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Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive, hindering accurate assessment on environmental risks and effectiveness of remediation strategies. This study evaluated the feasibility of European Community Bureau of Reference (BCR) sequential extraction, Ca(NO3)2 extraction, and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime, magnesium hydroxide, corn stover biochar, and calcium dihydrogen phosphate. Moreover, the enriched isotope tracing technique (112Cd and 206Pb) was employed to evaluate the aging process of newly introduced Cd and Pb within 56 days' incubation. Results demonstrated that extractable pools by BCR and Ca(NO3)2 extraction were little impacted by amendments and showed little correlation with soil pH. This is notable because soil pH is closely linked to metal availability, indicating these extraction methods may not adequately reflect metal availability. Conversely, water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH (Pearson's r: -0.908 to -0.825, P < 0.001), suggesting water extraction as a more sensitive approach. Furthermore, newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools. Additionally, water-soluble concentrations of essential metals were impacted by soil amendments, raising caution on their potential effects on plant growth. These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability, which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.

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Controlling heavy metal pollution in agricultural soil has been a significant challenge. These heavy metals seriously threaten the surrounding ecological environment and human health. The effective assessment and remediation of heavy metals in agricultural soils are crucial. These two aspects support each other, forming a close and complete decision-making chain. Therefore, this review systematically summarizes the distribution characteristics of soil heavy metal pollution, the correlation between soil and crop heavy metal contents, the presence pattern and migration and transformation mode of heavy metals in the soil-crop system. The advantages and disadvantages of the risk evaluation tools and models of heavy metal pollution in farmland are further outlined, which provides important guidance for an in-depth understanding of the characteristics of heavy metal pollution in farmland soils and the assessment of the environmental risk. Soil remediation strategies involve multiple physical, chemical, biological and even combined technologies, and this paper compares the potential and effect of the above current remediation technologies in heavy metal polluted farmland soils. Finally, the main problems and possible research directions of future heavy metal risk assessment and remediation technologies in agricultural soils are prospected. This review provides new ideas for effective assessment and selection of remediation technologies based on the characterization of soil heavy metals.

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To accurately assess the bioavailability risk of heavy metals (HMs) in a representative polymetallic mining region, we undertook an exhaustive analysis of Cu, Pb, Ni, Co, Cd, Zn, Mn, and Cr in soils from diverse land-use types, encompassing agricultural, forest, residential, and mining areas. We employed speciation analysis methods and a modified risk assessment approach to ascertain potential ecological threats posed by the HMs. Our findings reveal that both the total potential ecological risk and the modified bioavailability risks are most pronounced in the soil of the mining area. The modified bioavailability threats are primarily caused by Pb, Ni, Cd, and Co. Although the total potential ecological risk of Cu is high in the local soil, the predominance of its stable forms reduces its mobility, thereby mitigating its detrimental impact on the ecosystem. Additionally, medium modified bioavailability risks were identified in the peripheries of agricultural and forest areas, potentially attributable to geological processes and agricultural activities. Within the urban district, medium risks were observed in residential and mining areas, likely resulting from mining, metallurgy, industrial operations, and traffic-related activities. This study provides critical insights that can assist governmental authorities in devising targeted policies to alleviate health hazards associated with soils in polymetallic mining regions.

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Advances in green engineering and technology have revealed a number of environmentally acceptable alternatives for water purification. In line with this, recent advances in biosorption of pollutants from aqueous solutions using animal biowaste-based activated carbon (AC) are reported herein. Apart from the fish scale-derived AC which is extensively documented, animal bones, among the rest others, have been studied most widely, followed by hair and feathers. Out of the various target water pollutants, removal of heavy metals has been mostly studied. Majority of the reports showed the Freundlich isotherm and pseudo second order as the best fit. Few investigations on the thermodynamics of the adsorption studies and reports on the Gibbs free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) have also been discussed in this report. It has been concluded that while plant-based AC has gained wide interest, the same is not true for the animal-based counterpart albeit the latter's potential for high sorption efficiency as seen in the present report.

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Preventing impending heavy metal pollution in arable soil is crucial for ensuring food security and avoiding challenging remediation. The key to effective prevention strategies lies in proactive identifying currently unpolluted regions that are susceptible to future pollution, which current methods, predicated on the assessment of static pollution status, inadequately characterize the potential accumulative changes in soil heavy metals. In this paper, we proposed a framework for identifying priority areas based on the discrepancy between pollution status and accumulative risk, by considering the specific factors that influence heavy metal accumulation in soil. We applied this framework to a region of Xiangtan County to pinpoint priority areas for preventing impending pollution. The result revealed certain areas exhibited a relatively higher accumulative risk of heavy metal pollution, despite not having reached severe pollution levels for the heavy metals Arsenic (As), Cadmium (Cd), Chromium (Cr), Mercury (Hg), and Lead (Pb), among which the area ratio reached nearly 6 %, 36 %, 1 %, 3 %, 4 %, respectively. The priority areas for preventing Cd pollution were primarily concentrated in the mid-southern, mid-western, and eastern regions, while that of the other four heavy metals were predominantly distributed in the mid-northern regions with varying continuous ranges. Moreover, we prioritized the main pollution risks for comprehensive prevention in the following order: Cd, As, Pb, Hg, and Cr, and investigated the key factors contributing to the pollution of these heavy metals. The insights presented in this study have significant implications for soil environmental quality management, offering valuable guidance for implementing precise measures to prevent heavy metal pollution and efficiently control pollution sources.

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The pollution of heavy metals and harmful elements in traditional Chinese medicine is one of the main problems that hinder the internationalization of traditional Chinese medicine. At present, major developed countries have incorporated elemental residues into drug risk assessment to ensure drug quality and safety, while China's drug risk assessment system is still in its infancy. In recent years, China has made efforts to improve the risk assessment system of traditional Chinese medicine. Researchers have reported the risk assessment of heavy metals and harmful elements in traditional Chinese medicine, aiming to evaluate the quality and safety of traditional Chinese medicine and promote the integration of traditional Chinese medicine with international standards. This study reviews the research reports in recent years, compares the pharmacopoeia standards of major developed countries, pinpoints the similarities and differences between different drugs in terms of hazard identification, hazard characteristics, and assessment methods, and discusses the possible problems and development directions of the risk assessment system of traditional Chinese medicine. This review is expected to improve the limit standards of traditional Chinese medicine elements and the risk assessment system of traditional Chinese medicine, thus providing support for enhancing the international competitiveness of traditional Chinese medicine products.

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Microplastics (MPs) pollution has raised serious environmental concerns due to its widespread generation and discharge across global ecosystems. It is estimated that approximately 400 million metric tons of plastic are produced annually, with 54% ending up as waste. The MPs account for a significant portion of this pollution. These MPs interact with heavy metals (HMs) in terrestrial ecosystems, such as cadmium (Cd), lead (Pb), and arsenic (As), which are introduced through various industrial activities at rates of thousands of tons per year. Such interactions may cause synergistic or antagonistic effects on plants. Recent studies suggest that MPs and HMs exposure impacts various physiological and biochemical pathways in plants, thereby increasing the toxicity symptoms. However, the existing scholarly understanding of the coupled effect of HMs and MPs on plants is limited, highlighting the need to explore these complex dynamics further. Through a comprehensive analysis of current research, this review underscores various pathways of MPs and HMs infiltration mechanisms, detailing their penetration, translocation, and bioaccumulation within plants. The physiological and biochemical effects of both pollutants on plants are deliberated individually and in combination. The review reveals that the co-existence of these contaminants results in a multifaceted environmental challenge, affecting overall plant growth, yield, and quality in ways that differ from individual exposure. Building on recent advancements, this article is expected to delineate the complex interactions between MPs, HMs, and plants and enhance the current understanding of the intricate interplay between them.

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Gold mining, even under strict environmental regulations, inevitably causes environmental impacts and liabilities. To address this, the study proposes a framework for environmental zoning around gold mines based on the distribution of potentially toxic elements (PTEs), pollution indices, and bioindicators. Soil samples were collected from municipalities affected by gold mining projects, and concentrations of As, Cd, Pb, and Cr were measured. Then, the Pollution Load Index (PLI) was calculated. A plant model was used for the biomonitoring of PTEs, and the Plant Vigor Index (PVI) was determined. Finally, environmental zoning was proposed through geospatial analysis combining PTEs, PLI, and PVI values. The concentrations of PTEs were as follows: As ranged from 1.7 to 892, Cd from 0.1 to 65.2, Pb from 18.5 to 2345, and Cr from 5.4 to 118.4. Spearman's rank correlation showed significant relations (ρ > 0.76) between bioindicators and PTE concentrations and PLI. The PVI correlated significantly with PTE concentrations (ρ - 0.41 to - 0.67) and PLI (ρ - 0.65). The municipalities were categorized into three zones: highly contaminated, moderately contaminated, and minimally contaminated. Overall, the environmental zoning maps serve as a management tool for environmental monitoring.

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The removal of pollutants, including heavy metals, from the aquatic environment is an urgent problem worldwide. Actively developing nanotechnology areas is becoming increasingly important for solving problems in the field of the remediation of aquatic ecosystems. In particular, methods for removing pollutants using nanoparticles (NPs) are proposed, which raises the question of the effect of a combination of NPs and heavy metals on living organisms. In this work, we investigated the role of CuO-NPs in changing the toxicity of Cd and Pb salts, as well as the bioaccumulation of these elements in a culture of the microalga Desmodesmus communis. It was found that CuO-NPs at concentrations of 10, 100, and 1000 µg L-1 had no effect on the viability of microalgae cells. On the 14th day of the experiment, Cd at a concentration of 1 mg L-1 reduced the viability index by 30% and, when combined with CuO-NPs, by 25%, i.e., CuO-NPs slightly reduced the toxic effect of Cd. At the same time, in this experiment, when CuO-NPs and Cd were used together, the level of oxidative stress increased, including on the first day in mixtures with 1 mg L-1 Cd. Under the influence of Pb, the cell viability index decreased by 70% by the end of the experiment, regardless of the metal concentration. The presence of CuO-NPs slightly reduced the toxicity of Pb in terms of viability and reactive oxygen species (ROS). At the same time, unlike Cd, Pb without NPs caused ROS production on the first day, whereas the addition of CuO-NPs completely detoxified Pb at the beginning and had a dose-dependent effect on mixtures at the end of the experiment. Also, the introduction of CuO-NPs slightly reduced the negative effect of Pb on pigment synthesis. As a molecular mechanism of the observed effects, we prioritized the provocation of oxidative stress by nanoparticles and related gene expression and biochemical reactions of algae cells. Analysis of the effect of CuO-NPs on the Cd and Pb content in microalgae cells showed increased accumulation of heavy metals. Thus, when algae were cultured in an environment with Cd and CuO-NPs, the Cd content per cell increased 4.2 times compared to the variant where cells were cultured only with Cd. In the case of Pb, the increase in its content per one cell increased 6.2 times when microalgae were cultured in an environment containing CuO-NPs. Thus, we found that CuO-NPs reduce the toxic effects of Cd and Pb, as well as significantly enhance the bioaccumulation of these toxic elements in the cells of D. communis microalgae. The results obtained can form the basis of technology for the nanobioremediation of aquatic ecosystems from heavy metals using microalgae.

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This study investigated the efficacy of incorporating nitric oxide (NO; 10 µM) and ascorbic acid (Asc; 10 µM) into the culture medium to confer cadmium (Cd; 5 µM) tolerance in thyme (Zataria multiflora). The phytotoxicity of Cd resulted in a decrease in shoot biomass, which NO or Asc mitigated. Adding Asc and NO to the culture medium was associated with substantial DNA hypomethylation. The NO + Cd and Asc + Cd treatments were accompanied by an increase in the unmethylation percentages, about 3-fold higher than the control. The hemi-methylation percentages in the Asc-supplemented seedlings also displayed an upward trend. The transcriptional upregulation in the γ-terpinene synthase (TPS) gene resulted from the applied elicitors, especially NO. In response to the NO and Asc treatments, the transcription of two cytochrome P450 monooxygenase genes (CYP71D178 and CYP71D180) went up. Incorporating Asc or NO into the culture medium enhanced the concentrations of proline, carvacrol, and thymol metabolites. Employing NO or Asc mitigated the 43% decrease in protein content due to the Cd cytotoxicity. The NO and Asc applications improved the activity of the phenylalanine ammonia-lyase (PAL) enzyme. NO and Asc utilization increased the accumulation of flavonoids. NO and Asc also up-regulated the activities of two enzymatic antioxidants (catalase and peroxidase). Collectively, this study provided novel insight into how Asc or NO confers Cd tolerance by epigenetically remodeling DNA methylation, transcriptionally up-regulating terpenoid and phenylpropanoid metabolism, increasing proline concentration, and improving antioxidants.

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In the field of soil remediation, the importance of bioavailability of pollutants has not received adequate attention, leading to the excessive application of remediation measures. Therefore, to ensure the safe use of farmland soil, a scientific method is needed to assess labile contaminants and their translocation in plants. To evaluate soil remediation effect based on bioavailability, the concentrations of these heavy metals in soil were analyzed using by the method for total metal content, the Community Bureau of Reference (BCR) extraction, and the diffusive gradients in thin films (DGT) technique. The results reveal that the correlation coefficients between metal concentrations measured by DGT and those accumulated in rice grains are the highest (Cr-R2 = 0.8966, Pb-R2 = 0.9045). However, the capability of method for total metal content to evaluate the remediation effect of heavy metals is very limited. In contrast, although Cr and Pb measured by BCR show a high correlation with HMs in rice plants, the method still falls short in precisely assessing bioavailability. Significantly, DGT proves to be more effective, successfully distinguishing the remediation effects of different treatments. Generally, DGT offers a more accurate and simpler assessment method, underscoring its practical significance for monitoring soil remediation and environmental management.

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The increasing demand for mineral resources has generated mine tailings with heavy metals (HM) that negatively impact human and ecosystem health. Therefore, it is necessary to implement strategies that promote the immobilization or elimination of HM, like phytoremediation. However, the toxic effect of metals may affect plant establishment, growth, and fitness, reducing phytoremediation efficiency. Therefore, adding organic amendments to mine tailings, such as biochar, can favor the establishment of plants, reducing the bioavailability of HM and its subsequent incorporation into the food chain. Here, we evaluated HM bioaccumulation, biomass, morphological characters, chlorophyll content, and genotoxic damage in the herbaceous Crotalaria pumila to assess its potential for phytostabilization of HM in mine tailings. The study was carried out for 100 days on plants developed under greenhouse conditions under two treatments (tailing substrate and 75% tailing/25% coconut fiber biochar substrate); every 25 days, 12 plants were selected per treatment. C. pumila registered the following bioaccumulation patterns: Pb > Zn > Cu > Cd in root and in leaf tissues. Furthermore, the results showed that individuals that grew on mine tailing substrate bioaccumulated many times more metals (Zn: 2.1, Cu: 1.8, Cd: 5.0, Pb: 3.0) and showed higher genetic damage levels (1.5 times higher) compared to individuals grown on mine tailing substrate with biochar. In contrast, individuals grown on mine tailing substrate with biochar documented higher chlorophyll a and b content (1.1 times more, for both), as well as higher biomass (1.5 times more). Therefore, adding coconut fiber biochar to mine tailing has a positive effect on the establishment and development of C. pumila individuals with the potential to phytoextract and phytostabilize HM from polluted soils. Our results suggest that the binomial hyperaccumulator plant in combination with this particular biochar is an excellent system to phytostabilize soils contaminated with HM.

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This study focuses on the development of new amino-functionalized magnetic Fe2O3/SiO2 nanocomposites with varying silicate shell ratios (1:0.5, 1:1, and 1:2) for the efficient elimination of Hg2+ ions found in solutions. The Fe2O3/SiO2-NH2 adsorbents were characterized for their structural, surface, and magnetic properties using various techniques, including Fourier transform infrared spectrum (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Braunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), zeta-potential, and particle size measurement. We investigated the adsorption circumstances, such as pH, dosage of the adsorbent, and duration of adsorption. The pH value that yielded the best results was determined to be 5.0. The Fe2O3/SiO2-NH2 adsorbent with a silicate ratio of (1:2) exhibited the largest amount of adsorption capacity of 152.03 mg g-1. This can be attributed to its significantly large specific surface area of 100.1 m2 g-1, which surpasses that of other adsorbents. The adsorbent with amino functionalization demonstrated a strong affinity for Hg2+ ions due to the chemical interactions between the metal ions and the amino groups on the surface. The analysis of adsorption kinetics demonstrated that the adsorption outcomes adhere to the pseudo-second-order kinetic model. The study of adsorption isotherms revealed that the adsorption followed the Langmuir model, indicating that the adsorption of Hg2+ ions with the adsorbent occurred as a monomolecular layer adsorption process. Furthermore, the thermodynamic analyses revealed that the adsorption of Hg2+ ions using the adsorbent was characterized by a spontaneous and endothermic process. Additionally, the adsorbent has the ability to selectively extract mercury ions from a complex mixture of ions. The Fe2O3/SiO2-NH2 nanocomposite, which is loaded with metal, can be easily recovered from a water solution due to its magnetic properties. Moreover, it can be regenerated effortlessly through acid treatment. This study highlights the potential use of amino-functionalized Fe2O3/SiO2 magnetic nanoparticles as a highly efficient, reusable adsorbent for the removal of mercury ions from contaminated wastewater.

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The root of Salvia miltiorrhiza Bunge (SMB) has been widely used to treat cardiovascular diseases. However, the contents of secondary metabolites in the roots from different production areas are significantly different, and the impact of soil factors on this accumulation remains unclear. Therefore, this study aimed to elucidate the regularity of variation between the active components and soil factors through targeted metabolomics and chemical dosimetry. Soils were collected from five different cities (A, B, C, D, and E) and transplanted into the study area. The results showed that there were significant differences in the soil fertility characteristics and heavy metal pollution levels in different soils. Ten water- and twelve lipid-soluble metabolites were identified in SMBs grown in all soil types. SMBs from D cities exhibited the highest total tanshinone content (p < 0.05). The salvianolic acid B content in SMBs from E cities was the highest (p < 0.05). Interestingly, correlation analysis revealed a significant negative correlation between the accumulation of lipid-soluble and water-soluble metabolites. Double-matrix correlation analysis demonstrated that available potassium (AK) was significantly negatively correlated with salvianolic acid B (r = -0.80, p = 0.0004) and positively correlated with tanshinone IIA (r = 0.66, p = 0.008). Conversely, cadmium (Cd) and cuprum (Cu) were significantly positively and negatively correlated with salvianolic acid B (r = 0.96, p < 0.0001 and r = 0.72, p = 0.0024) and tanshinone IIA (r = 0.40, p = 0.14 and r = 0.73, p = 0.0018), respectively. Mantel's test indicated that AK (r > 0.52, p < 0.001), Cu (r > 0.60, p < 0.005), and Cd (r > 0.31, p < 0.05) were the primary drivers of the differences in the active components of SMBs. These findings provide a theoretical framework for modulating targeted metabolites of SMB through soil factors, with significant implications for the cultivation and quality control of medicinal plants.

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This study investigates heavy metal contamination in soils, irrigation water, and agricultural produce (fruits: Vitis vinifera (grape), Cucumis melo var. saccharimus (melon), and Citrullus vulgaris. Schrade (watermelon); vegetables: Lycopersicum esculentum L. (tomato), Cucurbita pepo (zucchini), Daucus carota (carrot), Lactuca sativa (lettuce), Convolvulus Batatas (potato), and Capsicum annuum L. (green pepper)) in the Boumerdes region of Algeria. The concentrations of seven heavy metals (cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn)) in soil and food samples were analyzed using atomic absorption spectrometry. Health risks associated with these metals were evaluated through the estimated daily intake (EDI), non-carcinogenic risks (using target hazard quotient (THQ), total target hazard quotient (TTHQ), and hazard index (HI)), and carcinogenic risks (cancer risk factor (CR)). Statistical analyses, including cluster analysis (CA) and Pearson correlation, were conducted to interpret the data. The results revealed the highest metal transfer as follows: Cd was most significantly transferred to tomatoes and watermelons; Cr to carrots; Cu to tomatoes; and Fe, Ni, Pb, and Zn to lettuce. Among fruits, the highest EDI values were for Zn (2.54·10-3 mg/day) and Cu (1.17·10-3 mg/day), with melons showing the highest Zn levels. For vegetables, the highest EDI values were for Fe (1.68·10-2 mg/day) and Zn (8.37·10-3 mg/day), with potatoes showing the highest Fe levels. Although all heavy metal concentrations were within the World Health Organization's permissible limits, the HI and TTHQ values indicated potential health risks, particularly from vegetable consumption. These findings suggest the need for ongoing monitoring to ensure food safety and mitigate health risks associated with heavy metal contamination.

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Soil in karst areas commonly exhibits characteristics of heavy metal enrichment. Accurate identification of soil heavy metal distribution, risks, and sources are crucial for preventing soil heavy metal pollution in karst areas. In this study, 2467 topsoil samples (0-20 cm) and 620 subsoil samples (150-200 cm) were collected using a grid-based sampling method in Tianyang County. Statistics, geo-statistics, correlation analysis, principal component analysis, and the absolute principal component-multiple linear regression model were utilized to analyze the content, spatial distribution and sources of heavy metals. The geo-accumulation index and the potential ecological risk index were employed to assess the ecological risks of heavy metals in the topsoil, with the subsoil content as baseline. The results showed that the study area's soil exhibited high heavy metal content, significantly exceeding Chinese background values. The content of heavy metals in the karst area's soil was notably higher than that in the non-karst area. The fitted semi-variogram models and the spatial distribution map revealed that the heavy metals' content was generally dominated by the geological background. As, Cr, Cu, Hg, Ni, Pb, and Zn displayed low levels of pollution in the topsoil and posed low ecological risk, with over 90 % of samples classified as unpolluted and low risk. Cd exhibited high levels of pollution and ecological risks, with 52.28 % of samples classified as polluted and 60.81 % classified as moderate to high risk. For Hg, despite only 6.94 % of samples showing polluted, the ecological risks were not negligible, with 40.65 % of samples in moderate to high risk. Natural source and anthropogenic source contribute to the heavy metals on average by 81.49 % and 18.51 %, respectively. This study provides a reference for the risk assessment of soil heavy metals, and its findings offer valuable scientific insights for the prevention of heavy metal pollution in the study area.

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Flooding, carrying sediments, inundates farmlands across the world due to extreme adverse weather conditions. The casualties and property damage associated with flooding are important direct impacts. However, there is currently insufficient understanding of the remobilization and distribution of heavy metals (HMs) caused by flooding. Few studies have specifically considered flooding as a pathway for HMs contamination of soil. Herein, a novel methodological framework for revealing the input pathways of HMs in agricultural soils in mining-intensive areas is proposed and applied. Flooding is considered one of the pathways for HMs inputs during source apportionment. The results demonstrated a high degree of overlap between the distribution characteristics of major HMs in agricultural soils and sediments. The degree of soil Cd pollution was significantly positively correlated with the inundation depth in the flooded area. It took 8.4-11.5 times of flood inundation or 98.5-119.9 years of accumulation of atmospheric deposition to reach HMs contamination levels in the soil of the study area. Flooding brought in most of the soil Cd, while atmospheric deposition was the primary input pathway for soil Pb and Zn. Our results identified the role of flood inundation on the input of HMs in mining-intensive areas. These results demonstrated the value of our framework for studying the impact of flooding on HMs in agricultural soils from the perspective of input pathways, providing new insights not only into identifying the sources of soil HMs but also into enhancing understanding of the impact of flooding on soil environments. With the potential increase in the frequency and intensity of flooding inundating farmlands in the future, it is essential to consider flooding as a pathway for HMs inputs in order to comprehensively assess their environmental impact.

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Culinary spices and herbs, renowned for their flavor, aroma, and medicinal properties, contain essential nutrients but also may pose health concerns due to heavy metal contamination. This systematic review, in accordance with PRISMA guidelines, investigates the global concentrations of heavy metals in culinary spices and herbs, and evaluates associated health risks. Fifty peer-reviewed studies from Scopus, PubMed, and Web of Science were examined and findings revealed variations in heavy metal content based on country of origin and spice type. In the MENA region, caraway and green cardamom from Bahrain had high levels of Pb (2.2 µg/g) and Cd (0.9 µg/g). Indian spices like cloves and Ajwain seeds exhibited high levels of iron (17.87±8 mg/kg) and calcium (1353±10 mg/kg). African and European spices showed regional disparities, with some exceeding permissible Pb and Cd limits. Non-carcinogenic human health risk assessments via oral exposure pathway conducted on reported Cd, Ni, and Cu concentrations throughout the reviewed global studies revealed no risks across all regions and for all spices and herbs under study except in Turkey for Cd levels found in chamomile with hazard quotients ranging between 1.26 and 1.47. On the other hand, carcinogenic risks varied based on reported Pb concentrations, ranging from 8.5 × 10-8 to a maximum of 4.96 × 10-3. These findings underscore the need for global vigilance in food safety practices and future research in countries with less stringent policies. Recommendations include improved agricultural practices, enhanced soil management, and stringent post-harvest procedures to mitigate contamination.

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Disposable e-cigarettes (vapes) are becoming increasingly popular but there are concerns about their impacts on human health, the environment and resource sustainability. A better understanding of these impacts and potential solutions requires characterisation and quantification of the materials and chemicals used in their construction. In the present study we dismantle nine types of popular, single-use vapes and analyse the components by X-ray fluorescence spectrometry and pyrolysis-gas chromatography mass spectrometry. The median dry mass of vapes was about 50 g, and the main material contribution was either plastic (up to about 80 %) or metal (up to about 85 %, and including the battery). Polycarbonate was the principal plastic used in the casing and nylon was always employed in the wick, but a range of other polymers were identified in other components used in wire insulation, sleeving, packaging, bundling and sealing. Various elements, as additives, residues or contaminants, were encountered in these parts that included As, Ba, Bi, Cr, Hg, Pb and Sb. Metal components were constructed of Al (often with Ti), stainless steel or Ni-based alloys (mainly in the coils), but other metals were often incorporated in alloys (e.g., Bi, Pb, W) or were present in trace quantities (including Co and Nb). Common metals in the Al-plastic-laminated Li-ion batteries were Cu, Co, Fe and Ni, but Au, Ba, Hg and Pb were also detected, while additional metals in the Cu-based printed circuit boards included Ag, Al, Ni, Sn, Ti and V, with traces of Ag, Bi, Mn, Nb and Pb present. The presence of toxic or potentially toxic metals in the vapes poses an environmental hazard through leaching after littering or landfilling, while metals within or in contact with the wick raise concerns about transfer to the e-liquid and exposure to the user. The overall material and chemical complexity of vapes presents challenges for safe disposal and component recycling, but the presence of critical elements, like Bi, Co, Nb, Sb, Sn, V and W, has additional implications for resource efficiency.

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There is a long-standing debate over the effectiveness of chemical extraction methods in assessing soil metal phytoavailability. This study addresses the limitations of widely-used chemical extraction methods and presents the water-extractable pool as a more reliable indicator based on wheat pot experiments using homogenized agricultural soil amended with lime materials, phosphate, and biochar. Over 120 days' pot experiments, Cd accumulation in whole wheat plants and tissues exhibited positive relationships with water-extractable Cd concentrations at heading and maturity stage (Spearman's rho: 0.521-0.851; P < 0.05), revealing that the water-extractable pool instead of other pools better indicates wheat metal accumulation. Water-extractable metal concentrations are effective in assessing phytoavailability of metals primarily in ionic forms in soil solution (e.g, Zn, Cd), but less reliable for metals strongly complexed with dissolved organic matter (DOM) or sensitive to redox conditions. It demonstrated that water-extractable metal concentrations and chemical forms are key factors, fundamentally determined by metal properties and impacted by environmental factors. This study clarifies a more direct link between chemical extraction and plant metal uptake mechanisms. Given the extensive application of chemical extraction methods over several decades, this study will help advance soil metal risk assessment and remediation practices.

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