic sediments of the Volga–Ural oil and gas bearing basin, some American formations (Barnett), etc., were noted. It was demonstrated that the concentrations of potentially toxic elements in many deposits were higher than their average values in clays and other sedimentary rocks. The release of potentially toxic elements into the environment significantly increased as a result of thermal effects on the formation, which can occur on the development of similar deposits of fossil fuels and in some hydrocarbon conversion processes. This was confirmed by natural observations and laboratory studies. On the hydraulic fracturing, which is widely used in the development of shale formations by the horizontal drilling method, toxic elements from both shales and their naphthide components can be released into the environment. In the development of shale deposits, additional studies are required for the monitoring of the trace element composition of shale formations to exclude environmental risks.

Distribution, pollution, bioaccumulation, and ecological risks of trace elements in soils of the northeastern Qinghai-Tibet Plateau

Environmental quality of the northeastern Qinghai-Tibet Plateau has attracted more attention due to increasing anthropogenic disturbance. Therefore, this study investigated the distribution, pollution, ecological risks, and bioaccumulation of 12 target heavy metals and 16 rare earth elements (REEs) in soils of this area. The average concentrations of target trace elements in soils ranged from 0.16 (Hg) to 500.46 (Cr) mg/kg. Pb caused more serious pollution than the other elements based on geo-accumulation index evaluation. Hg exhibited the strongest enrichment feature with the average enrichment factor of 8.41. Compare with modified contamination degree and pollution load index, Nemerow pollution index method obtained the most serious evaluation results that 45.67% and 16.54% of sampling sites possessed high and moderate pollution. Evaluation results of potential ecological risk index showed that trace elements in soils posed very high and considerable ecological risks in 34.65% and 7.09% of sampling sites, respectively. Mining area was the region with the most serious pollution and ecological risks. Average bioaccumulation factor (BCF) values of target trace elements ranged from 0.05 (REEs) to 2.67 (Cr). Cr was the element that was easier to bio-accumulate in plants of the study area than the other target elements. It is in urgent need to take effective measures for controlling current pollution and potential ecological risks of trace elements in soils of the northeastern Qinghai-Tibet Plateau.

Relationship Between Soil Physico-chemical Parameters and Trace Element Concentrations in Clay Loam Soil in West EL-Fashir City, North Darfur State, Western Sudan

Monitoring of trace elements in soil provides efficient way to assess the qualitative and quantitative differences in element concentrations at different sites within a region. The aim of the study was to assess levels of trace elements regarding accumulation of the metals, as well as investigate whether of the soil factors (chemical and physical) which influence trace element concentrations in soil. The physico-chemical parameters (viz. pH, EC, MC, OC, and textural class) and trace elements concentrations i.e Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn have been determined in the soils from caly loam region in west AL-Fashir city, Western Sudan. The top soil of this region is predominantly loamy sand. The soil pH varies within the acidic or slightly neutral and range between 6.62 – 7.72. The EC values were found to vary between 0.155-0.360. OC is very low (mean 0.081&plusmn;0.007). MC range between 0.230 – 0.430%. Average trace element concentrations decreased according to: Fe-Co-Ni-Cr-Zn. The sub-soil of this region is predominantly loamy sand. The soil pH varies within the range 6.02-7.10. The EC values were found between 0.162-0.275. OC is very low (mean 0.093+0.020). MC range between 0.230-0.430%. Average trace element concentrations decreased according to: Fe -Mn-Cr-Zn. The t-test showed that, elemental pairs: Ni-Cd, Cd-Cr, Mn-Cr, Pb-Cd, Cu-Cr, Cu-Cd, Cu-Mn, Zn-Cd, Fe-Mn, Fe-Pb, Fe-Cr, and Fe-Mo were showed significant differences in their concentrations in the study region, top-soil. In the top-soil, pH was high positively correlated with silt (r=0.760), whereas in the sub-soil, pH was highly positive correlated with EC (r= 0.755). The extraction of trace elements from soils of North Darfur for industrial use (especially, Fe, Cr and Cu) should be investigated.

A comparison of sample preparation strategies for biological tissues and subsequent trace element analysis using LA-ICP-MS

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is one of the most commonly applied methods for lateral trace element distribution analysis in medical studies. Many improvements of the technique regarding quantification and achievable lateral resolution have been achieved in the last years. Nevertheless, sample preparation is also of major importance and the optimal sample preparation strategy still has not been defined. While conventional histology knows a number of sample pre-treatment strategies, little is known about the effect of these approaches on the lateral distributions of elements and/or their quantities in tissues. The technique of formalin fixation and paraffin embedding (FFPE) has emerged as the gold standard in tissue preparation. However, the potential use for elemental distribution studies is questionable due to a large number of sample preparation steps. In this work, LA-ICP-MS was used to examine the applicability of the FFPE sample preparation approach for elemental distribution studies. Qualitative elemental distributions as well as quantitative concentrations in cryo-cut tissues as well as FFPE samples were compared. Results showed that some metals (especially Na and K) are severely affected by the FFPE process, whereas others (e.g., Mn, Ni) are less influenced. Based on these results, a general recommendation can be given: FFPE samples are completely unsuitable for the analysis of alkaline metals. When analyzing transition metals, FFPE samples can give comparable results to snap-frozen tissues.Graphical abstractSample preparation strategies for biological tissues are compared with regard to the elemental distributions and average trace element concentrations.