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Ambient PM2.5 and their toxic components were measured in six ecologically different districts of India. Cadmium (Cd), arsenic (As), chromium (Cr), copper (Cu), zinc (Zn), molybdenum (Mo), and lead (Pb) were present in most of the PM2.5 samples analysed. A new heavy metal exposure index (HEI) was formulated based on weighted geometric mean approach using substance toxicity points given by Agency for Toxic Substance and Disease Registry (ATSDR). The proposed HEI differentiates toxic PM2.5 and helps screen unhealthy air pollution regions, and can thus assist in forming adequate public health policy. [ABSTRACT FROM AUTHOR]

With the excavation of landfill sites, the disposal and reduction of organic-rich soils with high proportions of heavy metals have become urgent issues. This study focuses on the pollution characteristics and ecological risks associated with heavy metals in the humus soil of a municipal solid waste (MSW) landfill. The results indicate that the concentrations of heavy metals in the humus soil followed the sequence of Cu > Zn > Cr > Pb > Ni > As > Cd > Hg, and Cu and Cd exhibited the highest exceedance multiples. Except for Cr, the concentrations of the heavy metals in the humus soil were higher than those in combustible components, with a strong Hg correlation. Heavy metal forms indicate varying degrees of mobility and stability; Cr, As, Hg, and Pb were stable, while Ni, Cd, Cu, and Zn showed higher mobility. The results of the principal component analysis reveal that heavy metals primarily originate from industrial and agricultural waste. Finally, the geoaccumulation index of the metals indicated that Cu, Zn, Cd, and Pb exhibited severe contamination. Most importantly, Cd posed the greatest environmental risk as it has the highest effective content, bioavailability, and mobility. This study provides a scientific foundation for mitigating heavy metal pollution in the humus soil of landfill sites. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the potential of replacing fly ash (FA) with bauxite tailing (BT) slurry for geopolymer synthesis and investigate the long-term leaching behaviour of BT slurry/FA geopolymers (BFGs) for heavy metal immobilisation. The mechanical properties and heavy metal immobilisation efficiency of BFGs were tested, and numerical simulations were conducted to assess their environmental impact as a backfill material. The results showed that the incorporation of 5 Wt.% BT increased the early compressive strength of the geopolymer without any additional treatment. A small quantity of Cu2+ improved the mechanical strength, while excess heavy metals harmed the geopolymer. Heavy metal immobilisation efficiency decreased with increased heavy metal addition and exceeded 99.9% for Pb2+ and Cu2+ when simulating acid rain leachate. The modified Elovich equation described the leaching kinetics of Cu2+ well, and the leaching rate decreased with time. Numerical analysis indicated that Cu2+ leaching from landfill leachate occurred in three phases, with an initial increase followed by a gradual decrease, stabilisation, and diffusion into the surrounding soil layer. This study provides insight into the material's long-term stability and environmental performance, offering a scientific basis for relevant engineering applications. Highlights: Direct utilisation of unprocessed tailing slurry to synthesise geopolymer. The leaching pattern of Pb2+ and Cu2+ under acidic conditions was explored. The modified Elovich equation effectively describes the leaching kinetics of Cu2+. The environmental impact of bauxite tailings slurry-based geopolymers was evaluated. [ABSTRACT FROM AUTHOR]

In recent years, heavy metals derived from several anthropogenic sources have both direct and indirect detrimental effects on the health of the environment and living organisms. Whole-cell bioreporters (WCBs) that can be used to monitor the levels of heavy metals in drinking and natural spring waters are important. In this study, whole-cell arsenic bacterial bioreporters were immobilized using polycaprolactone (PCL) electrospun fibers as the support material. The aim is to determine the properties of this immobilized bioreporter system by evaluating its performance in arsenic detection. Within the scope of the study, different growth media and fiber immobilization times were tested to determine the parameters affecting the fluorescent signals emitted by the immobilized bioreporter system in the presence of two dominant forms of arsenic, namely arsenite (As(III)) and arsenate (As(V)). In addition, the sensitivity, selectivity, response time, and shelf-life of the developed bioreporter system were evaluated. As far as the literature is concerned, this is the first study to investigate the potential of using PCL-electrospun fiber-immobilized fluorescent bacterial bioreporter for arsenic detection. This study will open new avenues in environmental arsenic monitoring. [ABSTRACT FROM AUTHOR]

With the increasing shortage of land resources and the aggravation of soil pollution in mining areas, the remediation of soil in abandoned mining areas has gradually attracted people's attention. The remediation of heavy metal contaminated soil in mining areas is the key to reduce the harm of heavy metals to the environment and human health. In this study, municipal sludge and phytoremediation technology were combined to investigate the migration and transformation of heavy metals at the soil-plant interface in improved mining areas through indoor pot experiments. The results showed that heavy metals in non-rhizosphere soil entered the rhizosphere environment with the growth of plants, leading to the increase of heavy metal content in rhizosphere soil. The cumulative amounts of Cu, Zn, Pb and Cd were 1299.32, 832.10, 347.89 and 71.34 mg/kg, respectively. The content of oxidized Cu and Zn decreased with increasing planting days, while the oxidized Pb and Cd showed an increasing trend. Under acidic conditions, H+ is easy to compete with heavy metal ions for exchangeable positions in the clay mineral layer, so that the reducible heavy metals are easy to be converted into exchangeable states. In this paper, the effects of various factors on the distribution of heavy metals were discussed by adjusting soil pH, adding humic acid and root exudates, so as to analyse the migration and transformation mechanism of heavy metals at the soil-plant interface, and provide a reliable theoretical basis for soil remediation in mining areas. [ABSTRACT FROM AUTHOR]

The content of heavy metal Cu in soil is an important indicator for assessing soil quality. However, soil hyperspectral data contain a large amount of redundant data, which can affect the effectiveness of spectral modelling. To address this problem, a combined method based on Whale Optimization Algorithm and Successive Projection Algorithm (WOA-SPA) is proposed to select the characteristic bands. And a prediction model of soil heavy metal Cu content was constructed using the partial least squares method. The experimental results show that: (1) The prediction accuracy of soil Cu content using the WOA-PLSR model was higher than that of the SPA-PLSR model, with RPD increased by 0.229, the R2 increased by 0.07, and RMSE decreased by 0.354. (2) Running the WOA and WOA-SPA combination algorithms 30 times respectively to prove the stability of the algorithms, the prediction accuracy of the model constructed based on the WOA-SPA combination algorithm is better than that of the model constructed based on the WOA algorithm as a whole. (3) Compared with the WOA or SPA algorithm alone, the prediction model constructed based on the WOA-SPA algorithm has a better prediction performance, with RPD of 2.259, R2 of 0.804, and RMSE of 2.396 for the prediction set. (4) Comparing the spatial distribution maps of the measured and predicted values, it can be observed that the spatial distribution between the predicted Cu content values based on the combined WOA-SPA algorithm and the measured Cu content values are basically consistent. This study indicates that the WOA-SPA-PLSR model has good stability and prediction accuracy for the prediction of Cu content in soil, which is of great practical significance for the rapid and accurate estimation of heavy metal Cu content in soil. HIGHLIGHTS: A novel dimensionality reduction method based on WOA-SPA was proposed. The WOA-SPA-PLSR model was constructed, which can accurately and quantitatively predict the content of heavy metal Cu in soil. The characteristic band selected by the WOA-SPA combination algorithm accounts for 2.79% of the full band, effectively reducing the dimensionality of soil hyperspectral data. Comparing the spatial distribution maps of measuredsoil Cu content and predicted soil Cu content,it can be found that the spatialdistribution of thetwois basically consistent. This shows that the WOA-SPA-PLSR model can effectively predict the spatialdistribution of soil Cu content in this area. [ABSTRACT FROM AUTHOR]

A long-term sustainable tungsten cathode-solution anode glow discharge (SAGD) source for atomic emission spectrometry was developed for the determination of heavy metal elements. The tungsten cathode of this source was cooled by a compact refrigeration semiconductor, which is simple in design and able to operate at atmospheric pressure for long periods. When the equipment operates at its optimal conditions (75 mA discharge current, 2.0 mm discharge gap, 3.8 mL min−1 flow rate, and solution pH value of 2.0), the detection limits of Ag (338.24 nm), Cd (228.80 nm), Hg (253.66 nm), Pb (368.28 nm), Tl (337.52 nm), and Zn (213.79 nm) were explored, and the values were 0.030, 1.7, 7.2, 17, 0.24, and 25 μg L−1, respectively. The interference of coexisting ions in water, such as K+, Ca2+, Na+, Mg2+, and Li+, on the analytical performance of the solution anode glow discharge-atomic emission spectrometry (SAGD-AES) for Cd, Hg, Pb, and Zn were investigated. The results showed that coexisting metal ions' interferences are insignificant. The SAGD-AES system was successfully applied for analyzing water samples from the Yangtze River and Baixi River, and its accuracy and practicality were verified by comparison with inductively coupled plasma-optical emission spectrometry (ICP-OES) results. [ABSTRACT FROM AUTHOR]

In present work, the genotoxicity of Hg2+, Ag+, Cr6+, Ni2+, Pb2+, Co2+, Mn2+, Zn2+, and Cr3+ was investigated via a quantitative toxicogenomics assay, to understand the toxic mechanism of heavy metals with greater depth. Under the experimental conditions, Hg2+, Ag+, and Cr6+ showed a more serious toxic impact on the expression of functional genes (eg., oxyR, katG, grxA, osmE, emrE, dinG) than Ni2+, Pb2+, Co2+, Mn2+, Zn2+, and Cr3+, while the protein, oxidative, and membrane stress response pathways were more sensitive to the toxicity of Hg2+, Ag+, and Cr6+ than the DNA and general stress response pathways. Compared with the other kinds of heavy metals, Ni2+, Pb2+, Co2+, and Mn2+ altered the expression of functional genes (uvrY, recX, mutY, and sbmC) related to the DNA stress response pathways more seriously, while Zn2+ and Cr3+ changed the expression of the functional genes (yfjG, ydgL, ssrA, and osmC) associated with the general stress response pathway more significantly. Meanwhile, the toxicity of Ni2+, Pb2+, Co2+, and Mn2+ was slightly higher than that of Zn2+ and Cr3+ in terms of the total value of transcriptional effect level Index (TELI) by detecting the promoter activities of different functional genes. In addition, to survive the toxicity of heavy metals, the expression of multidrug efflux genes (ydgL, cyoA, emrA, and emrE) and toxicity-resistant genes (Ion, dnaJ, clpB, mutY, dnaK, rpoD, sbmC) mainly functioned. [ABSTRACT FROM AUTHOR]

Global concern about the accumulation of heavy metal(loid)s (HMs) in agricultural soils and its subsequent effects on human health has increased. In particular, arsenic is a metalloid with known toxic and carcinogenic properties. This study was conducted with the aim of investigating arsenic contamination in agricultural soils of Hashtroud County, while assessing the levels of some heavy metals and the associated ecological and health risks due to possible exposure to these contaminants. The average concentrations of zinc (Zn), lead (Pb), nickel (Ni), copper (Cu), chromium (Cr), arsenic (As), cobalt (Co), and cadmium (Cd) (respectively, 72, 42, 41, 40, 24, 16, 13, and 0.6 (mg/kg)) did not exceed the national guideline value except for As. Arsenic was the element most enriched in the study area (enrichment factor (EF): 3.3). In general, the soil samples showed moderate ecological risk (RI = 174.17). The non-carcinogenic risks of HMs were acceptable, while the carcinogenic risk value (LCR) for As exceeded the threshold of 1 × 10−4 at 10% of the samples. Source attribution of HMs using the positive matrix factorization (PMF) model showed that Zn and Pb were mainly due to vehicle emissions. Agricultural activities and atmospheric deposition were the predominant sources of Cu and Zn; As and Cd were from natural sources; and Ni, Cr, and Co were from mixed sources of pedogenic factors and agricultural activities. To conclude, in study area, addressing arsenic as a main concern is crucial due to its ecological and health risks. The agro-geogenic source with a contribution rate of 64.87%, was identified as the primary origin of the elements. Further research is needed to investigate the bioaccumulation and bioavailability of HMs in the soil-crop system. [ABSTRACT FROM AUTHOR]

AbstractIn China, increasing breeding waste has caused environmental problems. This study explored the possibility of using breeding waste compost (BWC) instead of chemical fertilizer in vegetable cultivation. The experiment included no fertilizer (CK), 100% chemical fertilizer (CF), 10, 20, and 30% substitution of cow dung compost (CDC), goose dung compost (GDC), and duck dung compost (DDC) with chemical fertilizer (C01, C02, C03, G01, G02, G03, D01, D02, D03). The results showed that BWC, particularly GDC, promoted lettuce growth and development. Compared to CK, the leaf fresh and dry weight of G03 were the highest, increasing significantly by 6.60 and 7.29 times, and the root fresh and dry weight of G02 were the highest, increasing significantly by 12.72 and 6.00 times. Different BWC improved soluble sugar, soluble protein, and Vitamin C to varying degrees, and the nitrate contents of some BWC treatments were lower than that of CK and CF. Conversely, CF had the highest nitrate accumulation and limited effects on certain growth and quality parameters. The mineral elements in lettuce were also affected by the type and dosage of fertilizers. The total nitrogen of CF, total phosphorus of G03, total potassium of G02, Ca and Mg of D01, Fe of CF, and Zn of G02 were at the peak. The rapid increase of biomass in GDC treatments led to reductions in Ca and Fe. Applying fertilizers would affect heavy metals in lettuce to unequal degrees, but all were within the food safety scope. The principal component analysis revealed the comprehensive effect of GDC treatments was recommended. [ABSTRACT FROM AUTHOR]

This study analyses surficial sediments for heavy metal contamination in three different zones: Western India, Ganga Plains, and Central India. To estimate the geochemical environment of the surficial soil, five heavy metals, namely Co, Cu, Ni, Zn, and Pb were examined. Enrichment factor (EF) indicated the highest contamination for Co which showed deficient to minimal contamination in 11 samples, moderate contamination in 11 samples, significant contamination in 16 samples and very significant contamination in 1 amongst the 39 samples from various locations in all three zones depicted. The geo-accumulation index suggests that the variability in Co observed was −1.5 to 2.68 indicating augmentation of the Co concentrations in the study areas with respect to background values. Among 39 of the total locations sampled, 20 of them fall in the category of no pollution with respect to Pollution Load Index (PLI), while 18 fall under the category of moderate pollution and one location falls under the category of heavy pollution. Although all the indices suggested that the zones have not been subjected to extreme levels of pollution yet, appropriate measures may be taken to contain further anthropogenic contamination of these soils to preserve the surficial soils and their ecology. [ABSTRACT FROM AUTHOR]

AbstractIntroductionMethodsResultsDiscussionConclusionsKratom is commonly used by consumers, and the elemental impurity exposure that consumers would have at different kratom ingestion doses has been determined.This assessment used original data from independent third-party laboratory testing of kratom products to identify the percentage of products that exceeded permissible daily exposure limits for lead (5 µg/day), nickel (200 µg/day), arsenic (15 µg/day), and cadmium (5 µg/day), the interim reference level for lead in adults (12.5 µg/day), and the tolerable upper intake level for manganese (11 mg/day) and nickel (1 mg/day). We assessed all products regardless of type and then evaluated non-extract products, extract products, and a soda preparation separately for elemental impurities.Three assessments of elemental impurities in kratom products have been published, totaling 68 products. Assessing all products and assuming a 3 g daily dose of kratom, 7.4% would exceed the permissible daily exposure limits for lead, 0% for nickel, 3.1% for arsenic, and 0% for cadmium. At a kratom dose of 25 g daily, 70.6% would exceed the permissible daily exposure limits for lead, 20.6% for nickel, 9.4% for arsenic, and 0% for cadmium. The interim reference level for lead would be exceeded by 1.5% of products at a kratom daily dose of 3 g and 33.8% of products at 25 g. The tolerable upper intake level for manganese would be exceeded by 12.5% of products at a kratom daily dose of 3 g and 41.7% of products at 25 g. Non-extract products generally contain greater concentrations of elemental impurities than extract products or the soda preparation.Apart from their concentrations in a gram of product, assessing the amount of exposure to elemental impurities at different kratom ingestion doses is also important. Elemental impurities exceeding regulatory permissible concentrations for many products, especially with greater daily kratom ingestion doses, may impact human health.Some kratom products contain excessive concentrations of elemental impurities of toxicological concern, such as lead and arsenic. Non-extract products (powders, capsules, tablets) generally contain greater concentrations of elemental impurities than extract products or the soda preparation. Daily use of these products can result in exposures exceeding regulatory thresholds and adverse health effects. [ABSTRACT FROM AUTHOR]

Understanding the interactions of carbon and metal pollutants in anthropogenically impacted rivers is a prerequisite for determining the relative fates of these stressors. Here, through two sets of studies, we report carbon–metal pollutant interactions choosing the CO2 emission and sediment microbial extracellular enzyme activities as major determinants. The study, conducted along a 520-km main river and along a point source trajectory, showed a TOC-dependent but metal pollution-constrained CO2 emission. We found significant relationships (p < 0.05–0.001) between CO2 emission flux and its determinants: TOC, Cmic, FDAase and β-D-glucosidase. In the point source trajectory, CO2 emission flux was closely synchronous to these determinants. These relationships, however, were significantly constrained at the sites such as Knuj, Jjmu and Rjht where the concentrations of total heavy metal (∑THM) in the sediment exceed 347.44 µg g−1 indicating that the heavy metal pollution counteracted the C processing and consequently the CO2 emission flux. The study suggests that the excessive load of metal pollutants will eventually interrupt the C-cycling in the Ganga River inviting caution in C budgeting and C transport to coastal ocean. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTThe combined microbial-plant remediation has increasingly been used to remediate heavy metal-contaminated soil. Some microorganisms could enhance phytoremediation efficiency by solubilizing heavy metal and improve plant growth by producing phytohormones in the heavy metal contaminated soils. In the present study, a strong cesium (Cs)-tolerant fungal strain Paecilomyces lilacinus was identified from soil microorganisms contaminated with Cs, and the enrichment conditions for Cs were optimized. Furthermore, the effects of the A10 fermentation solution on the growth of Indian mustard (Brassica juncea L.) seedlings were investigated. The results indicated that the optimal combination of factors consisted of a culture temperature of 28 °C, pH7.0, initial concentration of Cs at 5.91 g·L−1. The maximum enrichment of Cs in the A10 was up to 75.36 mg·g−1 DW. In addition, the enrichment of Cs in Indian mustard was significantly enhanced by the application of the A10 fermentation solution, and the growth of Indian mustard was promoted under Cs stress. The present study has expanded the repertoire of microbial resources available for facilitating the Cs contaminated soil, thereby enhancing its applicability in the phytoremediation strategies.Recently, cesium (Cs) pollution has become a global environmental problem. Although much attention has been paid to combined microbe-plant remediation, there is still a lack of microbial strains with efficient Cs adsorption capacity to assist phytoremediation. The present study identified a new Cs accumulation fungus that effectively enhances the growth of Brassica juncea L. under Cs stress. In a word, the findings of this study have expanded the repertoire of microbial resources available for facilitating the Cs contaminated soil, thereby enhancing its applicability in the phytoremediation strategies. [ABSTRACT FROM AUTHOR]

A tomato cultivar ('Izmir F1') grafted onto six commercially available rootstocks ('Arnold', 'Dohkko', 'Emperador', 'He-man', 'Kaiser', and 'Suzuka') together with self-grafted plants of the tomato cultivar (Izmir/Izmir) were included in a pot experiment. Growth, root morphology and nutrient uptake parameters were evaluated under different salinity conditions (0 and 50 mM NaCl). Grafting increases root length, specific root length, and root length ratio, which enhances the capabilities of hetero-grafted plants to exploit a larger volume of soil or otherwise increase root density under root restriction conditions. Since the root traits and nutrient concentrations in hetero-grafted variants were less impacted by a change in the salinity level, the use of specific rootstocks ('Arnold,' 'Dohkko,' 'Kaiser') could contribute to a steadier growth and yield of tomato plants under fluctuating salinity levels in the irrigation water. The hetero-grafted tomato plants (Dohkko/Izmir, Suzuka/Izmir) demonstrated higher Na sequestration/compartmentalization capabilities than the self-grafted (Izmir/Izmir) plants which helps to maintain a more appropriate K+/Na+ ratio. By exhibiting lower translocation indexes of some heavy metals (Al, Ni, Zn, and Cd), appropriate rootstock/scion combinations might be a useful tool for reducing the risk of their accumulation in edible plant organs. [ABSTRACT FROM AUTHOR]

Rapid detection of potentially toxic heavy metals like Hg(II) has attracted great attention in the last few decades due to the importance to maintain a safe and sustainable environment for human beings. Coordination chemistry and concepts therein, play an important role in the detection of Hg(II). Size, charge, and nature of the donor atom and the respective cation (metal ion), are crucial in selective interactions between the sensor and metal ions. The sensors designed for the purpose, coordinate to Hg(II) ion through various donor sites, coordination causes a change in the electron density in organic molecules and results in either visible color change or enhancing/quenching fluorescence intensity. Since Hg(II) is soft metal, with d10 electron system, so majority of the sensors have soft donor sites which prefer to coordinate with Hg(II). Oxygen is also present in some chelating ligands which is least preferred coordination site, due to its hard nature. There are several reports of replacing other ligating sites by sulfur for enhanced mercury sensing. In some cases, desulfurization is being detected as clear change in spectral behavior during the sensing process. Efforts are still in progress to design and introduce a sensor with utmost sensitivity and selectivity. In this review, we made an attempt to explain the coordination aspects of Hg(II) detectors, reasons for poor efficiency and possible suggestions to improve the selection criterion of various compounds. It will help researchers to know about important concepts in designing more sensitive and selective sensors for detection of Hg(II) in environmental and biological samples. [ABSTRACT FROM AUTHOR]

Heavy metals ions as metallic pollutants are a growing global issue due to their adverse effects on the aquatic ecosystem, and human health. Unfortunately, conventional detection methods such as atomic absorption spectrometry exhibit a relatively low limit of detection and hold numerous disadvantages, and therefore, the development of an efficient method for in-situ and real-time detection of heavy metal residues is of great importance. The aptamer-based sensors offer distinct advantages over antibodies and emerged as a robust sensing platform against various heavy metals due to their high sensitivity, ease of production, simple operations, excellent specificity, better stability, low immunogenicity, and cost-effectiveness. The nucleic acid aptamers in conjugation with nanomaterials can bind to the metal ions with good specificity/selectivity and can be used for on-site monitoring of metal ion residues. This review aimed to provide background information about nanomaterials-based aptasensor, recent advancements in aptamer conjunction on nanomaterials surface, the role of nanomaterials in improving signal transduction, recent progress of nanomaterials-based aptasening procedures (from 2010 to 2022), and future perspectives toward the practical applications of nanomaterials-based aptasensors against hazardous metal ions for food safety and environmental monitoring. [ABSTRACT FROM AUTHOR]

In this study, surface dust samples were collected within the second ring road of Shenyang City under different land-use types, and the concentration and chemical speciation of metals in different particle sizes under different land-use types were analyzed. Dust samples were separated into four particle size fractions (＜50, 50–100, 100–500, 500–2000 μm), and particles in the range of 100–500 µm were the highest representing one-third of the dust mass. The results revealed that metals were detected in order Zn > Cr > Pb > Cu > Ni > As > Cd in different particle sizes of dust under different land-use types. The relative contribution of individual particle-size fractions for seven metals was different, but the results showed preferential partitioning to small particle-size fractions. The relative contribution of metals in individual particle-size fractions and chemical speciation were significantly affected by the type of land use. Metals concentrated on the smaller particles in the traffic area, and the particles (<50 µm) contained the highest percentage of metals but Cr. The residual fractions (F5) of Ni, Cr, As and Cu overall represented the predominant portion in different particle size of fractions under different land-use types, Zn and Pb were mostly bound to the Fe–Mn oxides-bound fraction (F3), and the exchangeable fraction (F1) accounted for a relatively large proportion of Cd. The results of the risk assessment code (RAC) of Cd indicated that the risk of Zn was medium, and it was high for Cd in the dust of Shenyang City. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the extent of the risk of lead (Pb) and cadmium (Cd) in the soil and wheat plants grown around the Zanjan cement factory in Northwest Iran and to assess the accuracy of soil regulatory standards in reflecting the potential risk of these pollutants. A total of 73 surface (0–20 cm) soil samples and 31 wheat plant samples were collected and analyzed for their Pb and Cd contents. Statistical analyses revealed that the soil Pb and Cd concentrations varied from 1.2 to 240.0 milligram per kilogram (mg kg−1) and below the detection limit to 27.5 mg kg−1, respectively. Additionally, the wheat grain content of these metallic pollutants ranged from below the detection limit to 3.5 and 1.6 mg kg−1, respectively, indicating that certain wheat samples were polluted with Pb, Cd, or both. Spatial analyses highlighted the significant role of the cement factory in spreading substantial amounts of HMs into the soil. By comparing the soil Pb and Cd total concentrations to their respective national regulatory standards, it was observed that 26.3% and 37.2% of the study area, respectively, were classified as polluted. Integrating the interpolated maps of soil Pb and Cd concentrations and identifying sites in which at least one pollutant exceeded its regulatory standard showed that a greater proportion of the area (42.3%) should be considered polluted. Finally, after accounting for sites in which either the soil was polluted and/or wheat grain content of Pb or Cd exceeded the threshold value of 0.2 mg kg−1, 67.4% of the area was classified as polluted. The findings suggest that thematic maps prepared for individual pollutants are inadequate for pinpointing the potential risk of soil pollution with HMs. Therefore, it is crucial to consider both the soil and plant aspects when assessing the risk of HM pollution in agricultural lands. [ABSTRACT FROM AUTHOR]

Most of Africa's illegal mining operations are conducted in rural areas, but along the Red Sea coast, they primarily occur in the Eastern Desert, where they are regarded as the major source of revenue. Soil samples were collected and examined at an illegal gold mining site in the far south of Egypt's Eastern Desert to determine the toxicity levels of eight heavy metals for pollution load index (PLI), Igeo, and health (Au, Ag, As, Hg, Ni, Cr, Zn, and Pb). The methodology used in this study was categorized into fieldwork with restricted rules within the visit, soil samples collected from the field, chemical analyses for heavy metals, and statistical analyses by applying six equations to define the environmental status of the study area. It was found that the PLI increases contamination as an environmental risk grade, Igeo, reaches grade 6, which is highly contaminated, and the average hazard index (HI) for the individual elements is high (>0.01). The health risk assessment results for Ni and Cr showed that oral intake was the main mode of exposure to heavy metals in the tailings of illegal mines. In addition, the average levels of As, Hg, Cr, Ni, Pb, and Zn were higher than the equivalent background levels for soils. Thus, adult cancer risk (CR) exceeds the permissible level of 10−4. The illicit mining activities in the Eastern Desert also resulted in heavy metal contamination with substantial noncarcinogenic hazards for As and Zn, necessitating urgent remediation. [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]

Quarries are regarded as crucial cornerstones of national economic development in Palestine. But they also have detrimental effects on the ecosystem and biological resources. Determination of the amount of heavy metals (chromium, cadmium, and lead) in quarries stumps is the main objective of the current research study. To accomplish this, 20 quarry stump samples were collected from four distinct regions of the Hebron Governorate in Palestine, using the quadrat method, and they were afterward calorimetrically assessed using a UV-visible spectrophotometer and pollution indices. The results reveal that the stumps possess Cr and Pb concentration below the international declared levels (1–1000 mg/l and 15–40 mg/l, respectively), while the Cd is above the declared level (0.2 mg/kg). The Cr and Pb content ranges from 0.128 to 0.611 mg/L and 0.125 to 0.779 mg/L, respectively. On contrary, the Cd contents varies from 0.362 to 8.572 mg/L in Hebron governorate. This level of Cd content, somehow, locate above their declared level by the international standards. In addition, the heavy metals content seems to be site-specific in the selected regions in Hebron governorate. The risk of cadmium is due to its high concentration, while the risk of Pb is because of its high toxicity. Moreover, the four regions are considered as uncontaminated and are clean based on PI Nemerow for Cr and Pb, but not for Cd. In conclusion, working on quarries in Hebron governorate is still safe from the levels of heavy metals point of view. However, more control and restriction must be implanted in order to mitigate its environmental and health consequences. Moreover, more research is needed to assess the occurrence of other heavy metals and their consequences on biological life and environmental issues. [ABSTRACT FROM AUTHOR]

This study was conducted in five randomly selected small-scale mining communities in the Amansie West District of Ashanti Region, Ghana to assess the impacts of small-scale mining activities on heavy metal presence in three different land use types (mined site, farmland and forest area). Using a random sampling design, a total of 60 soil samples were collected from 0–20 cm depth and analyzed for soil heavy metals: arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg) and copper (Cu) using Two-way ANOVA. Heavy metal concentrations for As (5.571 mg/kg), Cd (0.002 mg/kg), Cu (1.158 mg/kg), Pb (0.076 mg/kg) in the communities did not exceed the FAO/WHO permissible limits with the exception of Hg concentrations for the respective communities (0.68 mg/kg, 1.07 mg/kg, 1.26 mg/kg, 1.28 mg/kg, 17.03 mg/kg) whose levels were 2.3 to 56.8 times higher than FAO/WHO permissible limits (0.3 mg/kg). The distribution of heavy metals in the soil was not uniform across the different land use types in the mining landscape. Differences in heavy metal concentrations were significant (p <.05) at the community, land use and their interaction (community*land use) levels with the exception of As concentration at the land use level (p >.05). The study concludes that soils of the major land use types in the study area (mined sites, farmlands and forest area) are all contaminated by Hg accumulation. Therefore, effective rehabilitation of mined sites in mining-plagued-communities should include measures for removing mercury from the soil. [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]

Microplastics (MPs) are ubiquitous in terrestrial and marine environments. This research work studied the occurrence, distribution of MPs and heavy metals associated with these MPs in soils of different land- use types viz. residential, commercial, and industrial areas. We identified 15 types of MP polymers, of which polypropylene (15.51%), polyethylene (12.28%), polyamide (9.57%) were dominant. MPs abundance ranged from 8.54 × 104 to 8.51 × 105 particles/kg of soil. Average abundance of MPs in the three fractions viz. < 1 mm, 1–2 mm, and 2–5 mm were 1.85 × 105, 1.31 × 105, and 697.5 particles/kg of soil, respectively. Among the three land use types, MPs abundance in < 1 mm and 1–2 mm soil fractions were significantly higher in residential areas than that in commercial and industrial areas, i.e. <1 mm: 3.4 × 105, 1.26 × 104 and 9.0 × 104, and 1–2 mm: 2.35 × 105, 8.36 × 104, and 7.50 × 104 particles/kg, respectively, for residential, commercial and industrial areas respectively. The average concentration of Cr, Fe, Mn, Cd, Co, Ni, Cu and Pb in soils were 31.79, 11047.29, 423.92, 0.05, 11.86, 17.53, 125.95 and 28.29 mg/kg, respectively, whereas that in MPs were 6.27, 2181.64, 277.36, 0.24, 6.43, 8.29, 47.05 and 9.24 mg/kg, respectively. Concentration of Cd sorbed on MPs was higher than those found in soils. Also, Pb and Cd in MPs were positively correlated to MPs abundance, indicating MPs can be vectors of heavy metals in soils. The synergistic effect of MPs and heavy metals might put soil organisms at risk. [ABSTRACT FROM AUTHOR]

Long-term application of organic and inorganic fertilizers increases the possibility of contamination of greenhouse soils with heavy metals. This study investigated heavy metals (Cd, Co, Cu, and Zn) adsorption-desorption under mono and competitive systems in 10 soils from agricultural and greenhouse soils in western Iran. In most of the studied soils, the values of the Freundlich distribution coefficient (Kf) of Cu were higher than other heavy metals, indicating that Cu is maintained by the soils stronger than Cd, Co, and Zn. Based on the average Kf, the selectivity sequence of heavy metals in agricultural and greenhouse soils was ordered as Cu > Zn > Cd > Co in both mono and competitive systems. In general, greenhouse soils had lower Kf for heavy metals compared with agricultural soils, indicating the vulnerability of greenhouse soils to heavy metals leaching. In desorption experiments, the percentage of heavy metal desorption increased as the concentration of added heavy metals increased in both systems (except Cu in the mono-heavy metal system). The findings revealed that continuous vegetable production and the application of organic and inorganic fertilizers in these greenhouse soils may cause changes in soil properties and heavy metal mobility, posing hazards to human health and groundwater quality. [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]

To understand the source, distribution and degree of pollution of heavy metals in the soil around a plateau municipal solid waste incineration plant, a municipal solid waste incineration plant in Lhasa was taken as the research object in this study. The soil surrounding the facility was sampled, and the contents of heavy metals, including Cu, Pb, Zn, Cr, Ni, Cd, As, and Hg, in the soil were analyzed. Then, heavy metal pollution and risk assessments were conducted using the geoaccumulation index method, Nemerow index method, and potential ecological risk index method. Additionally, correlation and principal component analysis were used to determine the correlation between heavy metals in the soil and their sources of pollution. The results showed that based on the Nemerow comprehensive pollution index, the soil surrounding the incineration plant generally had a low level of pollution. Through the analysis of individual potential ecological risk indices, it was found that only the heavy metal Cd presented moderate potential risks, while the other seven heavy metals had mild potential risks. The average value of the total potential risk coefficient was 107.31, which was less than 150, indicating that there was a slight potential risk associated with the soil around the incineration plant. There was significant correlation between six heavy metals, namely, Cu, Pb, Zn, Cr, Ni, and Cd, in the soil around the incineration plant. Their pollution sources were similar, and their levels tended to be affected by the incineration plant. However, there was no significant correlation between the heavy metals As and Hg and the other six heavy metals. These two heavy metals had independent sources of pollution but were also influenced by human activities. [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]

In India, ∼30% of total land is degraded due to pollution, salinization, and nutrient loss. Change in soil-quality at urban waste-dumping site prior and after cow-dung amendment was compared with control agriculture soil. The soil at waste-dumping site had elevated pH, EC, temperature and lowered OC and NPK concentrations when compared to control. Polymetallic pollution of Cr, Cd, Pb, and Ni beyond permissible limits was obtained. Cow-dung amendment restored soil physicochemical properties at the waste-dumping site, with increasing soil moisture, CEC and OC; however, a slight change in soil bulk-density and heavy-metal concentration post-amendment was noted. The seven natural colonizers present at the waste-dumping site accumulated more metals in roots than shoots. Datura innoxia had maximum bioaccumulation of Cr, Calotropis procera of Cd and Ni and Parthenium hysterophorus of Pb in roots. All these plants had Bioacccumulation factor (BAfroot )>1 and translocation factor (Tf) <1 for Cd and serve as its phytostabilizer except Calotropis procera which had BAfroot >1 and Tf >1 and is identified as a phytoextractor for Cd. Cow-dung amendment alone appeared to be insufficient and additionally the revegetation of natural colonizers is recommended for effective reduction in heavy metal load and improving overall soil health at wasteland. Such eco-restoration may also minimize risks to biodiversity in India. Novelty statement: The novelty of the work lies in revegetation of natural colonizers at polluted wasteland to reduce heavy metal load and improve overall soil health. Calotropis procera, Datura innoxia, Parthenium hysterophorus, and S. nigrum showed maximum bioaccumulation of Cr, Cd, Pb, and Ni. The work confirms C. procera as non-edible, fast growing natural colonizer as potential phytoextractor for Cd and taken into consideration to effectively restore heavy metals polluted wasteland. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) have different biological mechanisms to alleviate stressful conditions in heavy metals (HMs) polluted soil. These mechanisms were widely assessed under controlled/greenhouse conditions, but scarcely studied at pilot or territory scale. The aim of this study was to evaluate the response of two Rhizophagus intraradices strains isolated from soils with different histories of pollution, in association with Senecio bonariensis plants, growing in an engineering vegetal depuration module filled with artificially HMs polluted substrate. Plants inoculated with GC3 strain uptook low amounts of HMs and translocated them to shoot biomass. Heavy metals (Mg, Zn, Mn, Cr, Cu and Ni) and macronutrients (Ca, K, S and P) were accumulated in roots of S. bonariensis when inoculated with GB8 strain, limiting their translocation to the shoot. Uninoculated plants showed high translocation of all studied elements to shoot tissues. Concluding, tested R. intraradices strains have exhibited different phytoprotection mechanisms under extremely toxic concentrations of HMs. Moreover, the development of the assay at such a high Technological Readiness Level represents a novel contribution in this field of study. [ABSTRACT FROM AUTHOR]

The efficacy of SA foliar use on Pb and Ni-induced stress tolerance and phytoremediation potential by Portulaca oleraceae L. were assayed as a factorial trial based on a completely randomized design with four repetitions. The factors included; SA foliar application (0 and 100 µM) and HMs application of Pb [0, 150, and 225 mg kg−1 soil Lead (II) nitrate] and Ni [0, 220, and 330 mg kg−1 soil Nickel (II) nitrate]. Plant height, stem diameter, shoot and root fresh and dry weight, photosynthetic pigments, total soluble proteins, palmitic acid, stearic acid, arachidic acid, and some macro- and micro-elements contents were reduced facing the HMs stress, but SA foliar application ameliorated these traits. HMs stress increased malondialdehyde content, total antioxidant activity, total flavonoids, phenolics, and linolenic acid content, while SA foliar application declined the mentioned parameters. Moreover, shoot and root Pb and Ni content enhanced in the purslane plants supplemented by SA under the HMs stress. The results propose SA foliar application as a reliable methodology to recover purslane growth characters and fatty acid profiles in the soil contaminated with the HMs. The idea is that SA would be potentially effective in alleviating HMs contamination while keeping reasonable phytoremediation potential. NOVELTY STATEMENT: There is no information available in previous literature about the impact of Pb and Ni on the phytochemical profile of oil in purslane. Therefore, in this report, we evaluated the purslane plant's growth and physiological responses and its seed oil's components in response to SA foliar application under conditions of Pb and Ni over-availability. Additionally, we examined the role of SA treatment in improving phytoremediation of Pb and Ni. [ABSTRACT FROM AUTHOR]

In this study, the results showed that the soil radioactivity concentrations of 232Th and 40K were higher than the reference values given by UNSCEAR, but still within radiologically safe limits. Heavy metal concentrations were within allowable limit according to Vietnamese standards. Radioactivity and metal concentrations in the topsoil did not increase compared with the 30 cm depth after a period of operation. After one year of operation, the gamma dose rates of the area around the plant showed no difference according to the one-way ANOVA test (p = 0.944). The results indicated that after a period of operation, the coal-fired thermal power plant did not shown any significant impact of radioactivity and metals from the fly ash on the surrounding environment. [ABSTRACT FROM AUTHOR]

This study examined the heavy metal content in dust storm samples from Erbil, Iraq, along with four other locations. Using ICP-MS, Cd, Ni, Cr, Hg, Pb, Zn, Mn, Cu, Co, Fe and As were determined. The health risks due to exposure to these metals through ingestion, inhalation and dermal contact were assessed for both adults and children. Non-carcinogenic risks were evaluated using the hazard quotient (HQ) and hazard index (HI). Children faced a cumulative risk with HQ > 0.2 for As and Cr and HI > 1. The carcinogenic risk was measured using the carcinogenic risk factor (CRF), which fell below 10–6, indicating low cancer risk. However, children had a higher cancer risk (10−4 to 10−6) for As. The pollution indices revealed varying pollution levels from unpolluted to moderately polluted in the studied areas. Overall, this study highlights potential health risks associated with heavy metal exposure during dust storms, particularly for children, and emphasises the importance of addressing these concerns to safeguard public health. [ABSTRACT FROM AUTHOR]

The current study focused on quantifying hazardous heavy metals (As, Cd, Cr, Pb, Ni, and Zn) in soil-rice systems near the Buriganga River in Bangladesh to assess their impact on human health and the environment. The mean concentrations of As, Cd, Cr, Ni, and Zn in soil exceeded FAO/WHO acceptable limits, and the metal pollution index (MPI) indicated that all soil samples collected from the rice fields were severely polluted (MPI˃30) than water and rice grain samples. According to the sum of pollution index (SPI) by studied metals, rice grains collected from Kamrangirchor (29.36), Dhakauddan (28.75), and Bosila (18.08) were severely polluted. Mean Bio-concentration factors (BCFs) and Transfer factors (TFgrain/soil) in rice grains were in the following order: Cd (6.034) > Zn (1.752) > Pb (0.697) ˃ Ni (0.666) > Cr (0.135) > As (0.037), and Cd (1.150) > Zn (0.421) > Ni (0.112) ˃ Pb (0.072) > Cr (0.015) > As (0.034) respectively indicating higher accumulation of Cd in rice grain than others toxic heavy metal. The potential ecological risk index (RI) showed that except for water in Kamrangirchar and Keraniganj rice fields, all other rice fields soil and water samples did not pose severe ecological pollution (RI˂110) by different toxic heavy metals. Health risk assessment showed that rice grains are unsafe for human consumption as the carcinogenic health risk (CHR˃10-3) and non-carcinogenic health risk (HI ˃1) quotients seem more than the safe level in all samples collected from rice fields surrounding the Buriganga River. Findings show that heavy metal concentrations are high in rice fields near the Buriganga River, endangering the environment and consumer health. [ABSTRACT FROM AUTHOR]

The rapidly growing electroplating industry has led to the discharge of large amounts of wastewater containing heavy metals and organic acids. Innovative techniques are required for the efficient and effective treatment of such effluents. The present work explored electroplating wastewater treatment through new TiO2-NTs/GO/SnO2 electrodes by electro-oxidation (EO) in batch and once-through continuous system. A new electrode with excellent oxidation ability was successfully fabricated by introducing a SnO2 outer layer through a simple anodization method. Moreover, a response surface methodology (RSM)-Box-Behnken design (BBD) model was used to optimize the responses. The effects of operating conditions, i.e. pH (3–9), current (0.1–0.9 A), and time (30–180 min), on the efficiency of the process were investigated. With optimum conditions, 97.1% Cu, 95.7% Zn, 91.2% COD degradation, and 7.32 kWh/m3 energy consumption were achieved. A once-through continuous setup working at a flow rate of 5–20 mL/min was performed under optimal conditions. The electrodes remained durable even after 50 cycles. The contribution of several reactive species to the EO was examined in the presence of scavengers. Moreover, according to a toxicity study, EO can detoxify electroplating effluents. Hence, this EO process, which is low-cost and highly efficient, can be applied to the treatment of electroplating wastewater. [ABSTRACT FROM AUTHOR]

The adsorption of weighty metal particles from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Heavy metal ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, design ability, and stability have been proposed. In this review, a carbon-based adsorbent, named M-NC, and graphene oxide were created for the particular evacuation of weighty metal particles. To increase the potential for Heavy Metals (HM) immobilization, sulfide-modified biochar was created via a process called synchronous carbon layer epitome. A hypothetical physicochemical and thermodynamic examination of the adsorption of weighty metals Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was done with factual material science fundaments. The biochar with large surface areas is utilized to eliminate weighty metal particles, quite possibly the most significant heavy metal pollutants, from aqueous solutions. The limit of the adsorbent for eliminating weighty metal ions was concentrated on utilizing Langmuir adsorption isotherm under ultrasound-helped conditions. The Mesoporous Silica Nanoparticles (MNCs) can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous measurable physical science adsorption typically was utilized to describe and analyze the experimental heavy metal removal isotherms at 30°C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The experimental results were investigated in terms of Langmuir and pseudo-2nd-order kinetic equations, Freundlich and isotherm models. The outcome of pH, initial heavy metal ion concentration, contact time, and adsorbent dosage regarding the adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the hydrogel was examined. This study contributes to the advancement of information in the ground of environmentally friendly heavy metal removal techniques, specifically focusing on the usage of biomass-based adsorbents. These findings have the potential to address the need for effective solutions in water purification and environmental cleanup efforts. [ABSTRACT FROM AUTHOR]

Copper tailings are a common byproduct of copper production, containing high levels of heavy metals which are released into the environment. Conventional methods have historically prioritized copper recovery, and often overlooking the leaching of other valuable elements. However, the rising demand for nonferrous metals necessitates understanding their leaching behavior from copper tailings. This study examined the atmospheric leaching of Cu, Fe, Pb, Zn, and CuO from a polymetallic tailing ore. Leaching recoveries of 63.5% for Cu, 97.5% for CuO, 1% for Fe, and 100% for Zn were achieved under the optimum conditions of 0.5 M sulfuric acid concentration, 25% solids percentage, 65°C, stirring speed of 100rpm, particle size of 75 µm within 30 minutes. Results indicated that the dissolution of oxide minerals such as CuO and ZnO was significant; however, copper sulfides need oxidant to be dissolved. In this condition, iron oxides and silicates were partially reacted by sulfuric acid, and Pb-bearing minerals formed lead sulfate. The presence of iron and lead-bearing minerals in the leaching residue was confirmed by XRF, XRD, and SEM analyses, and was in agreement with the information displayed in the Eh-pH diagrams. [ABSTRACT FROM AUTHOR]

Prolonged use of the chromate [Cr(VI)]-contaminated water originates severe health problems for the public. Thus, the societal urgency is a reusable and cost-effective material for efficient scavenging of Cr(VI) from contaminated industrial wastewater. Aiming this, we had targeted to prepare some cheap and effective materials for scavenging Cr(VI) from the contaminated water. Herein, we report the preparation of hydrous cerium-copper oxide (HCCO) with some tailored compositions and employed toward the abstraction of chromate from water solution. The HCCO (Ce: Cu = 1:4, mole/mole) has shown the highest Cr(VI) scavenging capacity. Experimentally, highest Cr(VI) abstraction efficiency is recorded at pH ~ 3.0 (508.853 mg. g−1 at 303 K). Kinetically, the Cr(VI) scavenging reaction with HCCO surfaces agrees better with the pseudo second-order model (R2 = 0.987) equation and the equilibrium Cr(VI) distribution data explain the Freundlich isotherm model (R2 = 0.998) equation, which anticipates the multi-layered adsorption on heterogeneous sites of the adsorbent. A negative value of the Gibbs free energy change indicates that the Cr(VI) adsorption over HCCO surfaces is spontaneous. The positive enthalpy change indicates the endothermic nature of the said reaction. HIGHLIGHTS: One-pot synthesis of hydrous Ce(IV)-Cu(II) oxide (HCCO) and characterizations. Systematic Cr(VI) scavenging from modeled ground water with HCCO. Best fit pseudo-second-order kinetic model, implying the chemisorption mechanism. Very high amount of Cr(VI) scavenging at ambient condition reported to be 508.85 mg.g−1. Coulombic interaction between HCCO and Cr(VI) is responsible for scavenging Cr(VI). [ABSTRACT FROM AUTHOR]

In this study, the Geo-accumulation index (Igeo), Human Health Risk Assessment (HRA), and Ecological Risk Index (ERI) were utilized to examine the risks associated with the soils at the DaeyangYeongseong mine. Brassica juncea and Raphanus sativus were employed in the ecological toxicity test. In all soil samples, the mean Igeo value of arsenic measured 3.15, and cadmium measured 6.63, indicating a very high level of heavy metal contamination. The carcinogenic risk of cadmium and arsenic for adults was 4.30×10−3 and 1.43×10−5, respectively. For children, these values were 3.92 × 10−2 and 1.33 ×10−4, exceeding the acceptable level (1×10−6). In all soils, cadmium showed extremely high ecological risk levels, and arsenic had extremely high risk levels in 34.8% of the total area. This was also confirmed in toxicity assessments using plants. Therefore, arsenic and cadmium were found to be the main causes of soil contamination and ecological risk. [ABSTRACT FROM AUTHOR]

Potentially toxic metals in water threaten humans, animals, and the environment. The potential of Indian willow (Salix tetrasperma) leaves to biosorb copper and lead from water was examined. Utilising scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FTIR) spectrum analysis, the properties of Salix tetrasperma biomass (STB) was investigated. The maximum removal percentage (92.8% for copper and 89.9% for lead) was achieved at pH 5.0, a biosorbent dosage of 3.0 g/L at 25°C, and a 10 mg/L initial concentration of copper and lead. The determination of the point zero charge (pHzpc = 5.0) indicated the prevalence of a negative charge on the surface of the biosorbents. The kinetic equation utilised in the pseudo-second-order model effectively. Langmuir isotherm better described experimented data than the Freundlich model. The Dubinin-Radushkevich isotherm provided a good fit for the study's equilibrium data. STB recorded an adsorption capacity, Qmax, of 43.99 mg/g for copper (II) and 39.66 mg/g for lead (II) ions at an optimum pH of 5. Thermodynamically, the biosorption of both ions on STB was spontaneous, endothermic, and feasible. The selected modified STB was found to be suitable for adsorbing copper (II) and lead (II) metal ions. [ABSTRACT FROM AUTHOR]

The study investigates biometric indicators of assimilation and reproductive organs of coniferous and deciduous trees in urban environments: leaf area, inflorescence flower count, stipule length of Tilia cordata Mill. and needle length and weight of Scots pine (Pinus sylvestris L.). Samples of wood, needles, leaves and soil from the planting sites were analysed for 17 chemical elements, including Hazard Class I elements (Arsenic, Lead, Cadmium, Mercury, Selenium) and Hazard Class II elements (Chromium, Cobalt, Nickel, Copper, Molybdenum, Antimony). Tree plantations decreased airborne dust by 30–40% compared to open areas. Concentrations of PM2.5 and PM10 particles showed a direct correlation with busy roads (p < 0.05). In instances of environmental degradation, healthy trees exhibited in needle an increase in biomass and a reduction in weight and length. Consequently, forestry measurements and the impact of the urban environment require specific and individual monitoring of trees, rather than a general assessment of plantations. [ABSTRACT FROM AUTHOR]

The present study assessed the heavy metal pollution in sediment samples collected from the Noyyal River basin (river and lake sediments) during the monsoon and summer seasons. The geo-accumulation index (Igeo) categorizes metals as extremely polluted during monsoon and heavily contaminated to extremely contaminated during summer. The enrichment factor (EF) of metals Mn during monsoon and Cd during summer indicates extremely severe enrichment (EF > 50) and Mo exhibited very high contamination (CF > 6) throughout the basin during monsoon. The average risk index of heavy metal in the basin followed the order Cd (164.15) > Ni (14.82) > Co (4.84) > Cr (2.55) > Cu (1.89) > Zn (1.38) > Mn (0.40) during monsoon and Cd (153.07) > Ni (7.96) > Cu (5.13) > Co (4.63) > Cr (1.89) > Zn (1.21) > Mn (0.3) during summer showing that the PERI of each element was minimal except for Cd. Adverse health-related effects are confirmed by the cumulative total hazard index (THI) for children with HQ ingestion and HI values >1 in all sample locations over both seasons. Principal component and cluster analysis show metals accumulate in sediments mainly through industrial wastewater discharge and also experience significant natural source weathering through rainfall runoff. This research emphasizes the need for enhanced wastewater treatment facilities in metropolitan areas situated along the Noyyal River to potentially reduce the release of heavy metals from both domestic and industrial sources. [ABSTRACT FROM AUTHOR]

AbstractLivestock wastewater (LWW) has a complex characteristic of high organic matter content, metals, nutrients, and pharmaceutical compounds. Advanced oxidation processes (AOP) are a potential option for treating this wastewater. This study evaluated real LWW and the performance of UV/H2O2 and UV/peroxymonosulfate (UV/PMS) for its treatment. The experiments were conducted in a UV photoreactor (16 mW/m2, λ = 254 nm). The oxidant agents (Ox) tested were H2O2 and PMS, each at low, medium, and high TOC/Ox molar ratios. A pretreatment based on chemical precipitation was implemented. Annually, the LWW showed total organic carbon (TOC) values of 859 ± 13.37 mg/L, 168.85 ± 1.62 mg/L of total Kjeldahl nitrogen (TKN), and toxicity of 96% v/v. In the dry season, albendazole (ABZ) (95.3 ± 35.16 mg/L), Cu (4.3 ± 0.23 mg/L), Fe (3.8 ± 0.38 mg/L), and suspended solids (SS) (1015 ± 586.9 mg/L) were identified, so pretreatment was implemented. The UV/PMS process with the lowest molar ratio [TOC/Ox 1:0.75] removed significantly lower TOC concentrations (p < 0.05), but toxicity decreased entirely. The study of mineralization and toxicity provided insight into the changes in LWW during treatment with AOP. Furthermore, it contributed to establishing the technical basis for implementing efficient treatment processes. [ABSTRACT FROM AUTHOR]

The aim of the current case study is to sequentially assess the heavy metals (HMs) cadmium (Cd), iron (Fe), lead (Pb) and zinc (Zn) in five products (raw juice, bagasse, mud-cake, refined sugar and molasses) along with the effluents of the selected sugar industry (SSI) Sindh, Pakistan. Estimations of daily intake and possible toxic risk of HMs by the consumption of sugar of SSI to end-user (families of SSI workers) of age group of 2.0–5.0, 6.0–15.0, 16.0–30.0 and 31.0–50.0 years were conducted. The high contents of HMs were observed in molasses followed by mud-cake and bagasse (raw waste). The raw juice of sugarcane and refined/white sugar showed the lowest levels of these HMs. The low levels of HMs in effluents of SSI might be to their separation at different stages of sugar processing and refining into the mud-cake, bagasse and molasses. The calculated daily intake of Fe and Zn from refined/white sugar to various study groups was found to be adequate based on the recommended levels by Food and Nutrition Board (FNB). The estimated weekly intake (WI) for Cd and Pb by the consumption of SSI sugar was significantly lower (2–5 times) than the provisional acceptable WI of Cd and Pb by WHO from foodstuff. The potential toxic risk study of Cd and Pb revealed that the studied subjects were not at potential toxic risk by the consumption of SSI sugar. [ABSTRACT FROM AUTHOR]

Radionuclides and heavy metals/metalloids content in soils and shore sediments of Al-Negila area (Matrouh, Egypt) were determined to assess the associated environmental risks. A total of 46 soil and shore sediment samples were collected and analysed for natural and man-made radionuclides (238U series, 232Th series, 40K and 137Cs) and heavy metals/metalloids (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Si, Sr, Zn, and Hg). Within the study area, the soil and shore sediments are mainly calcareous with sandy, sandy clay and silty clay sized textures. The radionuclides and metals/metalloids concentrations in the soil were higher than those in the shore sediments, meanwhile, they are within the safe world average values. The estimated average (±SD) activity concentrations of 226Ra, 228Ra, 40K and 137Cs were 20.3 ± 5.3, 17.8 ± 6.3, 353.1 ± 129.8, and 2.7 ± 2.7 Bq/kg, respectively. The activity concentration of 137Cs is characterised by the greatest variability characterising the fallout deposited radionuclides. The estimated average values of Raeq (72.9 ± 23.7 Bq/kg), air absorbed gamma dose rate (34.9 ± 11.4 nGy/h), annual effective dose (42.8 ± 14.0 µSv/y), and external hazard index (0.2 ± 0.1) are lower than the international averages reported by UNSCEAR 2008. The average concentrations (mg/kg) of heavy metals/metalloids in soil samples decrease in the following order: Mn (129.8) > Sr (95.0) > Si (28.8) > Ba (25.7) > Zn (25.1) > Cr (17.6) > B (10.0) > Ni (3.9) > Cu (3.3) > Co (0.5) > Cd (0.007) > Hg (7.0 µg/kg). According to the classes of pollution load and contamination degree indices, soils and shore sediments of Al-Negila area are generally uncontaminated. However, a few sampling sites were considered moderately contaminated with B, Cd, and Sr. The radionuclides and heavy metal/metalloid contents in the soil and shore sediments of the area should be observed and assessed regularly, especially for 137Cs. [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]

The Sefidrud River, which flows into the Caspian Sea after traversing the northern Iranian province of Guilan, is the principal river in the southern Caspian Sea. Its water is utilized for drinking, agriculture, and aquaculture, while industrial and agricultural wastewater is discharged into this valuable body of water. This study aimed to measure the concentration of two heavy metals, nickel and lead, and organochlorine toxins in the water and sediment of this river. Water samples were taken from the Sefidrud River at three stations in four seasons to measure the concentration of the above-mentioned two heavy metals organochlorine toxins as well as some physiochemical parameters of the water. Results showed that the annual mean water temperature, calcium, magnesium, electrical conductivity (EC), T.D.S, pH, and dissolved oxygen in water samples were 16.35°C, 77 mg/l, 28.41 mg/l, 1245.41 mS/m, 782.7, 8.01, and 7.91 mg/l. The mean annual concentration of nickel and lead was also 0.008 ± 0.001 and 0.001 ± 0 mg/l in water and 29.75 ± 1.19 and 313.4 ± 17.13 mg/l in sediments. The results also showed that the mean annual concentration of Pertilachlor was 0.40 ± 0.046 mg/l in water and 2.91 ± 0.476 mg/l in sediments, and the mean annual concentration of Saturn was 2.81 ± 0.47 mg/l in water and 0.39 ± 0.47 mg/l in sediments. Since the sediments of the Sefidrud River contain relatively high concentrations of heavy metals such as lead and nickel as well as organochlorine toxins, the river should be regarded as polluted; therefore, the discharge of pollutants and wastewater into this river should be properly managed. [ABSTRACT FROM AUTHOR]

AbstractThe present work describes a greener method of preparation of Fe3O4 nanoparticles, which are then functionalized to Fe3O4@SiO2@SO3H, and employed in the one-pot three-component synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[3,2-c]chromene derivatives. These synthesized derivatives are an important class of heterocyclic scaffolds and exhibit significant potential as anti-coagulant, diuretic, spasmolytic, anticancer, and anti-anaphylactic agents. The prepared MNP-based catalysts were characterized using XRD, FE-SEM, VSM, TG-DTA, and Raman spectroscopy. The synthesis of derivatives involved the condensation reaction of enolizable compounds with aldehyde, dimedone, and ethyl cyanoacetate for tetrahydrobenzo[b]pyran, and the reaction of aromatic aldehyde, 4-hydroxycoumarin, and malononitrile for dihydropyrano[3,2-c]chromene synthesis. The reaction was optimized using different techniques such as stirring, ultrasonication, and microwave irradiation, with microwave irradiation method demonstrating faster product separation and high yield. The homogeneity of the isolated product was analyzed by FT-IR,1H-13C-NMR, and mass spectrometry. The advantages of this method include its simplicity, eco-friendliness, cost-effectiveness, and it also evades the use of toxic metals and solvents. The product is easily isolated through a simple workup process and recrystallization using ethanol yields pure product isolation. [ABSTRACT FROM AUTHOR]

The distribution and removal pathways of heavy metals within different sludge treatment wetlands (STWs) during different running periods in Northeast China have not been well studied. In this study, we examined three STWs, i.e. an STW with aeration tubes only (unit 1; U1), an STW with reeds and aeration tubes (unit 2; U2), and an STW with reeds only (unit 3; U3). The results showed that the levels of Cu as well as Zn accumulated faster within STW residual sludge, whereas the levels of Cd, Cr, Ni, and Pb accumulated more slowly and decreased slightly over time. The removal rates of heavy metals from the influent sludge by STWs ranged from 64.5% (Cr) to 92.2% (Zn). Reeds removed heavy metals from the STWs by direct absorption, and Zn was highly enriched in the reeds. The presence of reeds also promoted the spreading of heavy metals to the substrate layer and improved the removal of heavy metals in STWs. The mass of each heavy metal accumulated within the residual sludge of U2 and U3 was lower than that of U1, indicating that reeds could facilitate the removal of heavy metals. The STWs removed heavy metal mainly by substrate adsorption, and the mass percentage of heavy metals accumulated in the substrate ranged from 35.8 to 63.6%. [ABSTRACT FROM AUTHOR]