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With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation. [ABSTRACT FROM AUTHOR]

Ferroptosis is a novel form of programmed cell death caused by damage to lipid membranes due to the accumulation of lipid peroxides in response to various stimuli, such as high levels of iron, oxidative stress, metabolic disturbance, etc. Sugar, lipid, amino acid, and iron metabolism are crucial in regulating ferroptosis. The solute carrier transporters (SLCs) family, known as the "metabolic gating" of cells, is responsible for transporting intracellular nutrients and metabolites. Recent studies have highlighted the significant role of SLCs family members in ferroptosis by controlling the transport of various nutrients. Here, we summarized the function and mechanism of SLCs in ferroptosis regulated by ion, metabolic control of nutrients, and multiple signaling pathways, with a focus on SLC–related transporters that primarily transport five significant components: glucose, amino acid, lipid, trace metal ion, and other ion. Furthermore, the potential clinical applications of targeting SLCs with ferroptosis inducers for various diseases, including tumors, are discussed. Overall, this paper delves into the novel roles of the SLCs family in ferroptosis, aiming to enhance our understanding of the regulatory mechanisms of ferroptosis and identify new therapeutic targets for clinical applications. [ABSTRACT FROM AUTHOR]

Trace elements released into the atmosphere by human activities, such as fossil fuel combustion, flow into forest ecosystems via wet and dry deposition and can flow out via mountainous stream water. The Kajikawa catchment site in Niigata Prefecture, located on the Sea of Japan side in central Japan, suffers from large amounts of acidic substance deposition due to its geographical conditions and meteorological seasonality and is affected by transboundary air pollution originating from the Asian continent due to northwesterly seasonal winds in winter. This study determined the concentrations of trace elements dissolved in precipitation and stream water to comprehensively evaluate the effects of transboundary air pollution on forest ecosystems. The results showed that the concentrations of trace elements and major inorganic ions in precipitation tended to be high in winter and low in summer. The fluxes of many trace elements also increased in winter, reflecting high precipitation amount. Except for Sr, the enrichment factors of the highly enriched trace elements did not show clear seasonality. Therefore, they were continuously influenced by anthropogenic activities. Furthermore, the stable Pb isotope ratio changed significantly during the observation period; however, this was not explained by seasonal changes. This study revealed that trace elements are transported to the Sea of Japan side in central Japan, especially in winter; however, their quantity and content change in response to changes in local and transboundary air pollution. [ABSTRACT FROM AUTHOR]

Sebkhat Soliman included in the Ramsar Convention is a wetland of international importance. This area is of great ecological interest considering the quality and the richness of the flora and the diversity of the avifauna. This site receives a large amount of water through the EL Bey River. In order to assess the levels of contamination, concentrations of six heavy metals, including Cr, Cu, Pb, Ni, Mn, and Zn, were examined in 25 surface sediment samples from El Bey Wadi. These concentrations, which were expressed in mg/kg of dry weight, showed that Pb ranged from 5.52 to 41.66, Zn from 26.94 to 1471.89, Cu from 91.97 to 260.05, Ni from 9.35 to 140.45, Cr from 25. It's important to note that the highest metal concentrations have been found in site 5 which is frequently exposed to local industrial pollutant sources and in sites that are frequently inundated by river water that is carrying away industrial waste from the cities of Grombalia and Bou-Argoub. The mean EF values for Cu, Mn and Ni were between 3 and 5 in the sediments of the El Bey River, suggesting moderate enrichment, while the mean EF values for Pb, Zn and Cr indicating respectively moderate to severe enrichment and very severe enrichment. CF values for Cr, Cu and Zn were > 6 in sediments taken from the fifth site, which denotes a very high contamination by these metals. At site 5, PLI value (4.09), reflecting that its sediment is heavily polluted. Hierarchical cluster analysis-based complementary statistical methods have demonstrated that Mn is lithogenic and other analyzed metals are anthropogenic. [ABSTRACT FROM AUTHOR]

In this work, the seven-step extraction procedure (SSEP) proposed by our laboratory team was modified to reduce the number of fractions from seven to five (FSEP) without affecting its effectiveness. By this way, the modified SSEP was investigated by comparing the quantity of trace (Cd, Co, Cr, Cu, Ni, Zn) and major (Ca, Fe, Mn) elements leached from two sediments (TH2 and T16). Compared to the SSEP, the shortened sequential test allows to reach the same results in terms of reproductibility. Results confirm that the water-soluble step is negligeable and can be omitted for the sediments. The percentage of the total leached elements Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn were 23%, 13%, 58%, 55%, 92%, 63%, 81%, 65% and 80%, respectively, for both procedures SSEP and FSEP. However, merging the reducible fractions revealed for some elements a little reduction of the leached quantities in comparison to the original SSEP. Over reducible fraction, the leached Fe element in T16, achieves 4% for SSEP and 3% for FSEP. This was explained by the partial dissolution of the amorphous and crystalline irons. Based on the reduced number of fractions, the used extraction filters (28 Vs 20) and the extraction time (18 h Vs 13.5 h), FSEP appeared to be easier for manipulation without loss of its effectiveness. However, the choice of the FSEP must be deduced from the physicochemical properties of the sample and the aim of the envisaged study. [ABSTRACT FROM AUTHOR]

To gain insights into the spatial distribution, ecological risk and origins of heavy metals in surface sediments of lacustrine ecosystems in Cameroon, the content of 7 trace metals (Fe, Cr, Zn, Cu, Ni, Pb and Cd) in sediments from 60 sampling stations in 5 lacustrine environments of different formation contexts. The selected metals were investigated based on inductively coupled plasma mass spectrometry. The results revealed that the average concentrations of Cr, Cu and Cd were higher than the geochemical Threshold values. On the basis of the spatial variation, the studied metals vary quantitatively in the following order: Fe > Cr > Zn > Cu > Ni > Pb > Cd. The calculated enrichment factor (EF) and geo-accumulation index (Igeo) showed that, sediments from large cities and industrial sites had moderate enrichment (3 < EF ≤ 5) and were moderately to severely contaminated (2 < Igeo < 3) while those from low population and rural areas had minor enrichment (1 < EF ≤ 3) and were moderately contaminated (1 < Igeo < 2). With regards to cumulative pollution, the pollution load index (PLI) and the sediment pollution index (SPI) coupled with the potential ecological risk factor (Er) and the potential ecological risk index (RI), the sediments of the lakes are polluted (SPI and PLI > 1) to some extent but with a low ecological risk (Er < 40 and RI < 150). The results of Pearson correlation, principal component analysis (PCA), and cluster analysis (CA) identified three main sources: Ni would have a natural source; Pb from anthropogenic sources, and the other metals (Fe, Cr, Zn, Cu, and Cd) could have a mixed source (anthropogenic and natural). These findings serve as a scientific foundation for the advancement and use of these lake environments, which are the most attractive sites. [ABSTRACT FROM AUTHOR]

This study was conducted in a greenhouse pot experiment to assess the effects of biochar (BC) or activated carbon (AC) alone or in combination with arbuscular mycorrhizal fungus (AMF) Glomus mosseae or acid-producing bacteria (BA) Bacillus polymyxa on plant growth, EDTA-extractable Cd and Pb, and contents of heavy metals (Cd and Pb) and nutrients (Ca, Mg, K, and P) in maize (Zea mays L.) grown on sewage wastewater contaminated soil. The results showed that most treatments with BC, AC, or its co-application with microbial inoculation led significantly to greater nutrient uptake and promoted growth of maize than non-treated plants. Additionally, the soil additives used decreased the amounts of EDTA-extractable Cd (by 28.7%-100%) and Pb (by 22.8%-94.3%). The applied treatments caused significant decreases in Cd concentrations and the bioconcentration factor (BCF) of Zea mays. The highest shoot Cd reduction was observed for AC (53%), followed by AC+BA (36.9%) > AMF (34.5%) > AC+AMF (28.5) > BA (28.3%) > BC+BA (26.1%) > BC (22.7%). However, more Cd was accumulated in the roots of plants treated with AMF by 63.7% with a lower value of translocation factor (TF) compared to control soil. In contrast, the treatments increased the levels of Pb in the maize plants, and BC coupled with AMF showed the greatest Pb accumulation. It could be concluded that the investigated additives can be applied as immobilizing agents for Cd in the soil but maize plants as phytoextractants for both metals in sewage-contaminated soil are not feasible, as indicated by insufficient phytoextraction efficiency. [ABSTRACT FROM AUTHOR]

Pollution in the Noyyal river is a well-known and documented issue and recently, heavy metal contamination has become a serious issue requiring immediate attention. So, to understand the severity of heavy metal contamination in the surface water and sediments of the Noyyal river, a comprehensive study was conducted. About 27 surface water samples and 25 sediment samples were collected at different sites along the Noyyal river. The concentrations of heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS). The Noyyal river's surface water showed significant variations with nickel (Ni), copper (Cu), and zinc (Zn) concentrations exceeding acceptable limits for irrigation and aquatic life. Lead (Pb) concentrations were within acceptable limits for irrigation but potentially harmful to aquatic organisms. Noyyal river sediments also contained varying concentrations of chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), and gallium (Ga). Various assessment indices were employed to assess the eco-biological and human health risks associated with heavy metal contamination. The results highlighted alarming ecological and biological risks due to the accumulation of trace metals. Sediments exhibited high ecological risk (ERI values ranging from 43.81 to 371.43), while surface water samples intended for irrigation and aquatic purposes displayed extreme risks (ERI values exceeding 1200) to agricultural crops and aquatic organisms. The probability of toxicity to aquatic organisms, particularly benthic communities, was over 76% according to the biological risk assessment. The study also identified potential non-carcinogenic risks associated with metals like chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) in the sediments. Moreover, elevated levels of Cr, Ni, and Cu in both sediments and surface water were likely to pose significant carcinogenic risks to exposed adults. Additionally, the heavy metal toxicity load in both surface water and sediments exceeded permissible limits, highlighting the urgent need for efficient removal strategies. [ABSTRACT FROM AUTHOR]

The anomalous increases or deficits in the human body can be detected by the development of accurate and sensitive methods for metal quantification in low-level concentrations. Two digestion procedures have been tested on whole blood samples for use in inductively coupled plasma optical emission spectrometry trace metal analysis (ICP-OES). The two procedures are, (microwave digestion with nitric acid and hydrogen peroxide), and (simple dilution digestion with nitric acid, N-butanol, and Triton X-100). According to the findings, the overall recoveries of all determining metals for the microwave digestion were in the range of (96%) of the expected levels, whereas for simple dilution digestion they were in the range of (85–88%) of the expected levels. The results showed a significant difference in the recovery ratios in favor of lead (Pd) and cadmium (Cd) between simple dilution and microwave digestion procedures. The findings also show that the content of these metals may be reliably measured using simple dilution and microwave digestion procedures. Abbreviations: ICP-OES: Induction coupled optical emission spectroscopy; LOD: Limit of detection; LOQ: Limit quantification; AAPCC: American Association of Poison Control Centers; NAUSS: Naif Arab University for Security Sciences; %RSD: Relative standard deviation). [ABSTRACT FROM AUTHOR]

Concentrations of toxic metals (Hg, Pb, and Cd) were determined in the muscles of Lepomis macrochirus, Barbus callensis, and Barbus nasus caught from the Moulouya River of Morocco by graphite furnace (for Pb and Cd) and cold vapour (for Hg) atomic absorption spectrometry, after acid digestion. Although the concentration of metals in some species was relatively high, no health risk has been identified in comparison to the maximum limits as set by the European Commission. The order of increasing concentrations was Cd < Hg < Pb. Calculated Target Hazard Quotients and Hazard Indices were below 1, indicating that the intake of metals via consumption of the muscles of both fish species does not represent a hazard to human health. [ABSTRACT FROM AUTHOR]

Multi-channel dilution analysis (MCDA) is a new calibration method that performs multiple dilutions of a standard solution as it makes its way from an autosampler to an analytical instrument. MCDA is based on the standard dilution analysis (SDA) method that combines the traditional standard additions and internal standardization calibration methods, correcting for both matrix interferences and fluctuations in signal levels associated with variations in the sample environment. Analysts operate the instrument in the normal manner, as all dilutions are performed automatically by splitting the sample stream entering the instrument into multiple channels of different tubing diameters and lengths. This setup results in a signal "stairstep" as portions of solution are measured at different points in time. A calibration curve is prepared from the plateau regions of the signal stairstep. MCDA has been exhibited using inductively coupled plasma optical emission spectrometry, which is a workhorse for the determination of trace metals in solution. However, MCDA is applicable for any analyte of interest in any sample type, as long as the selected measurement technique accepts samples as a flowing liquid stream. MCDA is applied to the analysis of three certified reference materials by inductively coupled plasma optical emission spectrometry (ICP-OES). Percent recoveries for a suite of analytes range from 87--106%, with relative standard deviations on the order of 1%. MCDA simplifies the analysis process, increasing sample throughput by significantly decreasing the time required for solution preparation. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is a silent killer and has become a pervasive issue in various regions worldwide, particularly within developing nations such as Nigeria. This study undertook a thorough examination of 120 scholarly articles published from 2000 to 2019, aimed at evaluating the prevalence of heavy metal pollution in soils, aquatic environments, and food sources including crops, meat, and dairy products. Methodologies employed for sample collection and metal quantification were critically assessed, alongside an extensive discussion on the concentrations, sources, and levels of contamination observed. The investigation revealed elevated concentrations of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), cobalt (Co), chromium (Cr), iron (Fe), and arsenic (As) across all examined locales, with average metal concentrations surpassing World Health Organization/Food and Agriculture Organization (WHO/FAO) guidelines for soil. Furthermore, higher metal concentrations were detected in surface and well waters, whereas borehole groundwaters were relatively pollution-free. Analysis of food crops, meat, and milk demonstrated metal concentrations exceeding WHO/FAO standards across all urban areas studied. Contrary to expectations of lithogenic toxicity, the primary sources of contamination were identified as anthropogenic, stemming from dumpsites, landfill sites, mining operations, runoff and seepage from automotive repair workshops, petroleum hydrocarbon spills, and effluents from industrial plants. The geo-accumulation index (Igeo) analysis revealed significant soil contamination with Fe and Cd, classified under extremely serious and moderate contamination levels, respectively. This comprehensive review highlights the necessity for viable and clear policy interventions to mitigate heavy metal pollution and advocates for the rigorous monitoring and control of industrial activities. [ABSTRACT FROM AUTHOR]

Bangladesh has one of the highest per capita rice consumption worldwide. However, heavy metals from the soil and contaminated irrigated water are translocated into rice grains and pose a health hazard to humans in Bangladesh. We investigated trace metal contamination in rice cultivated in three sites in Bangladesh, to screen heavily contaminated trace metals and to assess the health risk via rice consumption. Rice was cultivated using groundwater in rural areas of Bangladesh and contaminated river water near Dhaka City on 30 rice cultivars. The metals contained in rice grains were measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to investigate their contamination levels. Hazard quotient values were calculated based on the measured concentrations to assess human health risks associated with rice consumption. We showed that rice grown with groundwater and contaminated river water irrigation in Bangladesh was contaminated with different trace metals, particularly, Pb and As. The mean and maximum hazard quotient values of Pb and As were 1.4 and 3.2, and 0.42 and 1.2, respectively, implying that these rice consumption may adversely affect the health of the people living in the contaminated areas. Moreover, Cd, Mn, Ni, and Zn were detected at relatively high concentrations in rice grains irrigated with river water contaminated with industrial wastewater around Dhaka City. No dependence on water sources, such as groundwater and river water, was found for As and Pb concentrations in rice. In addition to the previously investigated As pollution, this study demonstrated that Pb contamination of Bangladeshi rice was a serious problem for the health of Bangladeshis. [ABSTRACT FROM AUTHOR]

The present study aimed to assess trace metal speciation trends in the water and sediments of Mazowe Dam, a typical sub-tropical dam ecosystem impacted by gold mining and agriculture in Zimbabwe. The elements studied include Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn. Elemental speciation in the water column was determined using Visual MINTEQ version 3.1 geochemical computer modelling, while speciation in the sediment phase was determined using sequential extraction techniques. For each element, the data obtained were subjected to extensive correlation analysis to identify intra- and inter-metal species interactions in the water column and the sediment phase, as well as across the water–sediment interface. Possible mechanisms to account for the observed species interactions are proposed. In the water column, Co was predicted to have the highest number of chemical species (9), Cd and Zn (8), Mn and Fe (7), Ni (6), Pb (5), Al and Cu (3), Cr, Hg, and As have the least (2). In the sediment, Al, As, Co, Cr, Cu, Fe, Ni and Fe mainly exist in the residual fraction, while Zn and Mn concentrations in fractions vary per sampling site, with no fraction that is dominant across the sampling sites. Equilibrium exchange reactions across the water–sediment interface were observed e.g., for Cd species /FA2Cd (aq) and Co species /FACo+2G (aq), and /FA2Co (aq). This study is valuable in highlighting trace metal speciation in a tropical dam ecosystem in Africa and adds to the growing knowledge about the behaviour of trace metals in aquatic ecosystems in the region and globally. [ABSTRACT FROM AUTHOR]

Irrigation management controls biogeochemical cycles in rice production. Under flooded paddy conditions, arsenic becomes plant-available as iron-reducing conditions ensue, while oxic conditions lead to increased plant availability of Cd in acidic soils. Because Cd enters rice through Mn transporters, we hypothesized that irrigation resulting in intermediate redox could simultaneously limit both As and Cd in rice grain due to As retention in soil and Mn competition for Cd uptake. In a 2 year field study, we used 6 irrigation managements that varied in extent and frequency of inundation, and we observed strong effects of irrigation management on porewater chemistry, soil redox potentials, plant As and Cd concentrations, plant nutrient concentrations, and methane emissions. Plant As decreased with drier irrigation management, but in the grain this effect was stronger for organic As than for inorganic As. Grain organic As, but not inorganic As, was strongly and positively correlated with cumulative methane emissions. Conversely, plant Cd increased under more aerobic irrigation management and grain Cd was negatively correlated with porewater Mn. A hazard index approach showed that in the tested soil with low levels of As and Cd (5.4 and 0.072 mg/kg, respectively), irrigation management could not simultaneously decrease grain As and Cd. Many soil properties, such as reducible As, available Cd, soil pH, available S, and soil organic matter should be considered when attempting to optimize irrigation management when the goal is decreasing the risk of As and Cd in rice grain. [ABSTRACT FROM AUTHOR]

The present article assesses, for the first time, the level of heavy metal pollution, determines possible sources and evaluates the health risks associated with groundwater in the Angads plain in Morocco, by employing a combination of tools including indices, statistical multivariate techniques and models for health risk assessment. The findings revealed that the concentrations of several heavy metals (95.83% for As and 41.66% for Pb) were above the WHO limit values. The heavy metal pollution index (HPI) and the heavy metal evaluation index (HEI) revealed that all samples were fit for consumption. Health risks revealed that the hazard index (HI) values for dermal exposure were below the limit, while for oral exposure, 95.83% of samples were above the limit. In addition, the carcinogenic risk (CR) results revealed that there is a possibility of cancer development due to lifetime exposure to this groundwater. [ABSTRACT FROM AUTHOR]

In this study, the concentrations of cadmium (Cd), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in plants sampled from Mt. Madra were investigated. Furthermore, the distribution characteristics and source identification of potentially toxic metals were investigated with the application of Positive Matrix Factorization (PMF) modelling. Samples of 26 different plant species were taken from Mt. Madra at elevations ranging from 177 to 1347 m using the multi-point sampling approach. The metal quantities measured by ICP-OES are the following sequences (mean ± SD) (mg/kg): Fe (974.96 ± 29.6) > Mn (111.81 ± 2.6) > Zn (27.28 ± 0.2) > Ni (2.17 ± 0.03) > Pb (0.77 ± 0.01) > Cd (0.12 ± 0.01). According to the plant samples in which the highest values were determined, the metals are as follows: Cd (Lathyrus laxiflorus, 0.401 mg/kg), Fe (Ajuga orientalis, 7621.207 mg/kg), Mn (Castanea sativa, 724.927 mg/kg), Ni (Prunella laciniata, 6.947 mg/kg), Pb (Crataegus stevenii, 3.955 mg/kg) and Zn (Prunella laciniata, 50.802 mg/kg). The results of the PMF model showed that Cd had an atmospheric transport factor originated and transported from industrial activites, Ni had a substrate factor, Fe, Mn, Pb and Zn were influenced by different anthropogenic factors. [ABSTRACT FROM AUTHOR]

Sea urchin species are ecologically important in the Gulf of California and are becoming popular as a local fishery due to their commercial value. The most abundant species are Echinometra vanbrunti, Eucidaris thouarsii, and Tripneustes depressus. The objective of this study was to evaluate cadmium, lead, copper, zinc, and iron concentrations, as well as stable isotope values in these sea urchin species in the Santa Rosalia mining area (STR), in three sites: Punta Gorda, Punta el Aterrizaje, and Punta Salina. The highest Fe concentration (100.2 mg kg−1) was found in E. vanbrunti, while the highest concentrations of Pb (15.1 mg kg−1), Cu (14.5 mg kg−1), and Zn (347.7 mg kg−1) were recorded in E. thouarsii, and the highest Cd concentration (10.8 mg kg−1) was found in T. depressus. The main health risk of trace metal pollution in STR may be caused by Cd and Pb. δ15N and δ13C values were higher in E. thouarsii and T. depressus, respectively; E. thouarsii has the highest trophic position. Specimen size was not related to metal concentrations, but a positive relationship was observed between specimen size and isotopic values in T. depressus. The three species showed different bioaccumulation patterns for the metals analyzed. Additionally, collection sites and seasons play an important role in the variability of metal concentration. [ABSTRACT FROM AUTHOR]

Nickel stable isotopes (δ60Ni) provide insight to Ni biogeochemistry in the modern and past oceans. Here, we present the first Pacific Ocean high‐resolution dissolved Ni concentration and δ60Ni data, from the US GEOTRACES GP15 cruise. As in other ocean basins, increases in δ60Ni toward the surface ocean are observed across the entire transect, reflecting preferential biological uptake of light Ni isotopes, however the observed magnitude of fractionation is larger in the tropical Pacific than the North Pacific Subtropical Gyre. Such surface ocean fractionation by phytoplankton should accumulate isotopically lighter Ni in the deep Pacific, yet we find that North Pacific deep ocean δ60Ni is similar to previously reported values from the deep Atlantic. Finally, we find that seawater dissolved δ60Ni in regions with hydrothermal input can be either higher or lower than background deep ocean δ60Ni, depending on vent geochemistry and proximity. Plain Language Summary: A habitable Earth relies on the growth of microscopic plants, called phytoplankton, in the ocean. Phytoplankton help regulate Earth's climate and their growth requires various nutrients in seawater, including a suite of metal elements such as iron, zinc, and nickel (Ni). These metals are called trace metals in the ocean because their concentrations are extremely low in seawater, yet they are essential micronutrients. Therefore, it is important to understand how much and how these elements are supplied to and removed out of the ocean, and how they are used by phytoplankton. To study this question, we analyzed Ni isotope ratios of hundreds of seawater samples collected from the Pacific Ocean—which is the ratio of naturally occurring Ni atoms with different numbers of neutrons and therefore slightly different masses. We find that surface seawater is more enriched in heavier Ni isotopes than the deep seawater, in particular around the tropical Pacific. The deep ocean has similar Ni isotope ratios across different ocean basins, from the Atlantic to the Pacific. Seawater Ni isotope ratios are impacted by rivers near Alaska, submarine volcanos near Hawaiʻi, and a submarine volcanic chain called the East Pacific Rise. Key Points: Enrichment of heavier Ni isotopes is observed in the surface ocean across the GP15 transect, particularly in the equatorial PacificNorth Pacific deep ocean Ni isotope composition is nearly homogeneous and similar to previously reported values from other ocean basinsHydrothermal activity can both decrease and increase seawater Ni isotope composition, depending on vent geochemistry and proximity [ABSTRACT FROM AUTHOR]

Trace metals and metalloids are groups of chemical elements that naturally occur in low concentrations and cycle in the environment driven by natural processes and human activities. They have a persistent and bio-accumulative tendency in the environment, and certain trace metals and metalloids have become a public health concern. This study assesses the concentration of eleven trace metals and a metalloid in sediments and catfish muscle from five study sites in the Eastern Tanzanian River basin. Forty catfish tissues and fifteen sediment samples were collected and analyzed using ICP-MS. Concentrations of As, Cd, Co, Pb, and Zn did not exceed the United States Environmental Protection Agency (USEPA) guideline for pollution of sediments, while Al Cr, Al, Mn, and V with values ranging from (118.54 to 70154.55) indicating moderately polluted. The stations Java-Sadaani and Matandu showed the highest Cr, Ni, and Cu concentrations, but the potential ecological risk index (RI) was low (RI < 95). In the catfish muscle tissue, the levels of Cd, Pb, Cu, and Zn did not surpass the EU and FAO/WHO limits and results ranged from 2.22 to 35.22mg/kg. Low levels of accumulation of Cd, Pb, and As were found in this study compared to catfish muscles from other studies, whereas the concentrations of other trace metals and metalloids analyzed had comparable results. Biota/sediment accumulation factors (BSAF) were all < 1. The weekly metal intake (MWI) results ranged from 6.89E-04 to 2.43E+01 μg/know-1week-1, indicating a low risk as the value did not exceed the FAO/WHO established Permissible Tolerable Weekly Intake (PTWI). The non-carcinogenic health risk result THQ was 4.43E-02 and the carcinogenic health risks result HI was 4.42E-05 which indicated tolerable levels of risks as both the values of the Target Hazard Quotient (THQ) and the Hazard Index (HI) was < 1, and the carcinogenic target risk (TR) is < 0.0001. The highest TR values were observed for Cr and Ni. We recommend a continued monitoring of the changes in trace metal levels in the environment and biota together with continuous public health education on the dangers of high levels of trace metals. [ABSTRACT FROM AUTHOR]

Deception Island (DI) is an active volcanic caldera in the South Shetland Islands, Antarctica, with an inner bay, Port Foster, formed by an ancient eruption. The bay's seafloor hydrofracture system contains hydrothermal seeps and submarine vents, which are a source of trace metals (TMs) like Fe, Ni, Co, V, and greenhouse gases (GHGs) such as CO2 and CH4. This study presents measurements of TMs and GHGs in Port Foster's surface waters during January-February 2021 to characterize their spatial distribution. TMs concentrations in the northeastern region of the bay, particularly V (74 nM), Fe (361 nM), Co (3.9 nM) and Ni (17.2 nM), were generally higher than in the Southern Ocean, likely due to hydrothermal activity. As some TMs such as Fe are scarce in the SO and limit primary productivity, inputs of these nutrients from DI into surrounding waters may also regionally promote increased primary productivity. Higher surface temperature (ST), elevated partial pressure of CO2 (pCO2), and lower salinity were found near submarine fumaroles, with ST positively correlated with pCO2 and negatively with salinity. Although hydrothermal sites showed localized CO2 outgassing, the bay overall acted as a CO2 sink, with a median flux of -2.78 mol m-2 yr-1 with an interquartile range (IQR) of 3.84 mol m-2 yr-1. CH4 highest concentration levels were found in the southeastern sector. The median concentration was 8.9 nM with an IQR of 1.9 nM, making Port Foster a regional net CH4 source with a median flux of 9.7 μmol m-2 d-1 and an IQR of 3.4 μmol m-2 d-1. Ultimately, the analysis of spatial patterns of the measured variables suggested that fumaroles of DI may be playing a significant role in the alteration of regional seawater biogeochemistry. [ABSTRACT FROM AUTHOR]

Background: At lower concentrations copper (Cu), zinc (Zn) and nickel (Ni) are trace metals essential for some bacterial enzymes. At higher concentrations they might alter and inhibit microbial functioning in a bioreactor treating wastewater. We investigated the effect of incremental concentrations of Cu, Zn and Ni on the bacterial community structure and their metabolic functions by shotgun metagenomics. Metal concentrations reported in previous studies to inhibit bacterial metabolism were investigated. Results: At 31.5 μM Cu, 112.4 μM Ni and 122.3 μM Zn, the most abundant bacteria were Achromobacter and Agrobacterium. When the metal concentration increased 2 or fivefold their abundance decreased and members of Delftia, Stenotrophomonas and Sphingomonas dominated. Although the heterotrophic metabolic functions based on the gene profile was not affected when the metal concentration increased, changes in the sulfur biogeochemical cycle were detected. Despite the large variations in the bacterial community structure when concentrations of Cu, Zn and Ni increased in the bioreactor, functional changes in carbon metabolism were small. Conclusions: Community richness and diversity replacement indexes decreased significantly with increased metal concentration. Delftia antagonized Pseudomonas and members of Xanthomonadaceae. The relative abundance of most bacterial genes remained unchanged despite a five-fold increase in the metal concentration, but that of some EPS genes required for exopolysaccharide synthesis, and those related to the reduction of nitrite to nitrous oxide decreased which may alter the bioreactor functioning. [ABSTRACT FROM AUTHOR]

Due to coastal development expansion, an increasing influx of pollutants enters the sea through riverine input and land runoff, threatening coastal ecosystems and posing a risk of eutrophication. In this study, trace metals (Fe, Mn, Cu, and Zn), and nutrients (constituents of N, P, and Si) were assessed in the summer surface seawater of Yantai Sishili Bay (YSB), Northern China focusing on the determination of concentration, spatial-temporal distribution and sources identification, while exploring their correlations. It also aimed to clarify the eutrophication status and evaluate the linear relationships between eutrophication, trace metals, and nutrients in YSB. Over three years (2021-2023), the total dissolved concentrations of Fe, Mn, Cu, and Zn ranged from 4.79-26.71, 0.19-6.41, 0.26-1.53, and 0.74-13.12 µg/L, respectively. Concurrently, nutrient concentrations including NO2-, NO3-, NH4+, PO43-, and DSi exhibited a range of 0.37-11.66, 2.04-178.30, 1.69-70.01, 0.02-16.68, and 0.02-0.71 µg/L respectively. These concentrations revealed a gradual decrease from nearshore to offshore and the temporal variation also showed significant patterns from year to year, indicating distinct regional variations. The primary contributors to the trace metals and nutrients in the study region were recognized as external contributions stemming from natural, anthropogenic, and atmospheric deposition through correlation and principal component analysis. More specifically, riverine input and coastal farming contributed large amounts of nutrients to coastal waters, threatening a potential risk of eutrophication. The eutrophication evaluation expressed below the mild eutrophication level and was far lower than the other global and Chinese bays. The linear correlation between eutrophication and trace metals revealed a weak positive correlation but a significant correlation with nutrients. Despite the absence of significant eutrophication in the bay, potential risks were identified due to identifiable sources of nutrient and trace metal inputs. The findings provided insights to guide efforts in preventing and mitigating coastal eutrophication, as well as nutrient and trace metal pollution, in coastal cities. [ABSTRACT FROM AUTHOR]

The study investigated the effects of cultivating Tridax procumbens in hydroponic conditions with different concentrations of copper ions, aiming to understand the physiological changes and the impact on the biosynthesis of secondary metabolites. The treatments consisted of a completely randomized design, with five increasing concentrations of copper (T0 = 0.235, T1 = 12.5, T2 = 25, T3 = 50, T4 = 100 µmol L−1 of Cu), under controlled conditions for 36 days. Analysis of bioactive compounds in leaves was performed by HPLC–DAD and ESI–MS. Several phenolic compounds, alkaloids, phytosterols and triterpenoids were identified, demonstrating the plant's metabolic plasticity. The highest dose of copper (100 µmol L−1) significantly promoted voacangine, the most predominant compound in the analyses. Notably, 66.7% of the metabolites that showed an increase in concentration, were phenolic compounds. Furthermore, treatments with 12.5 and 25 µmol L−1 of copper were identified as promoting the biosynthesis of phytosterols and triterpenoids. These biochemical adaptations can play a fundamental role in the survival and development of plants in environments contaminated by metals, and from this it is possible to determine cultivation techniques that maximize the biosynthesis of the compound of interest. [ABSTRACT FROM AUTHOR]

In fewer than fifteen years, the study of Ni stable isotopes has advanced from early method development to application of a powerful tool for resolving a long-standing question: why does it appear that output fluxes of Ni from the global oceans far exceed input fluxes? The seawater concentration of Ni, a bioessential trace metal, is almost certainly at steady state on timescales comparable to its residence time of ∼20 kyr, so some of the current flux estimates must be inaccurate. Just as the input and output fluxes should balance, so should the flux-weighted isotopic compositions of the inputs and outputs. Thus, isotopic characterization of inputs and outputs provide an additional constraint on a balanced model of the marine Ni budget. Here, we report on experiments designed to elucidate fractionation mechanisms and magnitudes for sorption of Ni to Mn oxyhydroxide (birnessite), because Mn-rich sediments accumulating on abyssal plains represent the largest sink flux of Ni from seawater to marine sediments. Our results show remarkably large fractionations at low ionic strength (average Δ60/58Ni dissolved-sorbed = +1.38 ‰). Neither closed-system equilibrium trends nor Rayleigh curves fit the data well. Fractionations are even larger at high ionic strength (Δ60/58Ni dissolved-sorbed ranging from +2.0 to +4.0 ‰), and they decrease with experimental duration from 2 d (49 h) to 27 d. The high ionic strength data fit Rayleigh trends well. Here, we use X-ray absorption fine-structure spectroscopy (EXAFS) and results from previous studies to support interpretation of our data as combinations of kinetic and equilibrium isotope effects that vary in their proportional contributions to the total fractionation with time and with surface loading. One important consequence of this study is that none of the experimental results reported thus far, including ours, are directly applicable to building steady-state models of the Ni cycle. Even our longest duration experiments did not achieve equilibrium, which is likely to be manifest in the very slowly accumulating sediments on abyssal plains. Our work constrains further the mechanisms of Ni sorption to birnessite and clearly indicates that determination of equilibrium fractionation in this system, although challenging, will be a crucial step toward resolving the apparent marine Ni imbalance. [ABSTRACT FROM AUTHOR]

A study was carried out to determine the concentration of heavy metals and trace elements in milk and dairy products collected from local farms, supermarkets, or food retailers in the region of Lazio (Central Italy). Persistent exposure to metal contamination is of particular concern for human health, as it can cause different serious disorders. The monitoring of the matrices studied is therefore important, given their high consumption in the daily diet. The elements determined by ICP-MS (Inductively Coupled Plasma – Mass Spectrometry) were lead (Pb), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), nickel (Ni), molybdenum (Mo) and thallium (Tl), for a total of 151 measurements in 98 samples. The results showed that 11.3% of the measurements were quantifiable but below the legal maximum limits (MLs) set by EU regulations. The data obtained may be useful for dietary exposure information, inter-regional comparisons and for planning regional surveillance strategies. [ABSTRACT FROM AUTHOR]

Whether trace metals modify breast density, the strongest predictor for breast cancer, during critical developmental stages such as puberty remains understudied. Our study prospectively evaluated the association between trace metals at Tanner breast stage B1 (n = 291) and at stages both B1 and B4 (n = 253) and breast density at 2 years post‐menarche among Chilean girls from the Growth and Obesity Cohort Study. Dual‐energy x‐ray absorptiometry assessed the volume of dense breast tissue (absolute fibroglandular volume [FGV]) and percent breast density (%FGV). Urine trace metals included arsenic, barium, cadmium, cobalt, cesium, copper, magnesium, manganese, molybdenum, nickel, lead, antimony, selenium, tin, thallium, vanadium, and zinc. At B1, a doubling of thallium concentration resulted in 13.69 cm3 increase in absolute FGV (β: 13.69, 95% confidence interval [CI]: 2.81, 24.52), while a doubling of lead concentration resulted in a 7.76 cm3 decrease in absolute FGV (β: –7.76, 95%CI: −14.71, −0.73). At B4, a doubling of barium concentration was associated with a 10.06 cm3 increase (β: 10.06, 95% CI: 1.44, 18.60), copper concentration with a 12.29 cm3 increase (β: 12.29, 95% CI: 2.78, 21.56), lead concentration with a 9.86 cm3 increase (β: 9.86, 95% CI: 0.73, 18.98), antimony concentration with a 12.97 cm3 increase (β: 12.97, 95% CI: 1.98, 23.79) and vanadium concentration with a 13.14 cm3 increase in absolute FGV (β: 13.14, 95% CI: 2.73, 23.58). Trace metals may affect pubertal breast density at varying developmental stages with implications for increased susceptibility for breast cancer. [ABSTRACT FROM AUTHOR]

Concentrations of one metalloid (As) and eight metals (Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) were determined in tissues (muscle, liver, and kidney) of eight snake species (Bothrops neuwiedi, Crotalus durissus, Dipsas mikanii, Epicrates crassus, Helicops modestus, Micrurus carvalhoi, Oxyrhopus guibei, and Oxyrhopus trigeminus) from Lagoa Santa Karst. Except for Cu and Zn, all other analyzed elements were detected in concentrations within the ranges previously reported for snakes inhabiting polluted areas, emphasizing Hg (specific Hg mean concentrations varied from 0.87 to 9.76 μg g−1 d.w). The highest mean concentrations of all elements except Zn were found in muscle samples of the false corals O. guibei (means ranged from 2.01 [Pb] to 9.76 [Hg]). The highest Zn mean concentration (13.77 μg g−1 d.w) was detected in the kidney of the water snake H. modestus. No significant correlation was found between element concentrations and body size for all species. Significant interorgan differences were observed for As, Cr, Cu, Hg, Mn, Pb, and Zn concentrations in the three tissues in H. modestus. Significant interspecific differences were found in at least one organ for all elements. Significant pairwise differences were found between diet specialist species and between these species and broader diet species, while no significant difference was found between the broader diet species. The bioaccumulation of As and metals in snakes from Lagoa Santa Karst could be associated with natural rock dissolution and erosion processes but also with the wide-scale mining in the region and the increased agriculture and urbanization. [ABSTRACT FROM AUTHOR]

This study integrated hydrochemical analysis, isotopic analysis, the integrated water quality index (IWQI), and the health risk assessment model to analyze hydrochemical characteristics, quality, and nitrate health risks in a typical agricultural and industrial (i.e., Holocene and Pleistocene) simultaneously affected by anthropogenic activities, as well as to explore the recharge mechanisms of the groundwater. The shallow groundwater is mainly Ca-HCO3− and deep groundwater is mainly Na-HCO3− types. In shallow and intermediate aquifers (Holocene), rainfall recharge is seen, but in deep aquifers (Holocene) and the Madhupur tract (Pleistocene), there is no evidence of recent recharge from the stable isotopic (δ2H‰ and δ18O‰) composition of groundwater. Anthropogenic sources significantly impacted the groundwater chemistry of shallow and intermediate aquifers more than geogenic sources. Most metalloids, and metals (As, and Cr, Fe, Ni, Pb, and Mn) and NO3− exceed the WHO-2011 and BD acceptable limit from shallow and intermediate groundwater. PCA analysis revealed the contamination of shallow and intermediate aquifers by metalloids, metals and from various anthropogenic activities. Based on the IWQI, HPI, HEI, and DC, groundwater samples from shallow and intermediate aquifers are unsuitable for oral consumption. The NPI shows that the metalloids, and metals are responsible for groundwater pollution in a descending order of As > Fe > Pb > Ni > Cr > Mn. Health risk assessment indicates oral and dermal consumption of contaminated water from shallow and intermediate aquifers can pose carcinogenic and non-carcinogenic health risks for both the adults and the children. The HQ and HI values of shallow and intermediate groundwater indicates higher non-carcinogenic risk. Carcinogenic risk through oral and dermal consumption follows an order of As > Ni > Cr > Pb and Ni > Cr > As > Pb, respectively. Compared to adults, children are more susceptible to both carcinogenic and non-carcinogenic risks. Potential threats to the health of people living in the study region need immediate attention from the public, government, and the scientific community. [ABSTRACT FROM AUTHOR]

Trace metal pollution of soils is a widespread consequence of anthropogenic activity. Land slugs can be used as bio-indicators of the metals' pollution in the soil, so the present study aimed to determine the metal in the soil and Laevicaulis stuhlmanni land slug tissues by studying its effects on different physiological parameters. Slugs and soil samples were collected from fields in Abu-Rawash, Giza, Egypt. Slugs were identified, and the metals were determined in slug tissues and soil samples. On the other hand, slugs were reared in the laboratory and the new generation was fed on lettuce dipped in 0.027 µg/ml lead (Pb) for 10 days. The results revealed that the soil and slug tissues contained copper, manganese, lead, and zinc; the lead metal bioaccumulation factor was the highest. Also, the results showed that the hemocytes' count, testosterone, and estradiol hormones were significantly decreased. At the same time, the phagocytic index was increased considerably, and some morphological alterations in the granulocytes and hyalinocytes were observed after treatment with 0.027 µg/ml lead compared to untreated slugs. On the other hand, all the oxidative stress parameters were significantly increased in the treated slugs compared with the control. Concerning the histopathological studies, lead caused a rupture, vacuolation, or degeneration in the digestive cells of treated slugs. Finally, it can be concluded that the land slugs were sensitive to lead which was reflected by endocrine disruption, immunotoxicity, and increased oxidative stress parameters with histopathological damages. Hence, Laevicaulis stuhlmanni can be used as a metal accumulation bio-indicator to reflect the metal pollution in the soil. [ABSTRACT FROM AUTHOR]

Water-soluble and trace metal species in fine particulate matter (PM2.5) were determined for indoor and outdoor environments in Doha, Qatar. During the study period, PM2.5 concentrations showed significant variability across several indoor locations ranging from 7.1 to 75.8 μg m−3, while the outdoor mass concentration range was 34.7–154.4 µg m−3. The indoor and outdoor PM2.5 levels did not exhibit statistically significant correlation, suggesting efficient building envelope protection against outdoor PM2.5 pollution. Rather than outdoor sources, human activities such as cooking, cleaning, and smoking were the most significant influence on chemical composition of indoor PM2.5. NH4+ concentration was insufficient to neutralize SO42− indoors and outdoors, indicating the predominant presence of NH4HSO4. The enrichment factors indicated that outdoor Fe, Mn, Co, Cr, and Ni in PM2.5 mostly originated from crustal sources. In contrast, the remaining outdoor trace metals (Cu, Zn, As, Cd, Pb, and V) were mainly derived from anthropogenic sources. The indoor/outdoor concentration ratios revealed significant indoor sources for NH4+ and Cu. The crustal matter, water-soluble ions, and sea salt explained 42%, 21%, and 1% of the indoor PM2.5 mass, respectively. The same groups sequentially constituted 41%, 16%, and 1% of the outdoor PM2.5 mass. [ABSTRACT FROM AUTHOR]

Offshore volcanic activity occurs when an underwater volcano erupts. These volcanoes can be located underwater or on land and can be very dangerous to marine life. The aim of this study is to examine whether the influence of two volcanoes has an effect on the concentrations of metals and trace elements in the Atlantic mackerel Scomber colias in the Canary Islands. For the study, ten specimens of S. colias were obtained from each sampling area in March 2022. Metal concentrations were determined by inductively coupled plasma optical emission spectrophotometry (ICP-OES). The specimens of Scomber colias from the area affected by the Tajogaite volcano (La Palma) showed higher concentrations of all metals and trace elements analyzed than those from the other study areas. The specimens from the area of influence of the Tagoro Volcano (El Hierro) showed the second highest concentration of the elements studied, although this volcanic process is in a state of degassing. [ABSTRACT FROM AUTHOR]

Communities near transportation sources can be impacted by higher concentrations of particulate matter (PM) and other air pollutants. Few studies have reported on air quality in complex urban environments with multiple transportation sources. To better understand these environments, the Kansas City Transportation and Local-Scale Air Quality Study (KC-TRAQS) was conducted in three neighborhoods in Southeast Kansas City, Kansas. This area has several emissions sources including transportation (railyards, vehicles, diesel trucks), light industry, commercial facilities, and residential areas. Stationary samples were collected for 1-year (October 24, 2017, to October 31, 2018) at six sites using traditional sampling methods and lower-cost air sensor packages. This work examines PM less than 2.5 μm in diameter (PM2.5), black carbon (BC), and trace metals data collected during KC-TRAQS. PM2.5 filter samples showed the highest 24-h mean concentrations (9.34 μg/m3) at the sites located within 20–50 m of the railyard. Mean 24-h PM2.5 concentrations, ranging from 7.96 to 9.34 μg/m3, at all sites were lower than that of the nearby regulatory site (9.83 μg/m3). Daily maximum PM2.5 concentrations were higher at the KC-TRAQS sites (ranging from 25.31 to 43.76 μg/m3) compared to the regulatory site (20.50 μg/m3), suggesting short-duration impacts of localized emissions sources. Across the KC-TRAQS sites, 24-h averaged PM2.5 concentrations from the sensor package (P-POD) ranged from 3.24 to 5.69 µg/m3 showing that, out-of-the-box, the PM sensor underestimated the reference concentrations. KC-TRAQS was supplemented by elemental and organic carbon (EC/OC) and trace metal analysis of filter samples. The EC/OC data suggested the presence of secondary organic aerosol formation, with the highest mean concentrations observed at the site within 20 m of the railyard. Trace metals data showed daily, monthly, and seasonal variations for iron, copper, zinc, chromium, and nickel, with elevated concentrations occurring during the summer at most of the sites. Implications: This work reports on findings from a year-long air quality study in Southeast Kansas City, Kansas to understand micro-scale air quality in neighborhoods impacted by multiple emissions sources such as transportation sources (including a large railyard operation), light industry, commercial facilities, and residential areas. While dozens of studies have reported on air quality near roadways, this work will provide more information on PM2.5, black carbon, and trace metals concentrations near other transportation sources in particular railyards. This work can also inform additional field studies near railyards. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate bottom sediments quality in 32 stations at Santos Estuarine Channel, home to one of the main international ports in South America, and to the Cubatão industrial complex, the most important petrochemical and metallurgical area in Brazil. Sediment quality was approached through contamination (mCd), ecological (PEI, SQG-Q, PLI) and geoaccumulation (Igeo) indices. Phosphorus Enrichment Index (PEI) revealed phosphorus enrichment, with potential risk to biota regarding eutrophication effects. Index of geoaccumulation (Igeo) revealed accumulation of Pb, Cu, Zn, Ni, Cr, Cd and As, all reaching class 6 of contamination, pointing to extreme contamination. Contamination index revealed null to moderate contamination for most stations. Pollution Load Index (PLI) revealed no contamination, and Sediment Quality Guideline (SQG-Q) pointed to moderate impact, suggesting risk to benthic biota. The mud content of the samples did not correlate with arsenic, phosphorus and trace metals. Organic matter seemed to be the main carrier of these elements in the system. Results revealed accumulation of trace metals and As in bottom sediments of Santos estuarine channel, which can be used to develop guidelines for monitoring these pollutants in anthropogenic activities along the harbor area. [ABSTRACT FROM AUTHOR]

Background: When studying metallophytes and hyperaccumulator plants, it is often desired to assess the level of tolerance of a specific trace metal/metalloid in a putative tolerant species, to determine root and shoot accumulation of the trace metal/metalloid of interest, or to establish whether a trace metal/metalloid has an essential function. The use of hydroponics has proven to be a powerful tool in answering such questions in relation to the physiological regulation of metal/metalloids in plants. Carefully designing experiments requires considering nutrient solution formulation, dose rate regime, and environmental conditions, but this is often overlooked. Aims: This review aims to bring together key information for hydroponics studies in physiological, evolutionary, and genetics/molecular biological research of trace metal/metalloid tolerance and accumulation in plants, focussing on metallophytes and hyperaccumulator plants. Conclusions: It is not possible to define a 'universal' nutrient solution that is both sufficient and non-toxic for all plants, although it is often possible, dependent on plant species under study and the research question to be addressed, to 'adapt' commonly used 'standard formulations'. Well-designed and executed hydroponics experiments can yield powerful insights in the regulation of essential and toxic metal/metalloid trace elements, and this extends far beyond hyperaccumulator plants. [ABSTRACT FROM AUTHOR]

The intensive use, development, and expansion of the road network is expanding the zones of direct impact of road transport on forest ecosystems. Issues related to the mobility of trace elements in forest ecosystems along motorways are very important due to the numerous environmental risks associated with the excessive accumulation of metals, the ability to migrate and accumulate in plants and animals, and the risk of transferring these elements to higher trophic levels. The aim of this article was therefore to determine the impact of road traffic on the basis of contents of trace metals Cd, Cr, Cu, Ni, Pb, and Zn and to describe the relationship of these contents in moss gametophytes and blueberry leaves taken in the vicinity of an existing and variously expanded expressway (S7, Poland, Europe). Analyses of transport impacts included the effects of distance and time of pollutant deposition and road transport on habitat and stand conditions. The highest contents of Cd, Cr, Cu, Ni, Pb, and Zn in moss tissues were found in fir stands and the contents were, respectively, 0.36 mg·kg−1, 5.91 mg·kg−1, 12.5 mg·kg−1, 3.26 mg·kg−1, 8.82 mg·kg−1, and 55.28 mg·kg−1. Mosses showed the best bioindication capacity of all of the studied ecosystem elements. The Pb, Zn, Cr, Cu, and Ni contents were particularly markedly elevated in moss tissues relative to non-anthropopressured areas and dependent on distance from the emitter (road). Blueberry proved to be a less useful bioindicator, as the contents of Cd, Cr, Cu, Ni, Pb, and Zn found were similar to the data from non-anthropopressured areas and were, respectively, 0.09 mg·kg−1, 0.98 mg·kg−1, 7.12 mg·kg−1, 2.49 mg·kg−1, 1.18 mg·kg−1, and 15.91 mg·kg−1 in fir stands and 0.04 mg·kg−1, 0.47 mg·kg−1, 6.63 mg·kg−1, 1.65 mg·kg−1, 0.72 mg·kg−1, and 17.44 mg·kg−1 in pine stands. [ABSTRACT FROM AUTHOR]

Dinitrogen (N2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N2 fixation rates (up to 13.96 nmol N l−1 d−1) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections. [ABSTRACT FROM AUTHOR]

Iron speciation has emerged as a robust proxy for discerning oceanic redox conditions; nonetheless, it is subject to certain limitations. Specifically, the applicability of the degree of pyritization is contingent upon the presence of unequivocal evidence of an anoxic water column and its discriminatory capacity is limited to distinguish between ferruginous (anoxic) and euxinic conditions. This study highlights that through the integration of redox‐sensitive trace metal enrichment data with Fe‐speciation data, the depositional redox conditions for marine sediments can be established with greater certainty. Recently, a set of dedicated geological reference materials (BHW and WHIT) have been developed for validating the Fe‐speciation analytical results for redox reconstruction studies; however, to the best of our knowledge, these reference materials are not characterized for trace and rare earth elements (REEs). In this connection, the BHW (oxic) and WHIT (anoxic) reference materials are measured for major, trace and REEs. After careful statistical considerations for these reference standards, a complete set of trace and REEs is reported. Furthermore, considering BHW and WHIT as oxic and anoxic end‐members, respectively, the utility of trace metal enrichment and Fe‐speciation data in combination has been discussed. The trace and REE concentrations of BHW and WHIT reported in this study will enhance their applicability as a reference material to understand ocean chemistry and the oxidation state of the ancient oceans. [ABSTRACT FROM AUTHOR]

Tea is the most consumed beverage in the world after water and contains heavy metals and trace elements that may cause potential negative effects on health. Aluminium (Al) concentrations in black, green, and white tea with different infusion times and teapot materials were evaluated in this study. Commercially available tea samples were brewed in 5 different teapots, consisting of aluminium, copper, glass, steel, and porcelain materials for 5, 10, and 15 min. Al concentrations in tea samples were determined by high-performance liquid chromatography with a fluorescence detector. Al concentrations in tea samples were in the range of 38.46 ± 5.08–844.75 ± 10.86 µg/L. Both teapot type (p < 0.001) and infusion time (p < 0.001) significantly influenced Al concentrations in tea samples. The interaction between tea type, teapot material, and infusion time was statistically significant (p < 0.001). The hazard ratio was less than 1 for black and white tea infusions except for one sample whereas it was greater than 1 for green tea. These data suggest that green tea consumption might be a potential risk factor for Al exposure. [ABSTRACT FROM AUTHOR]

Naturally-occurring thorium isotopes and corresponding Ra-Th disequilibrium in aquatic system are good tracers for particle dynamic processes. Here we reported a case study on the occurrence of 228Thex-228Ra disequilibrium in sediments of a shallow estuary-coastal bay system (Zhangjiang Estuary-Dongshan Bay). 228Ra activity concentration in saline water and 228Ra and 228Th activities in the surface sediments were measured and we found 228Ra's non-conservative behavior in saline water and the existence of excess 228Th (228Thex = 228Th-228Ra) in surficial sediments at all the stations. Spatially, 228Thex gradually decreased from the Zhangjiang Estuary (16 Bq/kg) to the inner Dongshan Bay (8–11 Bq/kg), which is consistent with the variation trend of 228Ra activity concentration in seawater. This consistency explained the reason for the occurrence of 228Ra-228Th disequilibrium (or called "228Thex occurrence") in the surface sediments. Because 228Ra activity concentration is very high in estuarine water, and 228Th continues to decay from 228Ra, and the newly formed 228Th is quickly cleared by suspended particles in the water and subsequently settles down to the seabed sediments. Based on a constructed simple irreversible scavenging model, the residence time of 228Thex was constrained to be 15–30 days in the estuary and to be 5–11 days in the inner bay. These results show that Th and other similarly particle-reactive trace metals will be scavenged rapidly from the water column of shallow estuary-bay systems. [ABSTRACT FROM AUTHOR]

The current study assessed the accumulation rate of four heavy metals (i.e., Cu, Zn, Cd, and Pb) in water, sediment, and tissues of the freshwater mussels Unio tigridis. The trace metal concentrations in water, sediment, and tissues showed the following decreasing trend: Zn (mean W: 31.08 mg/L; mean S: 10.495 mg/g; and mean T:4.925 mg/g) > Cu (mean W: 6.538 mg/L; mean S: 46.712 mg/g; and mean T: 17.127) > Pb (mean W: 31.08 mg/L; mean S: 10.495 mg/g; and mean T:4.925 mg/g) > Cd (mean W: 0.277 mg/L; mean S: 0.77 mg/g; and mean T: 0.674 mg/g), and the toxic metal concentrations exceeded the recommended acceptable limits. Necrosis, blood cell infiltration, atrophy, epithelium damage, brown cells, and fat agglomerates were the most common histological changes found in the digestive glands of mussels. These histopathological lesions can be considered reliable biomarkers in biomonitoring programs for heavy metal contamination in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Fluvial sediment analysis and water quality assessment are useful to identify anthropic and natural sources of pollution in rivers. Currently, there is a lack of information about water quality in the Pixquiac basin (Veracruz state, Mexico), and this scarcity of data prevents authorities to take adequate measures to protect water resources. The basin is a crucial territory for Xalapa, the capital city of Veracruz state, as it gets 39% of its drinkable water from it. This research analyzed 10 physicochemical parameters and 12 metal concentrations in various rivers and sources during two seasons. Dissolved metals presented average concentrations (µg/L): Al (456.25) > Fe (199.4) > Mn (16.86) > Ba (13.8) > Zn (7.6) > Cu (1.03) > Pb (0.27) > As (0.12) > Ni (0.118) (Cd, Cr and Hg undetectable). Metals in sediment recorded average concentrations (ppm): Fe (38575) > Al (38425) > Mn (460) > Ba (206.2) > Zn (65.1) > Cr (29.8) > Ni (20.9) > Cu (16.4) > Pb (4.8) > As (2.1) (Cd and Hg undetectable). During the rainy season, Water Quality Index (WAWQI) classified stations P17 and P18's water as "unsuitable for drinking" with values of 110.4 and 117.6. Enrichment factor (EF) recorded a "moderate enrichment" of Pb in sediment in P24. Pollution was mainly explained by wastewater discharges in rivers but also because of erosion and rainfall events. Statistical analysis presented strong relationships between trace and major metals which could explain a common natural origin for metals in water and sediment: rock lixiviation. [ABSTRACT FROM AUTHOR]

Fish as seafood is a bioindicator for chemical substances like trace metals in the water systems that accumulate in fish bodies. Fe and Zn as essential and Pb, Ni, and Cd as heavy metals were quantitatively analyzed in fish muscle samples by an atomic absorption spectrophotometer (Perkin Elmer, Model AAnalyst-700). Fe and Zn's results agreed with the food quality guidelines. Fe was the highest in the range of 2.6–9.4 in mg kg−1. The Zn content indicates the contribution of anthropogenic agents through the food chain. Ni > Pb > Cd was found in marine fish species and Pb > Ni > Cd in freshwater fish. The results have been explored for source appraisal of bioaccumulated trace metals and categorized selected marine and freshwater species based on characteristics (like life cycle and habitats) by applying multivariate principal component analysis to risk assessment parameters. The Pearson correlation coefficients were applied to the risk assessment parameters for interdependencies of metals. Interestingly, synchronized outcomes were obtained with trace metal data. The study results were interpreted in the context of the fish type, habitat, surroundings, feed, life cycle, etc. The living habitats strongly affect trace metal accumulation, target hazard quotient (THQ), and target cancer risk (TR) attributes. The fishermen's community was at higher risk for carcinogenic effects than other seafood consumers. Overall, determinations for fish species were under safe limits as described by international regulatory bodies (FAO, WHO, ANHMRC, WAA). [ABSTRACT FROM AUTHOR]

This study investigated the correlation between the levels of chromium (Cr), lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu) in surface sediment samples and those in the total soft tissues of the mussel Mytilus.galloprovincialis, collected off the northern Moroccan coast in the Mediterranean. The objective was to examine the accumulation patterns of these heavy metals in M. galloprovincialis relative to their concentrations in the sediment. Detailed sampling of sediments and Mytilus galloprovincialis mussels were carried out at three specific stations to measure trace metal concentrations. A perfect correlation was observed for Pb levels between the mussel tissues and sediment. The sampling methods were carefully planned to ensure data accuracy and consistency, following strict protocols to reduce contamination and maintain sample integrity. In contrast, Cr showed only a weak correlation. The correlations for the other trace metals (Cd, Zn, and Cu) varied from strong to weak and were both positive and negative, but none were statistically significant. These findings underscore the potential of M. galloprovincialis as an effective biomonitoring species for Pb. However, additional research and more comprehensive analyses are necessary to establish firmer conclusions regarding the correlations for the other metals. [ABSTRACT FROM AUTHOR]

In vitro incubations using natural marine communities can provide insight into community structure and function in ways that are challenging through field observations alone. We have designed a minimal metal incubation system for controlled and repeatable experimentation of microbial communities. The systems, dubbed Pelagic Ecosystem Research Incubators (PERIcosms), are 115 L, conical tanks designed to sample suspended, settled, and wall associated material for month long periods. PERIcosms combine some of the ecological advantages of large volume mesocosm incubations with the experimental ease and replication of bottle incubations, and their design is accessible for use by researchers without specialized training or travel to a designated incubation facility. Here, we provide a detailed description for the construction and implementation of PERIcosms and demonstrate their potential to promote replicable, diverse communities for several weeks under clean conditions using time‐series results from two field experiments. One field experiment utilized coastal waters collected from Santa Catalina Island, CA and the other oligotrophic waters collected offshore of Honolulu, HI. Biomass metrics (chlorophyll a and particulate carbon) along with 16S/18S DNA based community composition assessments were conducted to show that communities contained within PERIcosms remained alive and diverse for several weeks using a semi‐continuous culturing approach. We detail trace metal clean techniques that can be used to minimize external contamination, particularly for low dissolved iron environments. PERIcosms have the potential to facilitate natural community incubations which are needed to continue advancing our understanding of microbial ecology and geochemistry. [ABSTRACT FROM AUTHOR]

Surface soils in urban regions play a crucial role in controlling regional climatic patterns and sustaining ecological equilibrium. This study evaluates the contamination status, distribution patterns and ecological risks of trace metals (TMs) in the soil. Twenty-two sets of surface soils were collected and analyzed using X-ray fluorescence spectrometry, to estimate the levels of TMs, including As, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Y, and Zn. The study reveals a high degree of spatial variability in the distribution of TMs, attributable to the influence of various contamination sources. Simultaneously, descriptive statistical analyses unveil that contents of Cu, V, Co, Ni, Cr, Ba, Y, Zn and Sr in the soils were higher than the local background values. Furthermore, most of the surface soil sampling demonstrated moderate to heavily pollution with a few indicating light pollution. The northern, north-western and central parts in the surveyed zone, particularly in the vicinity of Kabelmal, Naimatabad, and Waddi County, were found to be heavily contaminated. The presence of As, Pb, and Zn was primarily influenced by anthropogenic sources, including agricultural and traffic emissions, while Cr and Y were mainly due to industrial emissions. In addition, Ni, Cr and Co were largely attributed to human activities. This provides fundamental information on TMs in surface soils and underscores the necessity for long-term monitoring to safeguard soil and environmental health. [ABSTRACT FROM AUTHOR]

Metal contamination of the environment poses a significant threat to human health and can cause significant damage to aquatic ecosystems. Danio rerio was exposed to Sorocaba River water for 96 h from two different sites in summer (S) and winter (W). Concentrations of Al, Cd, Cu, Mn and Zn were determined in the exposure water and in sediment. At the end of the exposure, the concentrations of Al, Cu and Mn at the Ibiúna point (P1) and Mn at the Itupararanga point (P2) decreased compared to the initial concentrations in the water. In summer and winter, the highest concentrations of Cu and Mn were found in the sediment. Exposure to the Sorocaba River water caused various responses both in summer and winter. For example, GPx decreased in winter, Glutathione S-Transferase (GST) increased in summer, and Nitric Oxide Synthase (NOS) decreased in both seasons in the viscera. In winter, SOD Superoxide Dismutase (SOD) increased, while GPx and GST (winter) decreased in muscle; regarding viscera carbonyl proteins, there was an increase in the summer at P2. Acetylcholinesterase activity decreased in the brain in winter at P2 and NOS decreased in the summer-exposed groups and increased in the winter P2-exposed group. Lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) decreased in viscera (S, P1) and increased in muscle (S, P1 and P2). The glucose and triglycerides increased in muscle, both in summer and winter. Correlation analysis revealed associations between biomarkers from different organs. These alterations suggest that the fish experienced oxidative stress in response to exposure to the Sorocaba River, contaminated with metals, highlighting their vulnerability to environmental pollutants. [ABSTRACT FROM AUTHOR]

Nowadays, trace metal contamination within urban atmospheres is a significant and concerning global issue. In the present study, two synanthropic bird species, namely, the feral pigeon (Columba livia f. domestica) and the rook (Corvus frugilegus), were employed as bioindicators to assess the atmospheric trace metal pollution in Iasi City, Romania. The concentrations of Ni, Pb, Cd, Co, Cr, and Cu were determined through high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF-AAS) of various tissues, including the liver, kidney, lung, heart, muscle, and bone, of feral pigeons and rooks collected in Iasi City. The order of trace metal concentrations in the tissues of feral pigeons and rooks in Iasi City was similar: Cu > Pb > Ni > Cd > Cr > Co. However, trace element values in most tissues were higher in the rook samples than in feral pigeon ones, except for Co, which had elevated levels in feral pigeon renal and cardiac tissues, and Cu, which registered the highest concentrations in feral pigeon liver and kidney tissues. While not statistically significant, Pb concentration values in the PM10 fraction of atmospheric particles positively correlated with Pb concentrations in rook kidney samples (p = 0.05). The concentration levels of Cd, Pb, and Ni in the PM10 fraction of air particles showed a positive correlation with Cd levels in the samples of pigeon heart and rook liver, kidney, and heart, Pb levels in the samples of pigeon kidney, heart, and muscle and rook liver and bone, and Ni levels in the samples of pigeon liver, kidney, and bone and rook liver, muscle, and bone, respectively. [ABSTRACT FROM AUTHOR]

This review is a comprehensive overview of recent advancements in underwater in situ heavy metal voltammetric analyzers (UIHVAs). It explores various types of in situ voltammetric analyzers, including the voltammetric in situ profiling system, submersible integrated multi-channel trace metal sensing probes, vibrating gold microwire electrode voltammetric analyzers, and electrochemical analyzers designed for on-site flow measurements. It also covers electrochemical sensors based on flexible liquid crystal polymers, deep-sea mercury sensors, and other in situ electrochemical analyzers. This review systematically examines the research and development progress of microelectrode arrays, screen-printed, carbon, bismuth, antimony, and lab-on-a-chip electrodes. The final section looks at key trends in the research and development of voltammetric analyzers, highlighting the exploration of novel working electrodes, the integration of smart monitoring and data analysis technologies, and the promotion of interdisciplinary collaboration and innovation. From a global perspective, in situ heavy metal voltammetric analysis technology has demonstrated significant applicability in various fields, such as environmental monitoring, marine science, and biogeochemistry. This technology holds considerable potential for further development. However, extensive research and continuous improvement are required to improve detection performance. We are convinced that with continued technological advances and dedicated research efforts, these challenges can be overcome and will pave the way for the widespread application of UIHVAs. [ABSTRACT FROM AUTHOR]

We study of the properties of a new class of circumgalactic medium absorbers identified in the Ly α forest: 'Strong, Blended Lyman-α' (or SBLA) absorption systems. We study SBLAs at 2.4 < z < 3.1 in SDSS-IV/eBOSS spectra by their strong extended Ly α absorption complexes covering 138 |$\, \, {\rm km}\, {\rm s}^{-1}$| with an integrated |$\log (N_{\rm H\, {\small I}}/\mathrm{cm}^{-2}) =16.04$| |$\substack{+0.05 \\ -0.06}$| and Doppler parameter b = 18.1 |$\substack{+0.7 \\ -0.4}$| |$\, \, {\rm km}\, {\rm s}^{-1}$|⁠. Clustering with the Ly α forest provides a large-scale structure bias of b = 2.34 ± 0.06 and halo mass estimate of |$M_h \approx 10^{12}\, h^{-1}\, {\rm M_{\odot }}$| for our SBLA sample. We measure the ensemble mean column densities of 22 metal features in the SBLA composite spectrum and find that no single-population multiphase model for them is viable. We therefore explore the underlying SBLA population by forward modelling the SBLA absorption distribution. Based on covariance measurements and favoured populations we find that ≈25 per cent of our SBLAs have stronger metals. Using silicon only we find that our strong metal SBLAs trace gas with a log (n H/cm−3) > −2.40 for T = 103.5 K and show gas clumping on <210 parsec scales. We fit multiphase models to this strong subpopulation and find a low ionization phase with n H = 1 cm−3, T = 103.5 K, and [X/H] = 0.8, an intermediate ionization phase with log (n H/cm−3) = −3.05, T = 103.5 K and [X/H] = −0.8, and a poorly constrained higher ionization phase. We find that the low ionization phase favours cold, dense super-solar metallicity gas with a clumping scale of just 0.009 parsecs. [ABSTRACT FROM AUTHOR]