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Semi-arid coastal aquifers face critical challenges characterized by lower rainfall, higher evaporation rates, and looming risk of over-exploitation. These conditions, coupled with climate change, are conducive to seawater intrusion and promote mechanisms associated with it. The understanding of metal behavior in such environments is limited, and hence, an attempt is made through this review to bridge the knowledge gap. A study on the behavior of trace metals within a specific context of semi-arid coastal aquifers was carried out, and 11 aquifers from 6 different countries were included. The review observed that trace metals within semi-arid coastal aquifers exhibit distinctive behaviors influenced by their surrounding environment. The prevalence of evaporation and continuous seawater intrusion played a pivotal role in shaping trace metal dynamics by curtailing groundwater flux. The findings suggest that the formation of stable Cl and organic ligands under increased alkaline conditions (pH > 8) has higher control over Zn, Pb, and Cd toxicity in a highly ionic reactive condition. In addition, dominant control of Fe/Mn-hydroxide association with Pb and high organic affinity of Zn played a pivotal role in controlling its bioavailability in aquifers such as WFB, Saudi Arabia NW-C and India. On the contrary, under prevailing acidic conditions (pH < 6), carbonate and SO4-ligands become more dominant, controlling the bioavailability/desorption of Cu irrespective of its origin. The behavior of Ni is found to be controlled by stable organic ligands increasing salinity. An increase in salinity in the considered aquifers shows an increase in bioavailability of Ni, except UmC, South Africa, where organic ligands act as a sink for the metal, even at low pH conditions (pH < 5.5). This study indicates that factors such as mineral saturation, carbonate complexes, pH variations (pH > 8), and chloride complexes govern the distribution of trace metals further enhanced by prolonged water residence time. Nonetheless, specific conditions, such as a reducing and acidic environment, could potentially elevate the solubility of highly toxic Cr (VI) released from anthropogenic sources. [ABSTRACT FROM AUTHOR]

Metals may be associated with plastics as additives arising from manufacture or through acquisition from the environment, but these associations are often poorly defined or referred to synonymously when considering metal availability. In this study, samples of plastic litter (n = 22) have been collected from various environmental and industrial compartments of Lublin Province, Poland, and fractionated according to polymer type (polyethylene, polyethylene terephthalate, nylon, expanded polystyrene, polypropylene, and "mixed") before being micronised to < 2 mm. Composites (n = 89) were subjected to two phases of a standardised and widely employed sequential extraction protocol (Bureau Communautaire de Reference; BCR) in order to define available (acid-soluble and exchangeable) and residual (soluble in boiling aqua regia) concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. For a given metal, total content, calculated by summing available and residual components, was highly variable, both between locations and amongst polymer categories, reflecting the heterogeneous distribution of a multitude of different additives. Overall, however, concentrations were greatest for Fe, with medians of several hundred to several thousand mg kg−1 amongst the different polymers, and lowest for Cd, Co, and Ni, where nearly all concentrations were below 10 mg kg−1. Median percentage metal availabilities were greatest for expanded polystyrene and were above 25% for Mn and Zn and below 10% for Cr and Fe in all polymer types. These observations are largely, but not entirely, attributed to the relative contributions of metals acquired from the environment and metals present as additives and residues. Significantly, the approach employed allows direct comparisons of metal availability in plastics with metal availability in environmental solids in order to evaluate the overall impacts of plastics in metal risk assessments. [ABSTRACT FROM AUTHOR]

The accurate and rapid detection of antibiotics and heavy-metal-based toxic oxo-anions in water media employing coordination polymers (CPs) as luminescent probes has attracted a lot of attention. Three new Cd(II)-based ternary CPs derived from first-presented L ligands, including [Cd(DCTP)(L)(OH)]n (1), [Cd(TBTA)(L)(OH)]n (2), and [Cd(NPHT)(L)(H2O)]n (3) (L = 2-((1H-imidazol-1-yl)methyl)-5,6-dimethyl-1H-benzo[d]imidazole, H2DCTP = 2,5-dichloroterephthalic acid, H2TBTA = tetrabromoterephthalic acid and H2NPHT = 3-nitrophthalic acid), were successfully assembled and characterized. 1 and 2 show 2D hcb layers, which can be further extended into a 3D supramolecular framework via classic hydrogen bonding interactions. 3 features a 1D double chain that ultimately spreads into a 2D network through weak hydrogen bonding interactions. With the advantages of high stability and excellent luminescent properties, the three CPs display high sensitivity, selectivity, and good anti-interference for the sensing of pefloxacin (PEF) and Cr2O72− ions (LOD values toward PEF: 3.82 × 10−7 mol L−1 for 1, 4.06 × 10−7 mol L−1 for 2, and 1.36 × 10−8 mol L−1 for 3, and toward Cr2O72− ions: 5.97 × 10−7 mol L−1 for 1, 5.87 × 10−7 mol L−1 for 2, and 8.21 × 10−8 mol L−1 for 3). These CPs are the first examples of bifunctional luminescent sensors to detect PEF and Cr2O72− in aqueous solutions. The luminescence quenching mechanisms are explored in detail. [ABSTRACT FROM AUTHOR]

Simple Summary: Anthropogenic pollution poses a major threat to aquatic ecosystems, which can lead to their degradation. The accumulation and toxicity of metals and trace elements in fish leads to physiological and chemical changes in the fish body. In this study, we investigated the effects of bioaccumulation of metals and trace elements on freshwater fish fatty acid profiles at two different sites before and after the discharge of untreated municipal wastewater in two fish species with different diet habits. Although the concentrations of toxic elements were below the maximum levels proposed by the EU and the Republic of Serbia, this study showed statistically significant correlations between the presence of certain elements and the fatty acid (FA) profile in fish muscle. Lower concentrations of polyunsaturated FA in fish sampled after the discharge of untreated municipal wastewater were detected. In this study, the concentrations of metals and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined in the muscle tissue of adult roach and white bream at two different sites in the Belgrade section of the Danube. Twenty-six fatty acids, consisting of nine saturated FA (SFAs), seven monosaturated FA (MUFAs) and ten polysaturated FA (PUFAs), were identified. The analysis of the concentration of metals and trace elements of the roach and white bream showed species-specific differences in their bioaccumulation. Four of all elements analyzed (As, Hg, Ni and Pb) correlated significantly with the changes in FA profiles in fish from both sampling sites, with the exception of Cu, which correlated with the FA profile at the site before, and Zn, whose concentration influenced the FA profile at the site after wastewater discharges. The lower PUFA content in the fish from a site under higher environment pressure could indicate that the fish are stressed. The results suggest that changes in lipid composition may be one of the protective mechanisms of cells to cope with anthropogenic stressors. [ABSTRACT FROM AUTHOR]

To determine the sources and pathways of lead (Pb) and zinc (Zn) in river sediments contaminated with metals from mining and smelting activities, metal concentrations and Pb and Zn isotope ratios were measured in river water and sediment, and potential metal contaminant samples (imported Zn concentrates, smelting wastes, soils around the smelter, mine ores, and riverside tailings). Zn and cadmium (Cd) concentrations in river water and sediment samples were 30- and 11–25-fold higher, respectively, near the smelter than upstream, while a 6-fold increase in sediment Pb concentrations was detected over the same region. Sediment samples near the smelter (207Pb/206Pb = 0.8638 and 208Pb/206Pb = 2.0960) were observed to have a different Pb isotopic composition from upstream of the smelter (207Pb/206Pb = 0.8322 and 208Pb/206Pb = 2.0502), with δ66Zn values increasing from –0.01 to 0.82‰. Analysis of Pb and Zn isotopes and concentrations revealed that dust-contaminated soils were a major Pb source, and baseline sediments were found to be contaminated by regional mining tailings. For Zn in sediments, the main Zn sources were groundwater-derived Zn (δ66Zn = 1.02 ± 0.43‰, n = 4), dust-contaminated soils (δ66Zn = –0.18 ± 0.08‰, n = 3), and tailings-contaminated sediments (δ66Zn = 0.01 ± 0.07‰, n = 10). Endmember mixing model results showed that dust-contaminated soils contributed 78% and 64% of sediment Pb and Zn, respectively, within 2 km of the Zn smelter, decreasing to negligible levels after 47.1 km downstream. Downstream of the smelter, groundwater-derived Zn contributed 54% of sediment Zn, whereas tailings contaminated sediments contributed 70% and 25% of Pb and Zn, respectively. [ABSTRACT FROM AUTHOR]

Physical and chemical trace metal speciation are important for our understanding of metal cycling and potential toxicity to marine life. Trace metals can behave differently in diffusion processes or particle-solution interactions and have different bioavailabilities depending on their physical and chemical forms, which often depend on redox conditions. Here we investigated dissolved (< 0.2 µm) and soluble (< 0.02 µm) concentrations of Mn, Co, Ni, Fe, Cu, V, Mo, U, Cd, and As in oxic and suboxic deep-sea sediments of the central equatorial Pacific Ocean. Vanadium, Mo, U, As, and Cd showed no significant concentration differences between their dissolved and soluble forms, suggesting that they are present as inorganic ionic species or organic complexes in the truly dissolved or small colloidal fraction. In contrast, the colloidal fraction (> 0.02 µm < 0.2 µm) of Mn, Co, Ni, and Cu increased with depth in oxic pore waters and Fe had the largest but variable colloidal pool. Soluble Mn, Co, and Ni were released in the uppermost 2-4 cm in the sediment because of reductive dissolution. The increasing colloidal fraction with depth suggests a decrease in the concentration of small organic ligands with depth, that are abundant in the surface sediment pore waters, and instead an increasing importance of larger (> 0.02 µm) inorganic nanoparticles and colloids such as Mn and Fe (oxyhydr)oxides that control Mn, Fe, and Co cycling at depths > 10 cm. The distribution of Ni and Cu cannot be exclusively explained by inorganic nanoparticles and a shift from low to larger high molecular weight organic ligands might occur. These findings provide new insights into trace metal distributions in the dissolved phase, highlighting the diversity of metal complexes and the need to incorporate these in future calculations of benthic metal fluxes and ecotoxicity assessments, especially in oxic pore waters. [ABSTRACT FROM AUTHOR]

High concentration of trace elements in groundwater poses more health risks to humans by drinking groundwater and dermal contact. This work aimed to assess the trace element concentration in groundwater, water quality for drinking purposes, and its effect on human health upon prolonged consumption. The study was carried out in the gneissic terrain of Perambalur District, Tamil Nadu, India, where groundwater is used mainly for drinking, agricultural, and domestic purposes. Hydrochemistry, water quality, and health risk assessments of trace elements from 44 groundwater samples for pre- and post-monsoon were determined by drinking water quality, hazard quotient, hazard index, and carcinogenic risk. The dominance of trace elements in groundwater was in the order of Zn > Fe > Cu > Ni > Te > Pb > Co. Ni and Co are released more during the post-monsoon, and Zn, Fe, Cu, and Pb concentration during the pre-monsoon. The dominant type of groundwater was Ca-HCO3 and mixed Ca–Mg–Cl type. The dissolution of fissile hornblende biotite gneissic rock dissolves more trace elements to groundwater than charnockite rock. The correlation matrix indicates that major ion and trace elements were positively good in groundwater during the pre-monsoon and post-monsoon 2018. The principal component analysis suggests that the weathering of rocks, rainwater recharge, and evaporation processes controlled the hydrochemistry of trace and major ions. The concentration of Pb, Ni, and Cd elements exceeded the permissible limit of BIS and WHO; these elements are unsuitable for drinking. The trace element concentration in groundwater was good for drinking and irrigation in the study area, except in a few wells. The hazard quotient and hazard index were computed, which revealed that non-carcinogenic risk to human health by drinking groundwater was more of a problem for children than adults. This study will help prevent children from health risks of trace elements. [ABSTRACT FROM AUTHOR]

For the first time, composites of metal-organic framework MOF-5 and conjugated polymer polyaniline (PANI), (MOF-5/PANI), prepared using PANI in its conducting (emeraldine salt, ES) or nonconducting form (emeraldine base, EB) at various MOF-5 and PANI mass ratios, were evaluated as electrode materials for the electrochemical detection of cadmium (Cd2+) and lead (Pb2+) ions in aqueous solutions. Testing of individual components of composites, PANI-ES, PANI-EB, and MOF-5, was also performed for comparison. Materials are characterized by Raman spectroscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS), and their electrochemical behavior was discussed in terms of their zeta potential, structural, morphology, and textural properties. All examined composites showed high electrocatalytic activity for the oxidation of Cd and Pb to Cd2+ and Pb2+, respectively. The MOF/EB-1 composite (71.0 wt.% MOF-5) gave the highest oxidation currents during both individual and simultaneous detection of two heavy metal ions. Current densities recorded with MOF/EB-1 were also higher than those of its individual components, reflecting the synergistic effect where MOF-5 offers high surface area for two heavy metals adsorption and PANI offers a network for electron transfer during metals' subsequent oxidation. Limits of detection using MOF/EB-1 electrode for Cd2+ and Pb2+ sensing were found to be as low as 0.077 ppm and 0.033 ppm, respectively. Moreover, the well-defined and intense peaks of Cd oxidation to Cd2+ and somewhat lower peaks of Pb oxidation to Pb2+ were observed at voltammograms obtained for the Danube River as a real sample with no pretreatment, which implies that herein tested MOF-5/PANI electrodes could be used as electrochemical sensors for the detection of heavy metal ions in the real water samples. [ABSTRACT FROM AUTHOR]

Eleven plant extracts from the seeds and rhizomes of spices cultivated in Transylvania were investigated. To evaluate seeds and rhizomes nutritional profiles, several parameters were analyzed including metals, amino acids, polyphenols, flavonoids, and antioxidant capacity. The antioxidant activity, polyphenols, and flavonoids were determined using UV-Vis analytical methods. From investigated seeds and rhizomes, the most pronounced antioxidant character and the highest concentration of polyphenols were achieved in nutmeg seeds, allspice seeds, and ginger rhizomes. The highest flavonoid content was identified in turmeric rhizome and dill seeds. For the free amino acids quantification, a GC-MS analytical method using the 15N-glycine as internal standard was used. 16 amino acids were determined in the analyzed samples, and ginger rhizome and oregano seeds proved to have the highest content of essential amino acids. The trace metals were detected using inductively coupled plasma – optical emission spectrometry (ICP-OES). Essential trace elements (Cr, Mn, Co, Ni, Cu, and Zn) and toxic trace elements (As, Cd, and Pb) were determined in the samples. From essential trace elements, Mn and Zn were quantified in higher concentrations; for toxic elements As and Cd were found in the studied herbs. The findings indicate that the studied herbs parts may be valuable sources of compounds with bioactive properties. [ABSTRACT FROM AUTHOR]

Ediacaran to Early Cambrian sequences are well preserved in several synclines within the Lesser Himalaya. We have conducted multi-proxy geochemical and stable isotopic studies on carbonaceous sediments of the basal Tal Group to decipher redox conditions of the Earliest Cambrian Ocean. Organic matter is immature, predominantly aliphatic and likely derived from marine phytoplankton. The S/C(organic) ratios above 0.4; strong enrichment of redox-sensitive trace elements V, Mo, U and Cd; higher DOPT, U/Th, V/Sc, Mo/Sc and V/(V+Ni) ratios; V/Al–U/Al–Mo/Al systematics and U–Mo enrichment factors indicate anoxic to euxinic conditions of deposition. Large variations (5–7‰) in δ13C likely reflect spatial heterogeneity or vertical gradient in DIC compositions of the Early Cambrian Ocean, and possibly capture the part of Basal Cambrian negative Carbon isotope Excursion (BACE). Finely disseminated texture of pyrite framboids with sizes mostly below 10 µm suggest sulfide reduction within the water column in an open system. Isotopically heavy δ34S values (+4.5 to +22.8‰) overlap with the δ34Ssulfate of contemporary Fortunian ocean (+10 to +40‰), suggesting sulfidic conditions and small size of the sulfate reservoir. Whereas the REE+Y proxies of the same set of samples show seawater-like patterns, with strong HREE enrichment, positive Y and La anomalies and negative Ce anomaly (avg. Ce/Ce* = 0.78), indicating REE uptake by phytoplankton from an oxidized-euphotic surface zone. The combined geochemical and isotopic data suggest a strongly stratified ocean with sulfidic bottom water and oxidized surface water. Episodic shoaling of anoxic deep water onto the surface possibly caused the extinction of benthic Ediacaran fauna, and the surface oxidized zone likely provided the niche for further metazoan radiation. [ABSTRACT FROM AUTHOR]

The possibility of applying a thermodynamic approach to calculate the elements’ chemical species and thus to more effectively assess the water quality is demonstrated. Iskar river and its three tributaries Lesnovska, Kakach and Blato rivers within Sofia Municipality were chosen as a case study. Experimental field and laboratory studies were done to create an input database for thermodynamic calculations. The obtained analytical data revealed high concentrations of PO43-,NH4+ and NO2- in all studied water samples, which is an indicator for serious domestic pollution. The water was pure in terms of Fe, Co, Ni, Cu, Zn and Cd. Al, Pb and Mn exceeded the maximum allowed concentrations in the water of Iskar river after Sofia city, and along the entire flow of Lesnovska river. The thermodynamically calculated chemical species showed that Na, K, Mg, Ca, NO2-, NO3- and NH4+ exist mainly as free ions. The presence of dissolved ammonia was calculated for all sample stations, which is a serious problem for aquatic animals, especially for fish. PO43- showed a great variety of forms depending on pH. Among the trace metals (Al, Pb and Mn), Pb is potentially the riskiest element for plants, as its dominant organometalic species are easily accumulated by them. Free ions of Mn dominate, which is dangerous for aquatic fauna as Mn2+ ions easily interact with ligands of organic compounds found in the bloodstream and/or within organs. Regarding Al, the dominant hydroxy species are a prerequisite for the precipitation of Al(OH)3 and thus, for the self-purification of waters. [ABSTRACT FROM AUTHOR]

Consumption of cosmetic products in daily life in order to improve skin quality or appearance is becoming quite common. Over time, it may expose consumers to skin problems and effects caused by the absorption of chemical elements. Clean cosmetic production is important for our health. However, heavy metals can be found as impurities in raw materials or as by-products of the cosmetic production process. Women's ingestion and exposure to organic and inorganic contaminants in cosmetics through dermal absorption, due to reasons such as personal habits and characteristics of the living environment, may contribute to carcinogenic risks following daily dietary exposure. NCS ZC 81002b (Human Hair) was performed as a certified reference material in method validation. This work was conducted to evaluate element concentrations of selected elements (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Hg, Cd and Pb) in 3 different brands of children's cosmetic products such as bright and colorful 22 eye shadows (7 different colour) 4 lipsticks (3 different colour) and 4 nail polishes (3 different colour) used by children in Turkey. The sample solutions were analyzed with the inductively coupled plasma mass spectrometry (ICP-MS) technique after the microwave digestion system. Consequently, the highest concentration of Al used as pigment was found in the eye shadow, lipstick and nail polish samples for the 3 brands, while the Se concentrations were the lowest in lipstick samples. The results of As, Cd, Hg, Pb, which are restricted or banned for use in cosmetic products in most countries, are below the limits set by the Food and Drug Administration (FDA) and Health Canada Product Safety Laboratory (PSL). [ABSTRACT FROM AUTHOR]

The current study investigated wild plant resources and health risk assessment along with northern Pakistan's mafic and ultramafic regions. Ethnobotanical data was collected through field visits and semi-structured questionnaire surveys conducted from local inhabitants and healers. Six potentially toxic elements (PTEs) such as lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), manganese (Mn), and zinc (Zn) were extracted with acids and analyzed using atomic absorption spectrophotometer (AAS, Perkin Elmer-7000) in nine selected wild medicinal plants. Contamination factor (CF), pollution load index (PLI), estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were used to determine the health risk assessment of the studied medicinal plants. The results showed that the selected medicinal plants were used for the treatments of cough, joint swelling, cardiovascular disorders, toothaches, diabetes, and skin pimples by the local inhabitants due to their low-cost and easy accessibility. The concentrations of Pb (3.4–53 mg kg–1), Cd (0.03–0.39 mg kg–1), Ni (17.5–82 mg kg–1), Cr (29–315 mg kg–1), Mn (20–142 mg kg–1), and Zn (7.4–64 mg kg–1) in the studied medicinal plants were found above the safe limits (except Zn) set by WHO/FAO/USEPA (1984/2010). The Pb contamination factor was significantly (p < 0.05) higher in A. modesta (7.84) and D. viscosa (6.81), and Cd contamination factor was significantly higher in C. officinalis (26.67), followed by A. modesta (8.0) mg kg–1. Based on PTE concentrations, the studied plants are considered not suitable for human consumption purposes. Pollution load index values for A. modesta, A. barbadensis, A. caudatus, A. indica, C. procera (2.93), D. viscosa (2.79), and C. officinalis (2.83), R. hastatus (3.12), and Z. armatum were observed as 1.00, 2.80, 2.29, 2.29, 2.93, 2.79, 2.83, 3.12 and 2.19, respectively. Hazard index values were in order of R. hastatus (1.32 × 10–1) ˃ C. procera (1.21 × 10–1) ˃ D. viscosa (1.10 × 10–1) ˃ A. caudatus (9.11 × 10–2) ˃ A. barbadensis (8.66 × 10–2) ˃ Z. armatum (7.99 × 10–2) ˃ A. indica (6.87 × 10–2) ˃ A. modesta (5.6 × 10–2) ˃ C. officinalis (5.42 × 10–2). The health risk index values suggested that consumption of these plants individually or in combination would cause severe health problems in the consumers. Pearson's correlation results showed a significant correlation (p ≤ 0.001) between Zn and Mn in the studied medicinal plants. The current study suggests that wild medicinal plants should be adequately addressed for PTEs and other carcinogenic pollutants before their uses in the study area. Open dumping of mining waste should be banned and eco-friendly technology like organic amendments application should be used to mitigate PTEs in the study area. [ABSTRACT FROM AUTHOR]

As an alternative wood source for biochar and a cost-effective renewable energy source, sustainable biomass production based on fast-growing willows irrigated with treated wastewater has been explored. Salix alba L. and Salix viminalis L. were selected for assessment of their potentially high woody biomass productivity and phytoremediation efficiency when irrigated with greywater treated by floating treatment wetlands. Both Salix species produced significantly (p < 0.05) high woody biomass in the second harvest, with a significantly higher fresh woody biomass weight with higher water content (53%) for S. viminalis compared to S. alba. The dry biomass weight of S. alba was greater than of S. viminalis at the first harvest. The element accumulations in substrates changed significantly after irrigation, with greywater compared to the raw substrate following this order: Mg > Fe > Al > Cr > Mn > Cd > Cu > B. Element concentrations accumulated in twigs of S. alba following this order: Ca > Mg > Na > Mn > Zn > Fe > Al > Cd > Cu > Cr > Ni > B, but for S. viminalis the order was Ca > Mg > Mn > Zn > Na > Fe > Al > Cd > Cu > Ni > Cr > B. The accumulations of Al, B, Ca, Fe, Mg, Mn, and Ni were significantly greater in S. alba leaves compared to their twigs, which showed significantly high accumulations of Na and Zn. The accumulations of Al, B, Ca, Fe, Mg, Mn, and Na were significantly greater in S. viminalis leaves compared to their twigs. [ABSTRACT FROM AUTHOR]

The ecological status of Algeciras Bay (South-west Europe), highly influenced by anthropogenic activities, was assessed by monitoring Zn, Cd, Pb, and Cu in water and sediment samples. Total contents and metal fractions with different availabilities and their spatial-seasonal distribution were determined. The trend in water and sediment contents were Zn > Pb ≈ Cu > Cd, without significant seasonal variations. Sites 3 and 4, closest to industrial activities, had the highest metal concentrations, mainly in sediments. Cd showed low partition coefficient in water, indicating higher bioavailability. Total metal content in sediments exceeded the threshold effect level for Cu and were close to Pb. The BCR procedure revealed the highest availabilities for Cd and Pb, due to its higher content in exchangeable and reducible fractions. Higher Pb levels (21.4 ± 5.1 mg/kg) were found in sediments of this bay compared with other ecosystems. Pollution indexes for sediment quality revealed that site 3 was the most polluted (CF = 7.12 and Igeo = 2.25). For an integrative study of the ecological status of this significant bay, these results have been complemented with the metal evaluation in benthic and benthopelagic fish tissues in Ecological status of Algeciras Bay, in a highly anthropised area in south-west Europe, through metal assessment—Part II: Biotic samples. [ABSTRACT FROM AUTHOR]

Trace elements in hot-spring waters are indicators for tracing hydrochemical processes, such as the deep circulation of geothermal water, the degree of water–rock interaction, redox reactions, the contamination of shallow water by thermal water, etc. In this study, 74 hot springs in the Xianshuihe–Xiaojiang Fault Zone (XSHF-XJF) were chosen for an investigation of the geochemical characteristics of trace elements using classic geochemical tools and multivariate statistical analysis. The results indicated (1) the hot-spring waters were mainly derived from atmospheric precipitation as indicated by δD and δ18O values that generally increased with decreasing elevations; (2) the high concentrations of B, As, Fe, and Mn in the waters, as well as the values of the Water Quality Index (WQI), indicated that the water quality was spatially heterogeneous and the hot-spring waters are not entirely suitable for drinking; and (3) B/Cl ratios showed that hot springs have different reservoir sources in the XSHF and XJF, respectively. The leaching of surrounding rock during water circulation contributed predominantly to the trace elements of the study's waters. Diversity of lithology was the main factor affecting their concentrations. In addition, deep circulation controlled by the fault could influence trace-element enrichment. Our results offer a guide for the exploration and use of geothermal resources. [ABSTRACT FROM AUTHOR]

Pacific sardine (Sardinops sagax) in the northwest Pacific Ocean (NPO) not only preserve the equilibrium of the NPO food chain, but also serve as a source of nutrition for humans. In order to evaluate the levels of various elements in S. sagax, we collected specimens from NWP waters and ascertained the quantities of four macronutrients, nine essential trace elements, and twelve non-essential trace elements. The factors (fatness, sex, sexual maturity, body length, body weight, and age) influencing the concentration were investigated, and the correlations of trace elements were examined. Additionally, the Estimated Daily Intake (EDI) approach and the Target Hazard Quotient (THQ) methodology were used to assess contamination levels and associated consumption risks. The results revealed that the macronutrient content (54–10,500 mg kg−1) was higher than the necessary trace elements (0–488 mg kg−1) and the non-essential trace elements (0–448 mg kg−1), and most of the elements showed positive correlation with each other. Almost all of the element concentrations were below the maximum permitted levels (MPLs) recommended by the FAO/WHO, except for As and Cd. The factors, including fatness, sexual maturity, body length, body weight, and age, showed a negative correlation with most of the trace elements. The outcomes of the stepwise regression analysis showed that sex and stage of sexual maturation were the principal biological factors influencing elemental content. The risk assessment and standard dietary intake levels indicated that the potential health issues associated with the consumption of S. sagax were negligible. [ABSTRACT FROM AUTHOR]

g-C3N4/ZnxCd(1-x)S composites were synthesized by a simple hydrothermal method. The composites were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, infrared spectroscopy, and electron micro-projective microscopy. According to the performance of ZnxCd(1-x)S for the photocatalytic degradation of norfloxacin under visible light in water, the best stoichiometric number of x was 0.5. The best photolytic norfloxacin degradation rate of g-C3N4/ZnxCd(1-x)S composites was 89.8%, which was obtained when the dosage ratio of g-C3N4 to ZnxCd(1-x)S was 1:1. The experiment was conducted to investigate the effect of pH on the catalyst to obtain the optimal NORF degradation environment pH in the range of 7 ± 0.3; by simulating the anions that may be contained in the actual environmental water, the results showed that the catalyst has a certain effect on the degradation of NORF when the water contains NO3−, Cl− and HCO3−. In addition, this study also obtained that the main active substances produced by the catalyst during degradation were electron–hole pairs by adding different trapping agents in the NORF removal experiments; and the catalyst was able to achieve a degradation rate of 86.1% after four cycles of the experiments, which proved that it had good stability. [ABSTRACT FROM AUTHOR]

Several million tons of coal are extracted which discharge the contaminated mineral water into the environment in the coal mines located in the Korba basin (Chhattisgarh, India) chosen as the study area. The aim of this work is to describe: (i) the physico‐chemical characteristics (pH, EC, TDS, DO, RP, CC (carbonate carbon), OC (organic carbon) F−, Cl−, NO3−, SO42−, SiO44−, PO43−, Na+, K+, Mg2+, Ca2+, Al, As, Sb, Fe, Mn, Zn, Cd, Pb, and Hg) of the coal mine water samples, (ii) spatial, seasonal (i.e. PrM (pre‐monsoon), M (monsoon) and PtM (post monsoon) and temporal (over the period of 2012–2017) variations, (iii) sources of contaminants from fourteen coal mines, (iv) suitability of the water for drinking and other uses, and (v) health impact of the mine water in view of developing remedial approaches. The mine water is neutral in nature with high TDS (total dissolved solid) values ranging from 620 to 13711 mg L−1 due to mainly high carbon content. The concertation of all species lies between 519–11432 mg L−1 with maximum value of OC. The most dominating species were OC, CC, Cl−, NO3−, SO42−, Na, and Ca. Species, that is, F−, OC, Al, Fe, As, Sb, Cd, Pb, and Hg occurred beyond their limits. Their higher concentration in the PtM is observed. Water quality index (WQI) values ranged from 17.52 to 95.68 in the PtM period. 42.85%, 21.42%, and 7.14% of water samples represent "excellent water", "good water" and "poor water" respectively in the PtM period. In addition, the fertilizer and trace element concentrations in the water samples were compared with the limit values determined for usability as drinking water. Accordingly, it was concluded that it is not suitable for use as drinking water in terms of TDS, F−, and NO3− concentrations. In addition, AsT (total arsenic), F− and NO3− pollutants were detected in the water samples, and it was observed that F− and NO3− ions did not have a carcinogenic effect. A health risk assessment of As has been made, and it is found that adults and children have a low risk of developing cancer from the exposure. However, arsenic has high non‐carcinogenic and potentially harmful effects. [ABSTRACT FROM AUTHOR]

Comprehending the characteristics of heavy metal contamination within mine tailings and its ramifications on ecological and human well‐being holds paramount importance in formulating effective preventive and ameliorative strategies. This investigation evaluates the health hazards posed by the tailings originating from the Angoran lead‐zinc mine situated in Zanjan province, Iran. The mine generates two distinct types of tailings: hot filter cake (referred to as cobalt cake or S2) and cold filter cake (nickel cake or S1). Twenty subsamples were procured from each type of tailing and subjected to analysis at the pollution research laboratory of University of Zanjan. The quantification of lead (Pb), zinc (Zn), arsenic (As), cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), mercury (Hg), manganese (Mn), and antimony (Sb) concentrations was accomplished through the utilization of inductively coupled plasma mass spectrometry (ICP‐MS). Carcinogenic and non‐carcinogenic risk assessment indices were computed. Moreover, the limits of detection (LOD) and quantification (LOQ) for the measurements were established using blank solutions prepared as samples for assessment. The Hazard Index (HI) surpassed unity for Pb, Zn, Cd, As, Hg, and Mn in both types of tailings, signifying non‐carcinogenic risk exposure for both children and adults. Furthermore, the HI for Pb and As also exceeded unity for adults. Consequently, both age groups were subject to non‐carcinogenic hazards, with children encountering notably elevated risks. The chief pathways for exposure to heavy metals and the ensuing non‐carcinogenic risks encompassed ingestion, inhalation, and dermal contact. The cumulative risk threshold for carcinogenic outcomes, in accordance with USEPA standards, ranged between 1.00E‐04 and 1.00E‐06. In this inquiry, the overall risk for children associated with tailing S1 and S2 amounted to 2.39E‐03 and 5.00E‐03, respectively, markedly surpassing the acceptable threshold. Furthermore, the cumulative risk for adults pertaining to tailing S1 and S2 stood at 1.27E‐03 and 4.68E‐03, respectively, indicating the presence of carcinogenic perils in the adult demographic. [ABSTRACT FROM AUTHOR]

In this study, synchronous fluorescence spectroscopy and Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy analyses were applied to investigate binding characteristics between dissolved organic matter (DOM) and multiple Cu2+ and Cd2+ through quenching titration experiments. The results suggested that the binding constant (lgKM for Cu2+ and Cd2+ ranged from 4.75~5.18 and 3.71~4.12, respectively, indicating the stronger binding affinity with Cu2+ than Cd2+. The binding sequence to DOM for Cu2+ both were 430 nm~500 nm>330 nm~420 nm under 0 and 100 µmol/L Cd2+, and the lgKM for Cu2+ ranged from 4.56~4.95 in the presence of Cd2+. The comparative result showed that the presence of Cd2+ had no effect on the binding sequence, but attenuate the binding affinity between DOM and Cu2+. FTIR results showed that, the structural changes of DOM upon interaction with Cu22+ under 0 and 100 µmol/L Cd2+ followed the order of phenolic C-O>amide N-H>amide C=O>carboxyl C=O>aromatic C-H>polysaccharides C-O and amide N-H> amide C=O>phenolic C-O>aromatic C-H>polysaccharides C-O, respectively. The phenolic C-O interacted with Cd2+ and then affect the interaction between Cu2+ and DOM functional groups, such as phenolic C-O and carboxyl C=O. The bioavailability and ecological risk of heavy metals should be pay close attention under co-existence of heavy metals in water environments. [ABSTRACT FROM AUTHOR]

Hydropsyche and Arctopsyche are filter-feeding caddisflies (Order: Trichoptera; Family: Hydropsychidae) that are commonly used to monitor metal exposures in rivers. While tissue residue concentrations provide important bioaccumulation data regarding metal bioavailability, they do not provide information regarding the mechanisms of uptake and loss, or exposure history. This study examined the physiological processes that control Cu and Cd uptake and loss using a biokinetic bioaccumulation model. Larvae of each taxon were experimentally exposed to either water or food enriched with stable isotopes (65Cu and 106Cd). Dissolved Cu uptake (ku) was similar between species (2.6–3.4 L-1g 1d-1), but Cd uptake was 3-fold higher in Hydropsyche than Arctopsyche (1.85 L-1g 1d-1 and 0.60 L-1g 1d-1, respectively). Cu and Cd efflux rates (ke) were relatively fast (0.14 d-1–0.24 d-1) in both species, and may explain, in part, their metal tolerance to mine-impacted rivers. Food ingestion rates (IR), assimilation efficiency (AE) of 65Cu and 106Cd from laboratory diets were also derived and used in a biodynamic model to quantify the relative contribution of dissolved and dietary exposure routes. Results from the biodynamic model were compared to tissue concentrations observed in a long-term field study and indicated that because dissolved Cu and Cd exposures accounted for less than 20% of body concentrations of either taxon, dietary exposure was the predominant metal pathway. An estimation of exposure history was determined using the model to predict steady state concentrations. Under constant exposure conditions (dissolved plus diet), steady state concentrations were reached in less than 30 days, an outcome largely influenced by rapid efflux (ke). [ABSTRACT FROM AUTHOR]

At present, the rational design and facile synthesis of highly active and low-cost photocatalysts are still facing great challenges. Herein, a series of Zn0.5Cd0.5S/NiS (x mol%) composite photocatalysts have been synthesized via a simple and mild one-pot hydrothermal method. Compared with pure Zn0.5Cd0.5S, the NiS-loaded samples exhibit enhanced photocatalytic hydrogen generation performance, in which the Zn0.5Cd0.5S/NiS-5% sample has the highest H2 production rate of 10 855 ± 461 μmol h−1 g−1 with a quantum yield of 11.82% at 365 nm, which is almost 6.3 times higher than that of pristine Zn0.5Cd0.5S. The high activity of the Zn0.5Cd0.5S/NiS nanosheets may be attributed to their distinct nanostructure, including a short transfer distance of photoinduced charge carriers, a large number of unsaturated surface atoms, and a large surface area. Moreover, the added NiS nanoparticles served as an effective cocatalyst to promote photoinduced electron transfer and enhance the surface kinetics of H2 evolution. Our work provides a simple and effective route for the preparation of sulphur-based photocatalysts, which can significantly improve the efficiency of hydrogen production from water. [ABSTRACT FROM AUTHOR]

Data on the content of dissolved trace elements (P, Si, Li, Rb, Cs, Be, Sr, Ba, Mn, Fe, Co, Ni, Cu, Zn, Cd, Tl, Pb, Al, Ga, Y, Ti, Zr, Hf, Th, U, rare earth elements, F, B, Ge, V, As, Sb, Cr, Se, Mo, and W) in the river runoff from the Russian Arctic sea watersheds were systematized and generalized. There is a tendency for the decrease in the trace element concentrations in the direction from west to east for the considered Arctic watersheds (the White, Pechora, Kara, Laptev, and East Siberian seas). It was shown that the concentrations of dissolved trace elements in the river runoff from the Russian Arctic sea watersheds are in general consistent with modern estimates of the average composition of the global river runoff. [ABSTRACT FROM AUTHOR]

Studying competitive effects of microbial and light-induced degradation of dissolved organic matter (DOM) is crucially important for understanding the factors controlling aquatic carbon (C) transformation in boreal waters. However, studies addressing both DOM and trace element (TE) behavior are limited, which does not allow assessment of coupled C – TE (including macro- and micronutrients and toxicants) biogeochemical cycles in these environmentally important settings. Here we conducted a seasonally-resolved assessment on the degree of DOM and related major and TE transformation under biotic activity and sunlight using conventional incubations of humic surface waters from the European subarctic. We studied bio- and photodegradation over 2–3 weeks in an ombrotrophic peatbog continuum (subsurface water from piezometer – small peatland pool – outlet stream) during July, and in three horizons (0.5, 5 and 10 m) of deep (30 m), a stratified forest lake from the same region during June, August and September. Along the bog water continuum in July, biodegradation rate was the highest in subsurface waters collected via piezometer and the lowest in the acidic peatland pool (0.17 to 0.03 mg C L-1 d-1, respectively). Photodegradation was similar for piezometrically collected subsurface waters and the stream (about 0.3 mg C L-1 d-1), but was not detectable in the peatland pool. The waters of forest lake exhibited a strong seasonal effect of biodegradation, which was the highest in October and the lowest in June (0.04 and 0.02 mg C L-1 d-1, respectively). The photodegradation of DOM from the forest lake was observed only in June and August (0.19 and 0.07 mg C L-1 d-1, respectively). Biodegradation was capable of removing between 1 and 7 % of initial DOC, being the highest in the forest lake in October and in peatland pool in summer. The photolysis was capable of degrading a much higher proportion of the initial DOC (10–25 %), especially in the forest lake during June and the bog stream during July. The change of optical parameters confirmed the highest photodegradation occurs in June (Arctic summer) and demonstrates a decrease of chromophoric (aromatic) compounds during incubation, whereas biodegradation acted preferentially on aliphatic, low molecular weight compounds. Only a few trace metals were sizably affected by both photo- and biodegradation of DOM (Fe, Al, Ti, Nb and light REE), whereas V, Mn, Co, Cu and Ba were affected solely by biodegradation. Typical values of TE removal over a 2-week period of incubation ranged from 1 to 10 %. These effects were mostly pronounced in the less acidic forest lake compared to the bog waters. A likely mechanism of TE removal was their coprecipitation with coagulating Fe(III) hydroxides. When averaged across sites and seasons, DOM biodegradation and photodegradation processes could remove 5.3 and 10.8 mg C L-1 y-1, respectively. Compared to typical CO2 emissions from inland waters of the region, biodegradation of DOM can provide the totality of C-CO2 evasion from lake water surfaces whereas bio- and photodegradation are not sufficient to explain the observed fluxes in bog water continuum. Overall, these results demonstrated strong spatial and seasonal variability in DOM and TE complexes bio- and photodegradation, which was poorly accessed until now, and call for the need of a systematic assessment of both processes across seasons with high spatial resolution. [ABSTRACT FROM AUTHOR]

The escalating presence of heavy metals (HMs) in the Panjkora River water and their impact on fish pose a significant challenge to both the ecological community and human health. Consequently, a study was conducted with the primary aim of elucidating their influence on human health-related issues. To address this, the concentrations of heavy metals, including arsenic (As), cadmium (Cd), iron (Fe), manganese (Mn), lead (Pb), and zinc (Zn), in both water and the fish species Crossocheilus diplocheilus were investigated across various locations within the study area. The quantification of HMs concentration was carried out utilizing an atomic absorption spectrophotometer. The highest concentration in water was found as 0.060 mg/L for Pb and lowest for Fe, whereas the highest concentration in fish was 2.028 mg/kg for Pb and lowest for As. Human health risk associated with fish eating was evaluated by using health risk indices (HRI) for non-carcinogenic health risks and targeted cancer risk (TR) for carcinogenic health risks. The values of the health risk index (HRI) were found greater than 1 except Fe (0.0792), Zn (0.782), and Mn (0.541). The highest mean HRI > 1 was recorded for As (62.99), Cd (26.85), and Pb (10.56). This implies that fish consumption from river Panjkora is not safe up to some extent. Similarly, the TR value for As, Cd, and Pb was found 2.8 × 10 - 2 , 1.6 × 10 - 2 , 2.8 × 10 - 3 which showed cancer risk. There is a detected risk to human health associated with the consumption of fish from the Panjkora River. The government must implement adaptive measures to address this significant issue of water pollution in the study area. Additionally, there is a need for further extensive and prolonged research studies in this context. [ABSTRACT FROM AUTHOR]

Increasing illicit drug use is one of the main problems in most countries or societies. Monitoring heavy metals and trace elements in this vulnerable group seems to be necessary. Therefore, we assessed the urinary trace element and toxic metals/metalloids concentrations (Zinc (Zn), Iron (Fe), Copper (Cu), Chromium (Cr), Lead (Pb), Cadmium (Cd), Arsenic (As), Nickel (Ni), and Mercury (Hg)) in opium, tramadol, and cannabis users compared to healthy subjects. In this cross-sectional study, patients with substance use disorder (SUD) (n = 74) were divided into four groups: cannabis, tramadol, opium, and mixed (simultaneous use of more than one of the three studied substances), along with a healthy group (n = 60). Urine samples were prepared by dispersive liquid-liquid microextraction method so that heavy metals/metalloids could be measured by ICP-MS. The mean urinary concentration of Cu (48.15 vs. 25.45; 89.2%, p<0.001), Hg (1.3 vs. 0.10; 1200%, p < 0.001), and Zn (301.95 vs. 210; 43.8%, p < 0.001) was markedly lower among patients with SUD. The mean urinary concentration of other elements including As (1.9 vs. 4.1; 115.8%), Cd (0.1 vs. 1.10; 1000%), Cr (6.80 vs. 11.65; 71.3%), Ni (2.95 vs. 4.95; 67.8%), and Pb (1.5 vs. 7.9; 426.6%) were significantly higher among patients with SUD compared to healthy subjects. When sub-groups were compared, no significant differences were observed between their trace element levels (Kruskal-Wallis test, p > 0.05). This can be an indication that regardless of the type of drug, the levels of trace elements are changed with respect to healthy individuals. Our results showed that illicit drug use causes changes in urinary trace element/heavy metal/metalloid levels and highlights the need for monitoring heavy metals and trace elements in individuals with substance use disorder. Assessment of different elements in biological samples of drug dependents may be useful for implementing new prevention and treatment protocols. In case of changes in their levels, complementary recommendations, attention to diet, and periodic assessment of toxic metal levels within treatment programs will be needed. [ABSTRACT FROM AUTHOR]

This work provides a facile electrochemical method for simultaneous detection of Cd2+, Pb2+, and Cu2+, on the base of one-pot synthesis of triethanolamine (TEOA)-functionalized gold nanoparticle (AuNP)-metal–organic framework-graphene oxide nanocomposites (TEOA@AuNPs-GO-UiO-66-NH2). In this method, TEOA not only can act as a base for the deprotonation of 2-aminoterephthalic acid, leading to in situ synthesizing the UiO-66-NH2 on the GO nanosheets by a one-step hydrothermal method, but also can be used as a reductant reacted with HAuCl4 to form AuNPs, improving the conductivity of the composite by accelerating the electron transfer. Moreover, this composite can serve as an enrichment medium phase of heavy metal ions because of the interaction between metal cations and hydrophilic groups of TEOA, UiO-66-NH2, or GO, which have the synergic effect of enhancing the electrochemical signals. The morphology and structure information of TEOA@AuNPs-GO-UiO-66-NH2 composite were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FT-IR). Under the optimal conditions, the TEOA@AuNPs-GO-UiO-66-NH2-modified electrode was applied for individual and simultaneous electrochemical detection for the Cd2+, Pb2+, and Cu2+ in an acetic acid buffer solution with satisfactory linear range and significantly low limits of detection. This electrochemical sensor was successfully utilized for simultaneous detection of Cd2+, Pb2+, and Cu2+ in river water with great selectivity and accuracy, displaying great potential application in food safety and environmental monitoring. [ABSTRACT FROM AUTHOR]

As long-living apex predators, sharks tend to bioaccumulate trace metals through their diet. The distribution of Al, As, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, V, Zn and Hg in different tissues (muscle, liver, heart, gills and gonads) of large-size (58–390 cm) sharks, some of which rare, of the eastern Mediterranean Sea was studied. Trace metals analyses in samples originating from ten different Chondrichthyes species were performed by inductively coupled plasma–mass spectrometry (ICP-MS) and Cold Vapor Atomic Absorption Spectrometry (CVAAS) for Hg. Data on trace metal levels are for the first time reported herewith for the species O. ferox and H. nakamurai. Higher median concentrations of trace metals were generally determined in the liver. The concentrations of Hg, Cs and As in the muscle increased proportionally with body length. Statistically significant differences between sexes were recorded for Hg, Cr, Ni and As (p = 0.015) in the muscle tissues of P. glauca. Muscle tissue Hg concentrations exceeded the EU maximum limit (1 μg g−1 wet weight) in 67% of the individuals sampled, with the highest concentrations detected in O. ferox and S. zygaena, whereas regarding Pb (limit 0.30 μg g−1 ww), the corresponding percentage was 15%. Arsenic concentrations were also of concern in almost all shark tissues examined. [ABSTRACT FROM AUTHOR]

• Heavy metal concentrations in the SPM were high during the dry period than in the rains. • The volumetric levels of SPM depicted the influence of oceanic waters. • Calculated Toxic Risk Index indicated low toxic risk to the benthos living in the lagoon. • The mean –ERM- Quotient denoted 9% probability of toxicity to the biota. The present study aimed to evaluate multi-element concentrations (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr) in suspended particulate material (SPM) collected from Ensenada de La Paz (ELP) lagoon, Baja California Sur, Mexico in two different periods (September and May) to comprehend their origin, geochemical behavior, mass transfer and associated ecotoxicological risks. The 24 hr variation coefficient of volumetric SPM levels were found to be 51.7% in September and 40.5% in May, signifying the effects of oceanic waters. The calculated enrichment factor (EF) values for all the studied elements were of higher magnitude because of the high surface area and oxide nature of SPM, and in this study, Mo had the highest EF of 46.77 probably due to its origin from continental weathering. From the ecotoxicological perspective, the integrated toxic risk index revealed low toxic risk to the benthic community. However, the mean-ERM-Quotient calculated using the particulate concentrations of As, Cd, Cr, Cu, Ni, Pb indicated 9% probability of toxicity to biota. The comprehensive geochemical and ecotoxicological assessment of particulate metal concentrations in the ELP lagoon signify low to moderate contamination. [Display omitted] [ABSTRACT FROM AUTHOR]

The Nigerian oil sands represent the largest oil sand deposit in Africa, yet there is little published information on the distribution and potential health and ecological risks of trace elements in the oil resource. In the present study, we investigated the distribution pattern of 18 trace elements (including biophile and chalcophile elements) as well as the estimated risks associated with exposure to these elements. The results of the study indicated that Fe was the most abundant element, with a mean concentration of 22,131 mg/kg while Br had the lowest mean concentration of 48 mg/kg. The high occurrence of Fe and Ti suggested a possible occurrence of ilmenite (FeTiO3) in the oil sands. Source apportionment using positive matrix factorization showed that the possible sources of detected elements in the oil sands were geogenic, metal production, and crustal. The contamination factor, geo-accumulation index, modified degree of contamination, pollution load index, and Nemerow pollution index indicated that the oil sands are heavily polluted by the elements. Health risk assessment showed that children were relatively more susceptible to the potentially toxic elements in the oil sands principally via ingestion exposure route (HQ > 1E-04). Cancer risks from inhalation are unlikely due to CR < 1E-06 but ingestion and dermal contact pose severe risks (CR > 1E-04). The high concentrations of the elements pose serious threats due to the potential for atmospheric transport, bioaccessibility, and bioavailability. [ABSTRACT FROM AUTHOR]

As an unconventional natural gas resource, coalbed methane (CBM) development releases a large amount of CBM wells co-produced water. Geochemical characteristics of the co-produced water provide an essential foundation for the production dynamics of CBM reservoirs if the impacts of fracturing fluids and other aquifers can be ignored. In the Shizhuangnan Block of the southern Qins-hui Basin, constant and trace elements in CBM co-produced water from the wellheads were collected and determined, which is applied to assess water source, fracturing fluid effect, and CBM production. Based on principle component analysis and hierarchical clustering analysis, the water samples are divided into four categories. It suggests that different characteristics affected by water-rock interaction, reservoir environment, aquifer recharge, and hydraulic fracturing result in the various ratios of Na+/Cl−, alkalinity ( H C O 3 − + C O 3 2 − )/Cl− and other specific rules. Moreover, Cl− is selected as a dividing line for complete fracturing fluid flow back, associated with organic-bound chlorine complexes in the original coal seam water. Compared to constant elements, there is a significant correlation between Li and Sr concentrations and CBM productivity, so templates regarding trace elements can be used to distinguish various sources of the co-produced water. [ABSTRACT FROM AUTHOR]

ABSTRACT Many minerals within the subcontinental lithospheric mantle (SCLM) contain structurally bonded hydrogen (commonly referred to as 'water'), which significantly impacts their physical properties and associated geodynamic processes. Observations from different localities worldwide make understanding the behavior of hydrogen during partial melting and mantle metasomatism a contentious issue, as different localities reveal either melting or metasomatism as the controlling factor. To provide new insights, major elements, trace elements and water contents of peridotite xenoliths from three volcanoes of the Shuangliao Volcano Group in Northeast China were analyzed. Minerals display variations in major and trace elements, particularly in clinopyroxene. Most olivine contains no observable water, while orthopyroxene and clinopyroxene retained 14–157 and 46–351 μg/g of water, respectively. Samples were divided into three types according to clinopyroxene trace element patterns, namely, type 1: light rare earth elements (LREEs)-depleted samples; type 2: 'spoon-shaped' samples featuring slight enrichment of the most incompatible elements (La and Ce) and relative depletion of mid-rare earth element; and type 3: LREE-enriched samples. Combined with major element trends, the Shuangliao SCLM experienced varying degrees of partial melting and cryptic metasomatism. Different water contents in the Shuangliao SCLM are a combined result of melting and metasomatism: less metasomatized samples (LREE-depleted and 'spoon-shaped') preserved the control of water contents by partial melting, while strongly metasomatized samples (LREE-enriched), equilibrated at higher oxygen fugacity and temperature, display considerable post-melting modifications of water contents, possibly associated with Fe redox. These characteristics suggest that hydrous and oxidized melts/fluids likely released by the stagnant Pacific slab in the big mantle wedge have metasomatized the shallow SCLM beneath Shuangliao, which indicates the circulation of materials released by the stagnant slab throughout the upper mantle. [ABSTRACT FROM AUTHOR]

Sediment samples from the Săsar River and its main tributaries were analyzed for their potentially toxic elements at the site of the Romplumb metallurgical company and near the well-known Pb-Zn-Cu epithermal deposit of Baia Sprie located in the Neogene volcanic chain of the Eastern Carpathians, Romania. The average metal concentrations arranged in order of decreasing abundance are as follows (mg·kg−1): Mn (4098) > Zn (2093) > Pb (918) > Cu (489) > As (160) > Cr (37.51) > Ni (30.25) > Co (28.13) > Cd (9.72) > Hg (1.81). Several pollution indices were successfully used to assess the degree of contamination and ecological risk. The majority of sampling sites indicate high degrees of pollution, with two major hotspots identified. There are further sources, such as the Șuior (Pb-Zn-Au) and Săsar (Au-Ag) epithermal deposits, Cuprom company, and Bozânta tailing ponds, identified as contaminants. The Baia Mare mining district is causing a serious threat to the aquatic systems in the region, and it can be taken as a reference area for the human impact derived from the mining of mineral deposits of Au-Ag-Cu-Pb-Zn. It is imperative to reduce ecological risks and thereby protect the population living within this abandoned mining area. [ABSTRACT FROM AUTHOR]

Understanding geochemical zoning, including major components, minor components, and trace elements, in ore deposits can significantly improve Au exploration. Therefore, in this study, we focus on the geochemical characteristics of ore and alteration zones in the largest low-sulfidation (LS) epithermal Au–Ag deposit in Thailand, namely Chatree deposit. The occurrence of metal and metalloids can be distinguished into three groups: (1) major components in ore minerals (e.g., As, Cu, Fe, Pb, Sb, and Zn), (2) trace elements in ore minerals (e.g., As, Cd, Hg, and Mn), and (3) trace elements in gangue minerals (e.g., Mn). This study suggests that the ore minerals of a shallow system of the epithermal LS deposit are enriched in As, Sb, and Hg compared to the deeper system. Hydrothermal alteration leads to enrichment of K2O and depletion of Na2O and CaO. Besides major oxides, some low-field strength elements (e.g., Rb, and Ba) show the same behavior as K2O, whereas Sr is similar to CaO. In addition, positive Eu anomalies are associated with hydrothermal alteration. For metals and metalloids, arsenic is an important pathfinder element because its content is associated with the electrum occurrence and significantly increases toward the ore zone. Mn, Pb, and Cd are prominent in the ore zone; whereas, Ti, Al, and Cr decrease toward the ore zone due to dilution from silicification. Furthermore, even though the concentrations of As, Cd, Cr, Pb, and Ni in the ore and alteration zones are lower than Thailand's Total Threshold Limit Concentration (TTLC) for waste, the mine should still implement critical monitoring of these elements. [ABSTRACT FROM AUTHOR]

The formation and evolution of the foreland basin in the south of the Dabie Orogen are both closely related to the uplift of the orogenic belt. However, the Late Triassic paleoenvironment and the provenance of the sediments in the foreland basin remain controversial. Nine samples from the Upper Triassic Puqi Group of the foreland basin were analysed for whole‐rock major and trace elements and three sandstone samples were selected for zircon dating by U–Pb laser ablation inductively coupled plasma mass spectrometry. The concentrations of some major (e.g., CaO and Na2O) and trace (e.g., Rb, Sr and Ba) elements varied over a large range and showed different degrees of depletion. A series of major and trace element indicators, as well as the patterns of the rare earth elements, suggested derivation from felsic igneous rocks. The Late Triassic experienced fluctuations between cold warm climates, as indicated by the chemical weathering index ranging from 51.33 to 88.65. The CaO/(FeO + CaO), Rb/Sr and Ba/K ratios indicated that the paleosalinity changed from high to low. The Fe2O3/FeO, U/Th, V/Cr and Ni/Co ratios indicated an oxidizing sedimentary environment. The cathodoluminescence images, Th/U ratios and rare earth elements patterns of the detrital zircons all indicated a magmatic origin. Three samples showed significant peak ages of 224, 440, 748, 1870 and 2492 Ma, corresponding to the development of the Dabie Orogen. Our comprehensive analyses suggest that the Upper Triassic Puqi Group was formed by deposition during continental–continental collision. The Dabie Orogen was exhumed in the Late Triassic and supplied detrital sediments to the foreland basin. [ABSTRACT FROM AUTHOR]

In this study, a novel lithium metaborate fusion technique using a homemade fusion furnace and graphite crucibles was developed to produce homogeneous glasses from silicate rock powder. The glasses were then analyzed for both major and trace element concentrations by LA-ICP-MS. The parameters of the ratio of flux-to-sample, melting temperature and time, and closed fusion were optimized. It was found that homogeneous glasses could be obtained, and the loss of Pb was effectively suppressed at a low melting temperature and short time (900 or 950 °C for 5 min) in closed fusion. Compared to Pt or Pt–Au crucibles in the traditional flux fusion method, homemade graphite crucibles are more economical and omit the need of any releasing agent because the bottom curve design allows the melt to shrink into a bead for easy removal. Accurate results by LA-ICP-MS can be directly obtained by applying a quantitative calibration strategy using 100% oxide normalization, which offers a solution for unknown sample analysis without the prior determination of the concentration of an internal standard element. The analytical results of 42 major and trace elements in 5 USGS silicate rock reference materials (covering mafic to felsic rock types) using the developed LiBO2 fusion technique are consistent with the reference values within 10% for most elements, and analytical precision (RSD) is within 10% for most elements. The developed method is simple for preparing homogeneous glasses from rock powders, which displays great potential for the rapid and accurate determination of mass fractions of major and trace elements in silicate rocks using LA-ICP-MS. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel MTCPPOMe/P-Mn x Cd 1-x S photocatalyst was designed and synthesized. • Pure water was decomposed to produce hydrogen without using sacrificial reagents. • Charge density difference calculation showed photoelectrons transfer direction. Photocatalytic water splitting over semiconductors is an important approach to solve the energy demand of human beings. Most photocatalytic H 2 generation reactions are conducted in the presence of sacrificial agent. However, the use of sacrificial reagents increases the cost of hydrogen generation. Realizing photocatalytic water splitting for hydrogen production without the addition of sacrificial agents is a major challenge for photocatalysts. The porphyrin MTCPPOMe and P doped Mn x Cd 1-x S make a significant contribution in facilitating the Mn x Cd 1-x S photocatalytic pure water splitting to H 2 reaction. Herein, a novel MTCPPOMe/P-Mn x Cd 1-x S (M = 2H, Fe, Co, Ni) composite catalyst which can efficiently split pure water without using sacrificial agents is developed. As a result, the H 2 generation rate of CoTCPPOMe/P-Mn 0.5 Cd 0.5 S is as high as 2.10 μmol h−1, which is 9.1 and 4.2 times higher than that of Mn 0.5 Cd 0.5 S (MCS) and P-Mn 0.5 Cd 0.5 S (P-MCS), respectively. P doped Mn x Cd 1-x S inhibits the recombination of photogenerated carriers, and introduction of MTCPPOMe as co-catalyst enhances the reduction capacity. In summary, an efficient and economical photocatalystis prepared for pure water splitting to prepare hydrogen. [ABSTRACT FROM AUTHOR]

Active moss biomonitoring, the so-called moss bag technique, widely applied in many countries, for the first time, was applied to assess the air quality in Ulaanbaatar (Mongolia). Moss bags with Sphagnum girgensohnii Russow were exposed in triplicate in three different periods: December–February, March–May, and December–May at 13 governmental air quality monitoring stations located in the vicinity of thermal power plants and residential areas. The plant tissue content of Al, Ba, Co, Cd, Cr, Cu, Fe, Mn, P, Pb, Sr, S, V, As, and Zn was determined using inductively coupled plasma-optical emission spectrometry, and a direct mercury analyzer was used to determine the Hg content. The samples in residential areas and near thermal power plants that were exposed for 3 months in winter and for 6 months (winter to spring) were characterized by the highest accumulation of the elements. In the moss bags exposed during spring, maximum accumulation of the determined elements was noted in residential areas and near main roads. Regardless of the exposure time and duration, the highest accumulation of Al, Fe, and V was determined at Dambadarjaa air quality station located near a highway and of Hg near the Amgalan power plant. Significant differences in element accumulation between seasons were observed, thus, the accumulation of Al, Ba, As, Co, Cr, Fe, Pb, V, and Zn was higher in spring, while P and S had higher content in the moss samples exposed during winter. The accumulation of elements over the 6-month exposure period was 1.1–6.7 times higher than that of the 3-month periods. Thus, the 6-month exposure can be considered a reliable deployment period as it ensures an adequate signal in terms of enrichment of pollutants. Factor analysis was applied to highlight the association of elements and to link them with possible sources of emission. Three factors were determined, the first one included Al, As, Ba, Co, Cr, Fe, Mn, Pb, Sr, and V and was identified as a geogenic–anthropogenic, the second (Cu, P, and S) and third (Cd and Zn) factors suggested anthropogenic origin. The Relative accumulation factor and enrichment factor were calculated to evaluate the level of air pollution and possible element sources. Considerable contributors to air pollution were Zn, Fe, As, V, Cr, and Al, which may originate from airborne soil particles of crustal matter or transport, as well as coal combustion for heating and cooking. [ABSTRACT FROM AUTHOR]

This research aims to assess the content of some ions and trace elements in water sources in 24 rural Roma communities in Transylvania in order to assess the human health risk associated with exposure to such elements and ions. To this end, eight ions (F−, Cl−, Br−, NO2−, NO3−, SO42−, PO43−, NH4+) and ten trace elements (Cr, Ni, As, Pb, Cd, Mn, Cu, Zn, Fe, and Hg) were determined in 71 water samples by ion chromatography coupled with a conductivity detector for ions and atomic absorption spectrophotometry for all trace elements. General parameters were also determined. Non-conformity (as number of samples), according to the EU Drinking Water Directive, was observed as follows: pH (7), EC (7), hardness (1), oxidizability (15), Cl− (4), NO3− (30), SO42− (6), Fe (16), Mn (14), As (3), and Ni (1 sample). The incidence of ions was Cl− (71), SO42− (70), F− (67), NO3− (65), NH4+ (21), Br− (10), PO43−, and NO2− (1 sample) and for trace elements, Mn (59), Fe (50), As (38), Ni (32), Cu (29), Zn (28), Cd (12), Cr (11), and Pb (3 samples). Hg was not detected. Non-carcinogenic (HI) values exceeded one for As in 13 Roma communities, with higher values for children than for adults. For NO3−, the HI values were >1 in 12 for adults and 14 communities for children. The carcinogenic risk (CR) for As through ingestion ranged from 0.795 to 3.50 × 10−4 for adults and from 1.215 to 5.30 × 10−4 for children. CR by dermal contact was in the range of ×10−6 both for adults and children. [ABSTRACT FROM AUTHOR]

The photocatalytic overall water splitting performance of the bandgap controllable ZnxCd1−xS solid solution is still restricted by its photo‐corrosion. In this study, amorphous tungsten phosphosulphide (W‐S‐P) modified ZnxCd1−xS solid solution is successfully prepared as a visible‐light‐driven photocatalyst and an efficient and stable ZnxCd1−xS/W‐S‐P heterojunction is constructed through intimate W‐S covalent bonds for efficient photocatalytic overall water splitting. The hydrogen evolution rate of the composite catalyst reached 18899.6 μmol g−1 h−1, which is 86 times and 5 times higher than that of W‐S‐P and Zn0.5Cd0.5S, respectively. At this time, the precipitation rates of H2 and O2 were 157.07 μmol g−1 h−1 and 78.05 μmol g−1 h−1 without any noble metal catalyst. In this work, the overall water splitting efficiency of the catalyst is greatly improved by constructing a ZnxCd1−xS/W‐S‐P Schottky heterojunction, which further inhibits the photo‐corrosion of the ZnxCd1−xS catalyst. At the same time, the strong internal electric field greatly improves the charge transfer efficiency. It provides a new idea for an in‐depth understanding of the chemical changes of elemental binding energy in ZnxCd1−xS solid solution and the design of new binary photocatalytic materials. [ABSTRACT FROM AUTHOR]

Urban agricultural soils have important social, environmental, and economic roles in big cities, contributing to their sustainability. However, food production in urban soils may be compromised due to soil pollution that resulted from decades of industrial, non-regulated environmental activity and mobile transport. In this study, 12 soils from the urban agricultural area of Rome (Italy) were analyzed for the potentially toxic elements (PTEs) Be, Ba, Pb, Co, Ni, V, Zn, Hg, Cd, As, Cu, and Cr. All but one of the soils under analysis were characterized by at least one PTE concentration above the threshold limit defined by the D.Lgs 152/06 for agricultural soils. Multivariate analysis showed that the soils could be classified into five clusters: clusters I and II had relatively lower mean PTE concentrations; clusters III, IV, and V had relatively higher mean PTE concentrations with several PTE concentrations above the threshold proposed by ILD. Three factors contributing to the variability of the PTE's concentration in the soils under investigation were identified: a geological factor related to PTE As, Ba, Be, and V; an anthropogenic factor related to Pb and Cu; and a mixed factor related to Co, Cr, Ni, and Zn. High PTE content may limit the utilization of urban soils for food production. [ABSTRACT FROM AUTHOR]

Traffic borne pollutants negatively affect organisms. This study aimed to determine the impact of traffic pollution on Auchenorrhyncha species and their usage as biomonitor for metal pollution. The study was carried out in the cherry orchard near the Amasya-Samsun D100/E80 motorway in Amasya, Türkiye. Metal concentrations in specimens tended to decrease with the increasing distance from the motorway. Significant variations were determined in some metal concentrations based on distance from the motorway. The maximum and minimum metal concentrations were obtained from 0 to 100 m, respectively. Negative relationships were determined between distance from the motorway and Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb concentrations in Arboridia versuta (Melichar, 1897), and Cd, Co, Cr, Cu, Ni and Pb concentrations in Psammotettix provincialis (Ribaut, 1925). Metals were accumulated in the body of specimens. Therefore, it is thought that Auchenorrhyncha species may be used as a biomonitor for metal pollution due to their high metal concentrations. [ABSTRACT FROM AUTHOR]

The present study aimed to examine elemental contamination near the residential areas of four coal thermal power plants in India. Water and surface soil samples were collected from various geographic sites around Chennai, Korba, Rupnagar, and Udupi power plants. The study identified aluminum (Al), arsenic (As), chromium (Cr), cobalt (Co), copper (Cu), cadmium (Cd), iron (Fe), lithium (Li), magnesium (Mg), manganese (Mn), mercury (Hg), nickel (Ni), zinc (Zn), and lead (Pb) in water and soil samples. Further, soil morphology was also studied using the SEM and EDX. Additionally, using non-cancerous and cancerous risk indices, human health hazards through consuming contaminated water and soil were estimated. Results indicated that Fe and Mn concentrations in water exceeded the standard limits, i.e., the Fe (0.36 mg/l) at site 2 (Chennai), 0.490 mg/l at site 1, and 1.907 mg/l at site 3 (Udupi), while Mn was found as 0.28 mg/l at site 4 (Chennai), 0.27 mg/l at site 3 (Udupi), and 1.52 mg/l at site 4 (Rupnagar). In the case of soil, the maximum metal concentration (mg/kg) was found in Rupnagar, followed by Chennai, Korba, and Udupi. The hazard index (HI) for non-cancerous and cancerous risks was found within the USEPA standard limits, indicating insignificant health risks to the adjoining population of coal thermal power plants. This study provides baseline information regarding the elemental composition in water and soil and the associated health risk status around Indian coal thermal power plants. [ABSTRACT FROM AUTHOR]

Utah Lake is one of the largest freshwater bodies in the West and a valuable resource for agricultural and recreational activities in the region. However, it has suffered elevated trace metal and nutrient levels since the pioneer settlement in 1847. The objectives of this project were as follows: (1) investigate the temporal and spatial variations of trace metal and nutrient concentrations in Utah Lake and its tributaries; (2) model trace metal and nutrient concentrations across the lake using GIS spatial analysis techniques. We collected floc layer sediment samples quarterly as well as monthly water samples for trace metal and nutrient analyses at designated sites. GIS spatial analysis techniques were used to model the trace metal and nutrient concentrations in the lake. Elevated trace metal concentrations in river and lake water samples have been detected, especially in the month of June. The GIS modeling revealed that the highest trace metal and nutrient concentrations were located at the deepest part of the lake and near the Spanish Fork River inlet, respectively. Moreover, the results indicate that Utah Lake is not well mixed horizontally but well mixed vertically. Our findings can help state agencies address issues in water quality and management related to human–environment interactions. [ABSTRACT FROM AUTHOR]

Trace element diffusion is a powerful tracer of kinetic magmatic processes such as recharge and fluid exsolution. However, the dependence of diffusivities (D) on melt water contents is poorly quantified, and most trace element diffusivities were determined in water-free melts unrealistic for most natural magmatic systems. Here, we investigate the diffusion of the alkali trace elements Li, Rb, and Cs as a function of water content in rhyodacite, high-silica rhyolite, and peralkaline rhyolite. For the diffusion experiments, homogenous hydrous glass cylinders were produced from trace element-doped and undoped powdered glass with 1–8 wt% H 2 O. Glass cylinders with the same water content but different trace element concentrations were paired along polished contact surfaces. Diffusion experiments were conducted between 720 and 1100 °C at 100–700 MPa for 5–25 min using gas pressure vessels or a piston cylinder apparatus. Resulting diffusion profiles were analyzed by LA-ICPMS and evaluated by a Monte Carlo iterative fitting procedure for full error propagation. At a given experimental temperature, measured log 10 D values increase linearly with melt water content, with one order of magnitude increase for Li, two orders for Rb, and three orders for Cs from least hydrous (1 wt%) to wettest (8 wt%) experiment, due to a linear decrease in activation energies. Variations in major element composition only have a minor effect. We illustrate the impact of differential diffusion in hydrous silicic magmas on their trace element budget by coupling our data to a two-phase mechanical model of channelized fluid transport in magmatic systems. Quantifying water-dependent diffusivities provides an important tool to track the exsolution, mass and rate of fluid transport within long-lived shallow mushy magma reservoirs in the Earth's crust. [ABSTRACT FROM AUTHOR]

A high photoluminescence (PL)-based nanosensor based on graphene quantum dots (GQDs) is fabricated for the detection of toxic ions Ag+, Ce2+, Cd2+, Cu2+, Cr2+, Pb2+, Sn2+, and Fe3+, p-nitrophenol, and thioacetamide in water. The quenching of PL spectra indicates that the complex of GQDs/Fe(III) shows a high florescent quenching efficiency (~ 75%) toward the hydrophobic surface of the GQDs. The limit of detection for Fe(III) concentration 40 ± 2 nM, with high linearity and sensitivity. The change of the zeta potential value proves the attachment of Fe (III) ions to the surface of the GQDs. The GQDs/Fe(III) complexes can be utilized as a turn-OFF or turn-ON type fluorescence probe for p-nitrophenol (turn-OFF) detection with 5 ± 1 pM concentration and the sulfur (turn-ON) detection with 7.6 ± 1 pM. The proposed method is facile, sensitive and fast, which makes it ideal for nanosensors to detect water quality of rivers, ponds, or industrial wastes. [ABSTRACT FROM AUTHOR]

This comprehensive study aimed to evaluate the water quality and sediment contamination in the Chuhe River in Nanjing. The spatial assessment of 10 samples collected in September highlighted that, in surface water, Copper (Cu) > Nickel (Ni) > Zinc (Zn) > Chromium (Cr) > Lead (Pb) > Arsenic (As) > Cadmium (Cd) > Mercury (Hg), whereas in sediments, Zn > Cr > Cu > Pb > Ni > As > Cd > Hg. The coefficient of variation (CV) for Ni and Zn in surface water was >15, whereas As, Cu, Pb, and Ni had a CV that was higher than 15 in sediments, indicating variability in contamination sources. The Pollution Load Index values ranged between 2.16 and 3.05, reflecting varying contamination levels across samples. The Geoaccumulation Index data also showed moderate-to-considerable contamination, especially for elements such as Cd and Cu. Correlation analyses in water and sediments unearthed significant relationships, with notable links between Cu and Pb in the water and strong correlations between As and Cu and between Cr and Ni in sediments. In sediments, Total Nitrogen and Phosphorus were significantly correlated with As, Cu, Pb, and Ni. The Potential Ecological Response Index for sediments indicated that they are at medium to high risk (307.47 ± 33.17) and could be potentially detrimental to aquatic life in the tributary. The tributary, influenced by agricultural runoff, residential areas, and other anthropogenic activities, showed that despite Nemerow pollution index values for water samples being below 1, sediment analysis indicated areas of concern. Principal Component Analysis (PCA) was conducted to identify the potential sources of heavy metal contamination. In surface water, shared negative loadings on PC 1 (60.11%) indicated a unified influence, likely from agricultural runoff, while PC 2 (14.26%) revealed additional complexities. Sediments exhibited a unique signature on PC 1 (67.05%), associated with cumulative agricultural impacts, with PC 2 (18.08%) providing insights into nuanced factors, such as sediment composition and dynamic interactions. These findings offer a complete insight into the Chuhe River tributary's condition, underlining the urgency for ongoing monitoring and potential remediation measures. [ABSTRACT FROM AUTHOR]

In contrast to fairly good knowledge of dissolved carbon and major elements in great Arctic rivers, seasonally resolved concentrations of many trace elements remain poorly characterized, hindering assessment of the current status and possible future changes in the hydrochemistry of the Eurasian Arctic. To fill this gap, here we present results for a broad suite of trace elements in the largest rivers of the Russian Arctic (Ob, Yenisey, Lena, and Kolyma). For context, we also present results for major elements that are more routinely measured in these rivers. Water samples for this study were collected during an international campaign called PARTNERS from 2004 through 2006. A comparison of element concentrations obtained for Arctic rivers in this study with average concentrations in the world's rivers shows that most elements in the Arctic rivers are similar to or significantly lower than the world average. The mineral content of the three greatest rivers (Ob, Yenisey, and Lena) varies within a narrow range (from 107 mg/L for Yenisey to 123 mg/L for Ob). The Kolyma's mineral content is significantly lower (52.4 mg/L). Fluxes of all major and trace elements were calculated using average concentrations and average water discharge for the 2004–2006 period. Based on these flux estimates, specific export (i.e., t/km2/y) for most of the elements was greatest for the Lena, followed by the Yenisey, Ob, and Kolyma in decreasing order. Element pairwise correlation analysis identified several distinct groups of elements depending on their sources and relative mobility in the river water. There was a negative correlation between Fe and DOC concentration in the Ob River, which could be linked to different sources of these components in this river. The annual yields of major and trace elements calculated for each river were generally consistent with values assessed for other mid-size and small rivers of the Eurasian subarctic. [ABSTRACT FROM AUTHOR]