High Concentrations Of Trace Elements Research Articles

Risk assessment and source apportionment of trace elements in multiple compartments in the lower reach of the Jinsha River, China

Studies on trace element (TE) pollution in abiotic matrices have typically focused on water, sediment, and soil, either separately or in pairs. The importance of multi-media connectivity has been ignored. This study analyzed the concentrations of 6 TEs in three connected environmental compartments of a 28-km section of the lower reach of the Jinsha River. The ecological risk posed by TEs was higher in soil than in sediment. The contribution of exposure pathways to human health risk were ranked as ingestion > dermal contact > inhalation. An improved regional environmental risk index (RERI) method was then developed to evaluate the comprehensive risk on both ecology and human health caused by TEs. The average RERI value was generally higher in the wet season (0.42) than in the dry (0.41) and dry-to-wet transition seasons (0.08) because of the combined effects of the high TE concentrations in riparian soil and the long exposure time. Source apportionment indicated that industrial activities, weathering of parent rock, and agricultural activities were possible sources of TEs in this region. The methods and results of this study could inform local environmental management and provide references for similar cases wherein multiple compartments of river systems should be considered.

Possible occurrence of Palaeoarchean ferropicrite cumulates and ferrobasalts in the Jojohatu area of North Singhbhum Craton, eastern India: Evidence for a mantle plume source

An occurrence of Palaeoarchaean ferropicrite cumulates and ferrobasalts is being reported from the Jojohatu area of the Iron Ore Group (IOG) greenstone belt, which is situated in the northern part of the Singhbhum Craton (eastern India). The ferropicrite cumulates contain serpentine and clinopyroxene as major constituents and spinel, magnetite, and ilmenite as accessories. Their bulk rock chemistry exhibits an extremely high amount of FeOT (19.0–20.8 wt%) and MgO (22.0–23.9 wt%) and quite low Al2O3 (4.5–5.2 wt%) and Na2O + K2O (<1.0 wt%), thus making them as one of the most Fe‐rich ferropicrite cumulates in the world. They are also characterized by high contents of compatible trace elements (Ni: 986–1,470 ppm; Cr: 990–1,256 ppm) and moderate TiO2 (1.5–1.7 wt%), Nb (15–18 ppm), and Zr (82–90 ppm). These cumulates are possibly formed due to accumulation of olivine from the ferrobasaltic melts. In comparison, ferrobasalts consisting of plagioclase, pyroxene, and opaques are alkaline in nature. Some of the plagioclase and pyroxene grains have shown a signature of metasomatic alteration, which resulted into formation of secondary minerals such as epidote, chlorite, and hornblende. They exhibit relatively low contents of FeOT (14.6–18.4 wt%), MgO (8.4–10.8 wt%), Ni (32–122 ppm), and Cr (41–131 ppm) than the ferropicrite cumulates, while TiO2 (2.9–4.1 wt%), Nb (42–61 ppm), and Zr (216–318 ppm) contents are higher. Incompatible elemental patterns and their ratios, as well as Zr/Y versus Nb/Y plot, indicate their ocean island basalts (OIB) affinity and genesis from a hot mantle plume, having mantle potential temperature of about 1,600°C and pressure of 3.5–5 GPa. Considerably low CaO (3.00–7.16 wt%) and FeO/MgO and CaO/MgO systematics indicate that the primary source of the basaltic melt could be pyroxenite. These volcanic occurrences possibly represent remnants of the OIB formed during the Palaeoarchean in the eastern part of the Indian shield.

The influence of the physicochemical properties of sediment on the content and ecotoxicity of trace elements in bottom sediments

The sorption mechanisms of the trace elements in bottom sediment are not fully understood. The study aim was to analyse the effect sorption capacity of bottom sediments on the content of trace elements and the bottom sediment ecotoxicity. The study found higher content of trace elements caused higher potential toxicity of bottom sediments. However, the PCA analysis indicated that ecotoxicity to Heterocypris incongruens was not related to the trace element content in the sediments. It was found that some of the physicochemical properties of bottom sediments determine the behavior of the test organism. The study revealed a strong relationships between the properties of bottom sediments and trace element sorption, which results from significant differences in the carbonate and organic matter contents. The obtained relationships showed a significant role in trace element sorption of negatively dissociating functional groups (carboxyl, phenolic, alcohol, and carbonyl groups) of Cha, Cfa, Cnh and DOC fraction and of clay minerals. Positive correlation between the metal content and the volume of ultramicropores, cryptopores and residual pores suggest that these pore groups contain reactive sites capable of effective element sorption. In contrast, larger pores turned out to be of marginal importance in trace elements sorption, probably participating only in their migration within the bottom sediment structure. An understanding of the above factors will provide comprehensive information on the fate of trace elements in aquatic systems.

Dissolution and Reprecipitation of Garnet during Eclogite-facies Metamorphism; Major and Trace Element Transfer during Atoll Garnet Formation

AbstractGarnet commonly accommodates high contents of Mn + Y + heavy rare earth elements (HREE) that follow Rayleigh fractionation during garnet early growth, with the exception of overstepping nucleation (late crystallization owing to reaction overstepping). Because of this, as the garnet porphyroblasts form mostly in equilibrium with the surrounding matrix, the concentration of these elements continuously decreases towards the porphyroblast rims. Yet rapid changes in the reaction progress of a rock during garnet growth, namely the resorption–dissolution of minerals with high concentrations of Y + REE, may create an anomaly or peak in the mantle or rim of garnet grains. In this study we present an example of the resorption of garnet cores and formation of atoll garnet textures in eclogite from the Krušné hory (in the Saxothuringian tectonic zone of the Bohemian Massif). Based on textural relations, we show that the atoll garnet grains in the studied rocks were formed during the prograde stage from blueschist- to eclogite-facies metamorphism. Preliminary observations showed that the full (non-atoll) garnet grains had compositionally different cores (interior, or garnet I) and rims (ring, or garnet II) that were separated by a Y + HREE + medium REE (MREE) concentration peak. The ring garnet II indicated an elevated concentration of Mn in comparison with the marginal parts of the interior garnet I. Therefore, minor elements that were less vulnerable to diffusion than major elements and strongly sensitive to the broad spectrum of geochemical processes, such as Y + REE, were used to track possible mineral reactions during the whole garnet growth path. Thermodynamic modelling indicated the formation of garnet by the breakdown of chlorite and lawsonite/zoisite, and peak-pressure phases were represented by garnet, omphacite, quartz, amphibole, rutile, and talc. To quantify the sources of high Mn concentrations in garnet II and of the Y + HREE + MREE sharp peaks, the sequences of mineral reactions and dissolution of garnet I leading to the formation of the atoll structure were investigated. In addition to thermodynamic modelling and pressure–temperature path constraints, mass-balance calculations of trace elements were also performed. The results combined with the observed compositional and textural relations indicate that the concentrations of Mn + Y + HREE + MREE in garnet II and the concentration peaks at the interface of the two garnet types were controlled by a complex mechanism that included the dissolution of garnet I during the formation of the atoll texture, stepwise growth of garnet during increasing pressure and temperature, and decomposition of phases with high concentrations of trace elements, such as zoisite/epidote or lawsonite.

Beneficial use of the aqueous phase generated during hydrothermal carbonization of algae as nutrient source for algae cultivation

Hydrothermal carbonization converts algal biomass to hydrochar, but also generates a waste aqueous phase rich in nitrogen and other elements that need to be treated before discharge into water bodies. At the same time, cultivation of microalgae requires significant amounts of nutrients, such as nitrogen, phosphorous, and trace metals. Utilization of aqueous phase in algae cultivation can potentially reduce algae production cost, while mitigating waste generation, leading to a circular process that enhances the sustainability of algal biofuels and bioproducts. In the present study, we assessed the potential of aqueous phase generated during hydrothermal carbonization of lipid-extracted algae to support algal biomass and lipid production from Chlorella vulgaris. The aqueous phase was found to contain high concentrations of nitrogen (2.4 g/L), phosphorus (1.75 g/L), organic carbon (20.9 g/L), and trace elements. Among several aqueous phase dilutions in non-sterilized water (2.5–7.5% v/v) tested for algae cultivation, maximum lipid productivity that was 1.7-fold higher than with standard cultivation media was achieved when C. vulgaris was grown in 5% aqueous phase. Time course studies showed significant nutrient removal of 95% nitrate, 60% ammonia, 47% phosphate, and 30% organic carbon by C. vulgaris over the course of a 10-day cultivation. Moreover, when compared with standard media, utilization of the aqueous phase resulted in augmentation of both storage and structural algal lipids that can be used for biofuel and nutraceutical production, respectively. Subsequent bench-top photobioreactor cultivation validated that the aqueous phase is a promising cultivation medium for algal product manufacturing.

Biochar ageing in polluted soils and trace elements immobilisation in a 2-year field experiment

Biochar application to soils has become a focus of research during the last decade due to its high potential for C sequestration. Nevertheless, there is no exhaustive information on the long-term effects of biochar application in soils contaminated with trace elements. In this work, a 2-year field experiment was conducted comprising the application of different types of biochar to acidic and moderately acidic soils with high concentrations of As, Cu, Pb, Ba and Zn. In addition, representative samples of each biochar were buried in permeable bags that allowed the flow of water and microorganisms but not their physical interaction with soil aggregates. The biochars significantly adsorbed trace elements from polluted soils. However, given the high total concentration of these persistent trace elements in the soils, the application of biochars did not succeed in reducing the concentration of available metals (CaCl2 extractable fraction). After 2 years of ageing under field conditions, some degradation of the biochars from olive pit, rice husk and wood were observed. This study provides novel information concerning the biochar alterations during ageing in polluted soils, as the decrease of aryl C signal observed by 13C nuclear magnetic resonance (NMR) spectroscopy and the presence of O-containing groups shown by Fourier Transform mid-Infrared Spectroscopy (FT-IR) in aged biochar which enhanced trace elements adsorption. Scanning electron microscopy (SEM) revealed slight changes on surface morphology of aged biochar particles.

Hydrochemical characteristics, trace element sources, and health risk assessment of surface waters in the Amu Darya Basin of Uzbekistan, arid Central Asia.

Thorough knowledge of hydrochemical characteristics and trace element concentrations in surface waters is crucial for protection of this resource, especially in arid regions. Uzbekistan lies in central, arid Central Asia, and is experiencing severe water scarcity as a consequence of warming climate and accelerated human impacts. Fifty-five surface water samples were collected from the Amu Darya Basin of Uzbekistan (ADBU) and measured for relevant variables, to determine hydrochemical characteristics and evaluate water quality. River water samples from the middle reach and Amu Darya Delta (ADD) were dominantly HCO3-Ca and SO4-Ca·Mg types, respectively, whereas water samples collected near the former shoreline and sewage outlets in the ADD were predominantly Cl-Ca·Mg and Cl-Na types, consistent with the distribution of sites that display high concentrations of trace elements and are seriously affected by human activities. Principal component analysis indicated that Pb and Cd in surface waters of the ADBU had industrial origins. Local agricultural activities are thought to have contributed to the concentrations of NO3, Zn, Ni, Hg, and Mn, through pesticide and fertilizer applications, and concentrations of Cu, Cr, As, and Co are controlled by mixed natural and anthropogenic sources. Water quality and health risk assessments indicated that unsuitable drinking waters are distributed mainly near the former shoreline and sewage outlets in the ADD, making human health risks in these areas high.

Trees and shrubs from a post-industrial area high in calcium and trace elements: the potential of dendroremediation

The aim of the study was to evaluate the metal(loid)s phytoextraction potential of trees: Betula pendula Roth, Pinus sylvestris L. and the shrub Salix viminalis L. Plants of different ages were selected from a post-industrial area with an unusually high content of calcium (Ca) and trace elements in the soil. The content of 39 metal(loid)s in trees and shrub organs and physicochemical soil parameters were determined. A comparison of these species with control plants was also an object of the study. The polluted soil was characterized by worse physicochemical conditions and a much higher content of almost all the analyzed elements in comparison with the control. The older the plants, the greater their total biomass, with the control plant biomass being significantly greater in each case for all treated plants. According to the total content of all determined elements jointly, the most enriched was the oldest, a 7-year-old specimen of S. viminalis. The obtained results suggest that the high Ca concentration and the alkaline reaction (8.83) of polluted soil limit the uptake of most elements by tested plants. It can be concluded that despite the reduction of biomass, this limitation allows plants to better adapt and survive under challenging conditions. Excessive concentration of elements, even nutrients such as Ca, may act as an inhibitory factor for the uptake of other elements. Moreover, phytoextraction ability may significantly vary in different woody plant species and ages, which is an essential practical aspect in dendroremediation application. Novelty statement That is probably the first study to date of trees and shrubs differing in age and growing on post-industrial soil contaminated with calcium (Ca) and selected toxic metals/metalloids. The obtained results show that an alkaline reaction (less than 9) of soil and an unusually high Ca concentration may help the studied tree species to adapt/survive in unfavorable habitat conditions (high concentration of toxic elements). The efficiency of phytoextraction of toxic elements was so high that, especially for forest animals (roe-deer) that consume, e.g., willow shoots, it could pose a serious threat to health and life, both for them and potentially for humans.

The relatively higher concentrations of trace elements to arsenic may have influenced on methylation process of inorg- As in humans

The relatively higher concentrations of trace elements to arsenic may have influenced on methylation process of inorg- As in humans

Diverging Water Ages Inferred From Hydrodynamics, Hydrochemical and Isotopic Tracers in a Tropical Andean Volcano-Sedimentary Confined Aquifer System

Hydrogeology in the Andes cordillera reflects its complex geological history. In most cases, groundwater flows through fractures and faults that compartmentalize the volcanic material, and through the primary porosity of the volcano-sedimentary material. The volcanic mineral context and geothermal environment mark the groundwater chemistry, especially in the high concentrations of specific trace elements. This study focuses on the complex system of the Tumbaco – Cumbayá – Los Chillos aquifer, in the vicinity of the Ilaló volcano near Quito (Ecuador). Hydrodynamic, geochemical and isotopic tools were used to assess the chemical characteristics of water and its origin, identify the recharge areas, and estimate the transit time of water using simple methods and scarce data. Results revealed two distinct aquifers, one in the volcanic cone located in the center of the study area, and the other in the volcano-sedimentary series of the Tumbaco – Cumbayá – Los Chillos valley. The volcanic aquifer is characterized by a high mineralization, a recharge zone between 2400 m asl and 3100 m asl, and radiocarbon concentrations lower than 20 pmc. The volcano-sedimentary aquifer seems to behave as a partly disconnected system, between the north and the south of Ilaló volcano, and also with a great heterogeneity, maybe due to the presence of lenses of volcanic ash. It has an intermediate mineralization, a mean recharge zone between 2,300 and 2,700 m asl, and 14C activities between 45.4 and 87.4 pmc in apparent contradiction with the hydrodynamic mass balance.

Mantle melting models of the Kızıldağ ophiolite in SE Turkey: Two types of partial melting processes in the oceanic upper mantle of southern Neo-Tethys

Many ophiolites in southern Neo-Tethys contain complete lithologic sequences, with the dikes and lavas commonly having highly variable geochemical compositions. In this study, we examine the sheeted dikes and layered and isotropic gabbros of the Kızıldağ ophiolite (southern Turkey) and suggest that the compositional variations of the rocks are likely related to melting models of the mantle. The sheeted dikes and gabbros of the ophiolite have 206Pb/204Pb(90 Ma) of 17.765–19.361, 207Pb/204Pb(90 Ma) of 15.570–15.665 and 208Pb/204Pb(90 Ma) of 37.812–39.269, straddling the fields of Indian Ocean MORB and modern marine sediments. The sheeted dikes have low rare earth element (REE) concentrations and LaN/YbN ratios (e.g., Yb < 2.5 ppm and LaN/YbN of 0.33 to 0.62 on average), comparable with those of forearc basalt (FAB), except for a few samples whose trace element concentrations and patterns are similar to those of boninite. All the studied samples have positive anomalies of large ion lithophile elements (LILE) (e.g., Rb, Ba, Th, U and Sr) on a N-MORB-normalized trace element diagram and show considerable scatter on the plot of Th/Yb vs. Nb/Yb, which is attributed to involvement of slab-derived melts/fluids in a protoarc-forearc setting. Thermodynamic modelling results suggest that the parental magmas of the sheeted dikes were combined melts derived by both polybaric continuous melting (<10%) and flux-melting (<25%) of the mantle wedge during subduction initiation. In contrast, clinopyroxene and plagioclase in the layered and isotropic gabbros have compositions similar to those of boninite. The gabbro compositions can be simulated by batch crystallization of the boninitic melts, and the relatively high trace element concentrations of some isotropic gabbros likely reflect a high fraction of interstitial liquid in the crystal mush. Thus, we propose that the compositional variations of the sheeted dikes reflect two types of mantle melting, and that the gabbros were produced by subsequent crystallization within a crystal mush having variable fractions of interstitial liquid. Not only can such complex magmatic processes explain the observed compositional variations of dikes and lavas of the Kızıldağ ophiolite, but may be appliable to other ophiolites in southern Neo-Tethys, such as the Lycian, Pozantı-Karsantı and Troodos massifs.

Citric acid-assisted phytoextraction of trace elements in composted municipal sludge by garden plants

Sludge landscaping after compost stabilization is a popular recycling process; however, until trace elements (TEs) are extracted by plants and reduced to safe concentrations, they present a potential exposure risk. Three garden plants, Liriope platyphylla Wang et Tang (L. platyphylla), Iris tectorum Maxim (I. tectorum), and Photinia x fraseri Dress (P. x fraseri), were selected for field experiments, and their ability to phytoremediate TEs and the promotion effect of citric acid (CA) were studied over 3 months of observation. Among the three kinds of plants, L. platyphylla had the highest biomass per unit soil area, and the CA treatment further increased the biomass of this plant per unit soil area as well as the uptake of TEs. When treated with 3 mmol kg−1 CA, L. platyphylla showed increases in the bioconcentration factors of Cu, Zn, Pb, and Cd by 24%, 63%, 27%, and 123%, respectively. Because of the large biomass and high concentrations of TEs, L. platyphylla had high phytoremediation indexes for Zn, Cu, Pb, Ni, and Cd, which reached 18.5, 3.7, 3.2, 2.2, and 0.4 mg m−2, respectively, and were further improved by 60%–187% by the CA treatment. These advantages indicate the potential usefulness of L. platyphylla for phytoremediation. The results provide basic data and technical support for the use of sludge-based compost and phytoremediation by garden plants.

ОЦЕНКА МЯСНОЙ ПРОДУКТИВНОСТИ И КАЧЕСТВА МЯСА ТЕЛЯТ, ПОЛУЧАВШИХ КОРМОВЫЕ ДОБАВКИ НА ОСНОВЕ ХЕЛАТНЫХ КОМПЛЕКСНЫХ СОЕДИНЕНИЙ И НЕОРГАНИЧЕСКИХ СОЛЕЙ МЕТАЛЛОВ-МИКРОЭЛЕМЕНТОВ

The influence of the use of feed additives used in the cultivation of calves on the quality of their meat and meat productivity was studied. Calves were given two types of liquid feed additives: 1) freshly prepared solutions of inorganic salts of copper, zinc, cobalt, iron and manganese; 2) solu-tions of chelated complex compounds of these trace elements. A fractional - periodic scheme of their administration was used, which minimizes the effect of physiological antagonism of trace ele-ments. It was shown that the meat of animals treated with complex compounds had a higher content of trace elements and better indicators of fat content and protein.

Baseline Concentrations of 11 Elements as a Function of Land uses in Surface Soils of the Katangese Copperbelt Area (D.R. Congo)

The Katangese Copperbelt Area (KCA) located south-eastern of D.R. Congo presents high concentration of Metal Trace Elements (MTE) due to a rich natural geochemical background and intense mining activities. However, the lack of data on specific baseline concentrations makes it difficult to assess and monitor the environmental quality of soils in the region. In this study, 11 MTE were measured across three land uses (croplands, forest and mining areas) to assess their baseline concentrations in topsoils of the KCA. Results showed the following (geometric) mean concentrations (mg.kg-1) in cropland soils: Al (54.6), Co (0.5), Cr (0.1), Cu (3.7), Fe (33.0), Mn (44.8), Ni (0.2), Pb (0.6), Zn (1.0), Ti (2.4), pH (5.3); in forests: Al (148.0), Cd (0.1), Co (1.9), Cr (2.2), Cu (12.3), Fe (156.4), Mn (86.9), Ni (1.1), Pb (1.9), Zn (3.7), Ti (0.4), pH (4.3); and in mining areas: Al (42.8), Cd (1.3), Co (7.0), Cr (0.1), Cu (115.5), Fe (53.3), Mn (26.1), Ni (0.5), Pb (8.2), Zn (93.1), Ti (0.3), pH (5.8). Cu and Zn were higher in mining areas compared to other land uses, demonstrating a prevalent influence of mining activities in altering the natural background of metals concentrations in the region. By contrast, croplands and forest shared a similar trend of Al and Mn contents, suggesting a mild influence of agricultural activity. This study is the first attempt to establish reference values of MTE contents in the KCA soils and thus provides valuable information for legislative purposes and for soil quality assessment.

Assessment of dust trace elements in an e-waste recycling area and related children's health risks

Children from Guiyu, an electronic waste (e-waste) recycling town, are exposed to trace elements via dust. However, the source, pathways, and influence factors of house dust and the association of house dust with child inflammation in an e-waste recycling area are not well-known. This study investigated dust trace elements in children's living environment and the associations of house dust trace elements with influence factors and child inflammation. A total of 108 dust samples from children's residences, roads, and kindergartens in Guiyu (an exposed area) and Haojiang and Shantou urban areas (reference areas) were collected and analyzed, as well as children's questionnaire data.The Mann-Whitney U test found there were higher trace element concentrations in road dust (Co, Ni, and Cu), kindergarten dust (Al, V, Mn, Co, Ni, and Zn), and house dust (V, Co, Cu, As, and Cd) in Guiyu than in Haojiang and Shantou urban areas (P < 0.05). Our analysis showed that house dust and road dust have similar distribution patterns of trace elements. Spearman's correlations showed close relationships among quantities of trace elements (P < 0.05).Higher trace element concentrations in dust were found in houses that used indoor shoe cabinets and opened windows frequently (P < 0.05). In houses of children with airway inflammation, higher dust Ba concentrations were found (P < 0.05), and if their fathers did not work with e-waste, we found higher dust Pb concentrations (Mann-Whitney U test, P < 0.05).Health assessments showed a high risk of exposure through ingestion and an acceptable risk of exposure through inhalation of dust trace elements for children. However, relationships between airway inflammation and house dust trace elements showed the inhalation risk might be underestimated. This study suggests trace element exposure via dust poses a health risk for children living in e-waste recycling areas.

Chemistry of Tropical Eucheumatoids: Potential for Food and Feed Applications.

The use of seaweeds as additives in animal nutrition may be a valid option to traditional feed as they represent a rich source of minerals, carbohydrates and antioxidants. The aim of this study was to analyze the chemical composition and in vitro antioxidant capacity of two tropical eucheumatoids, Kappaphycus alvarezii and Kappaphycus striatus, in Malaysian wild offshore waters. The chemical analysis was performed via inductively coupled plasma–optical emission spectroscopy for evaluating the concentration of toxic (Cd, Pb, Hg, As) and essential elements (Mn, Fe, Cu, Ni, Zn, Se); NMR spectroscopy was used for carrageenans investigation. Furthermore, the soluble and fat-soluble antioxidant capacities were determined by FRAP, DPPH and ABTS assays. The chemical analysis revealed a higher content of trace elements in K. alvarezii as compared to K. striatus, and both exhibited a high mineral content. No significant differences in metal concentrations were found between the two species. Both samples showed a mixture of prevailing κ- and t-carrageenans. Finally, the levels of soluble and fat-soluble antioxidants in K. alvarezii were significantly higher than in K. striatus. Our findings suggest that K. alvarezii could be used as a potential feed additive because of its favorable chemical and nutritional features.

Occurrence and Release of Trace Elements in Pyrite-Rich Waste Rock

Waste rock can contain high concentrations of deleterious trace elements, which upon oxidation can be released, having a significant impact on water quality. Therefore, knowledge about their occurrence and overall mobility is crucial to ensure suitable environmental protection measures. Sulfide-rich waste rock was characterized and quantified using automated mineralogy (QEMSCAN). Selected pyrite grains were analyzed for trace element occurrence using LA-ICP-MS before, during, and after leaching the waste rock in 10 L small-scale test cells for two years to assess trace element occurrence and mobility. Sequential extraction was used to estimate elemental sequestration during the experiment. The high abundance of pyrite (66%) and scarcity of buffering minerals resulted in low pH (&lt;1.3) leachate with high concentrations of trace elements such as As (21 mg/L), Cu (20 mg/L), Hg (13 µg/L, Pb (856 µg/L), Sb (967 µg/L), Tl (317 µg/L ), and Zn (23 mg/L) in solution with limited retention in secondary minerals, primarily due to these elements’ association with pyrite either as inclusions or impurities showing an average abundance of 193 ppm As, 15 ppm Cu, 13 ppm Hg, 20 ppm Pb, 24 ppm Sb, 26 ppm Tl, and 74 ppm Zn in the waste rock. The occurrence of Cu and Zn as inclusions associated with the pyrite led to their extensive mobilization of 79% and 72%, respectively, despite their low abundance in the waste rock. Provided the overall leachability of S (11%) and limited formation of secondary minerals, the average oxidation rate suggests depletion of the pyrite within approximately 18 years. In conclusion, this study shows the importance of detailed mineralogical investigations and early preventive measures of waste rock to ensure sustainable mine waste and water management.

Characterization of an Endemic Plant Origanum grosii from Morocco: Trace Element Concentration and Antihyperglycemic Activities

Origanum genus is one of the most widely used herbs in folk medicine for its biological properties. The present investigation aims to characterize, for the first time, endemic Origanum grosii collected from the Taounate region, Morocco. This characterization was realized by determining the concentration of metals in different parts of the plant (flowers, leaves, and stems) by ICP-MS, and the results were studied statistically by Principal Component Analysis (PCA). Phytochemical screening with the dosage of polyphenols and flavonoids has been conducted. To know more about this species, antihyperglycemic tests have been performed to highlight the presence or absence of the antidiabetic effect for this plant. An Oral Glucose Tolerance Test (OGTT) has been performed on normal mice which were divided into two groups of six mice each. Group 1 (control group) was treated with distilled water, and group 2 was treated with an aqueous extract of O. grosii by gavage at 150 mg/kg. Digestive enzyme α-amylase inhibition assay has also been evaluated to study the inhibition effect of the studied extract using acarbose as a control. The results showed that the leaves exhibited a high concentration of trace elements (Ca, Mg, and K) and total absence of heavy metals, which were found in small quantities (Cr, Ni, and B) on the stems, and this makes the plant safe to use. On the other hand, tannins, flavonoids, triterpenes, and steroids were the major families strongly present in this species. The antidiabetic results showed that O. grosii have significantly reduced postprandial hyperglycemia after glucose loading in normal rats. It showed also that this species has a significant antihyperglycemic activity reflected by the inhibition of α-amylase. The one responsible for this property could be the synergy between the trace elements and the nature of the chemical families of O. grosii species, which can make this plant useful in the management of postprandial hyperglycemia.

Predicting the relative oral bioavailability of naturally occurring As, Cd and Pb from in vitro bioaccessibility measurement: implications for human soil ingestion exposure assessment

Chestnut soils developed over mineralized areas of southwestern Spain are characterized by high baseline concentrations of geogenic trace elements, notably Pb (up to 14,562mgkg-1), As (up to 346mgkg-1) and Cd (up to 319mgkg-1), which could pose an unacceptable risk to the health of the hand-harvest workers who are being exposed to surface soil by incidental ingestion and dermal contact. Oral bioaccessibility, as determined by simulating the human digestion process in a test-tube environment (Unified BARGE Method), followed the increasing order of As (3.1%) < Pb (21.5%) < Cd (35.6%) in the gastric phase, and As (3.4%) < Pb (4.5%) < Cd (13.2%) in the gastrointestinal extract. Relative bioavailability (RBA) of As (3.1-2.1%), Pb (17.8-17.5%) and Cd (34.4-23.3%), predicted from in vitro bioaccessibility measurement through linear regression models, seems to be influenced not only by the pH and composition of digestive solutions but also by geochemical partitioning of trace elements among the soil constituents. The integration of RBA data in the risk calculations had a considerable effect on the site-specific risk estimations. After RBA adjustment, the level of carcinogenic risk associated with As exposure (< 1.5E-06) and the hazard index for non-carcinogens (< 0.4) was within the regulatory limits, indicating that occupational risks are not of concern. Hence, it can be concluded that the use of a default value of 100% for bioavailability may dramatically overestimate the chronic exposure to geologically sourced trace elements.

Trace-element systematics and isotopic characteristics of sphalerite-pyrite from volcanogenic massive sulfide deposits of Betul belt, central Indian Tectonic Zone: Insight of ore genesis to exploration

• Co/Ni ratio of pyrite characterized submarine-magmatic hydrothermal ore process. • High-temperature VMS system > 300 °C formed from multiple sulfur sources. • Geochemical trends in sphalerite and pyrite by LA-ICP-MS suggest VMS-type deposits in the Betul belt. • PCA on pyrite and sphalerite helps in the reconstruction of the metallogeny and exploration prospectivity. • Chalcopyrite disease in sphalerite reflect high-temperature ore fluid and metamorphism . The Paleoproterozoic volcanogenic massive sulfide (VMS) deposits in the Betul belt (BB) (ca.1.7 Ga) in central India are well-known for their low-grade Zn-Cu-Pb sulfide mineralization. The physicochemical conditions of ore formation, size, grade, extent, and nature of mineralization are the ongoing debates and concerns to the exploration agencies for the last two decades. Field examination, drill core analysis, petrography, and scanning electron microscopic studies reveal the occurrence of chalcopyrite, sphalerite, pyrite, galena with minor pyrrhotite in the form of dissemination, stringers, and semi-massive sulfide veins. We present the minor-trace element contents in sphalerite and pyrite from drill core samples of four deposits (Banskhapa, Jangaldehri, Biskhan, and Bhuyari), analyzed by electron probe microanalyzer (EPMA) and in-situ laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) for determining ore-forming temperature, ore genesis and exploration prospectivity. The EPMA and LA-ICP-MS studies of sphalerite display a slightly high concentration of trace elements like Mn, In with a mean value of 3533 ppm and 33 ppm, respectively. On the other hand, Ga, Ge, and Ag content are low in abundance along with a low concentration of Bi, Pb, and Sb in all four deposits. Pyrites show low Ni and high Co/Ni (mostly > 1) ratios and variable Ti, Se, As, and Mn. Multivariate statistical analysis, especially the principal component analysis (PCA) of these trace elements, defines the geochemical variations among the Betul belt deposits. The ore-forming temperature is estimated using sphalerite thermometry (374 °C to 402 °C) and pyrite thermometry (225 °C to 484 °C). The geochemical discrepancies occur due to magmatic-hydrothermal activities caused by the sub-volcanic intrusions, followed by recrystallization and remobilization of the sub-microscopic inclusions during subsequent metamorphism. Additionally, sulfur isotope analysis provides insights into the sulfur source variations, metals, and mineralization. Carbon and Oxygen isotopes are used to understand the physicochemical conditions of the ore-forming environment. Sphalerite, pyrite, and chalcopyrite from Banskhapa deposit suggest a broad range of δ 34 S values (7.27–7.79‰, 8.37–8.61‰, and 6.58–6.72‰ respectively, n = 7), which advocate sulfur mostly derived by thermochemical reduction (TSR) of seawater sulfate with some input of magmatic sulfur leaching from the igneous basement. Carbon and oxygen isotope studies of carbonates from Jangaldehri and Bhuyari deposits (δ 13 C: −6.0 to −13.45‰ with an average value of −9.51‰, n = 7; δ 18 O: 7.32‰ to 20.58‰ with an average value of 15.65‰, n = 7) indicate that the carbonates formed from a hydrothermal fluid (seawater with an insignificant magmatic input), the mixing of hydrothermal fluid with ingressing seawater, or both in the mineralized zone. These processes collectively led to Zn-Cu and Zn-Cu-Pb mineralization in the Betul belt. High temperature, strong isotopic and trace element geochemical variations in sphalerites (Ag-Mn, In/Cd-Mn, In/Cd-Fe, Mn-In/Ge, Fe-In/Ge, Fe-In) and pyrite (Ni-Co, As-Cu, Ag-Au, and Se-Te) attest to the mineralization as being volcanogenic massive sulfide (VMS) deposits in Betul belt and differentiated from other genetic types like Mississippi Valley-type (MVT), sedimentary-exhalative (SEDEX), skarn, porphyry, and epithermal hydrothermal deposits.