Search

Toxic metals and metalloids pollution is a major ecological and human health issue, yet classical detection methods are limited. Here we review surface-enhanced Raman spectroscopy-based sensors using nanomaterial-based substrates for metal detection, with emphasis on substrate composition, functionalization, and assembly; metal sensing strategies; and analytical performance. Substrates include nobel metals, semiconductors, and composites. Substrate assembly can be done in solution or on solid supports. Sensing strategies comprise direct sensing, reporter recognition, reporter migration, substrate aggregation, and substrate modification. In general, the physicochemical properties of the substrates determine sensor sensitivity through electromagnetic and chemical enhancements of Raman scattering, whereas substrate surface functionalization, or lack thereof, determines sensor selectivity and the sensing mechanism. The main elements analyzed are mercury, lead, copper, arsenic, and chromium. [ABSTRACT FROM AUTHOR]

Copyright of Österreichische Wasser- und Abfallwirtschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Immense industrial growth contributed to tremendous pollution of the environment from a variety of sources. Bioremediation of different toxicants, such as heavy metals and dyes, is greatly appreciated for its cost-effective and environmentally friendly approach. The bacterial strains isolated from textile dye-contaminated soil samples were used in the study for the removal of the toxic pollutants. The bacterial strains were molecularly identified as E. hormaechei subsp. steigerwaltii and Bacillus sp. B2022 using 16S rRNA sequencing. The preliminary batch study results of the bacterial co-cultures showed a maximum removal efficiency of 88.57 ± 0.005% on mixed dyes and 90.18 ± 0.005% on Cr (VI) respectively. The scale-up laboratory-sized batch reactor showed the results were the maximum removal percentage of 77.68 ± 0.005% with mixed dyes and 52.79 ± 0.005% on Cr (VI) observed for 6 days. The degraded metabolites analyzed by FT-IR revealed the presence of C-H, C = O, C-O, and C–Cl functional groups. The GC–MS study showed the presence of few metabolites such as decane, undecane, 2,4,6-trimethyl decane, butyl tetradecyl ester phthalic acid, and 2,6,10 trimethyl tetradecane. The integrated treatment approach of applying different techniques in a single platform is positively encouraged in the era of urbanization and industrialization. [ABSTRACT FROM AUTHOR]

In this study, Copper (II) adsorption from an aqueous solution with nanoparticles synthesized using organic waste was investigated. For this purpose, the extract obtained from Allium cepa (A. cepa) peel was used as a reducing agent, and zinc oxide nanoparticles (ZnO NPs) were synthesized by the green synthesis method. The synthesized ZnO NPs were obtained as composite adsorbents with halloysite (HNT), a type of clay. The adsorbents were characterized by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), X-ray diffractometer (XRD), dynamic light scattering spectrometry (DLS), N2 adsorption–desorption analysis and zero charge point (pHPZC) analysis. Parameters affecting the adsorption process such as pH, adsorbent dose, contact time, initial metal concentration, and temperature were investigated. According to the correlation coefficient, the data obtained with ZnO NPs were best summarized by the Langmuir isotherm with an adsorption capacity of 500 mg g−1. The kinetic description of the adsorption system was performed by pseudo-second-order kinetic and intraparticle diffusion kinetic models. Thermodynamic parameters were calculated and the adsorption process was found to be spontaneous and exothermic. [ABSTRACT FROM AUTHOR]

Cadmium (Cd), a significant environmental pollutant, is highly toxic to humans, animals, and plants. Its harmful effects are notable even at low concentrations, and it persists in biological systems for extended periods. Given its classification as a type I carcinogen, monitoring changes in the Cd concentration in the air is highly important. This study explored the variation in Cd concentrations in specific plant species and plant organs at different vehicular traffic densities to identify the most effective species and organs for the biomonitoring of Cd concentrations in the air. The Cd concentration changes in different organs of five plant species were analyzed at various vehicular traffic densities. The findings suggest that among the species examined, Nerium oleander is most suitable for use as a biomonitor for Cd, with unwashed organs being recommended for biomonitoring purposes. [ABSTRACT FROM AUTHOR]

Solid waste management is a burning issue that requires special attention and consideration in developing countries. In most cities and towns, it has become a public health concern due to uncontrolled dumping that has caused degradation of the natural environment. Therefore, the present study assessed the impact of dump yards on the surrounding environment by conducting physicochemical and biological analysis of groundwater and leachate samples and comparing it with control sites located at Silchar town of Assam, India. The result demonstrated that a large number of organic materials and inorganic salt leached to the surrounding environment by the decomposition of waste at open dumping site which significantly pollutes the groundwater sources of nearby areas. The sample site S5 recorded the highest value of WQI (100.78). Contamination of Total Coliform and E. Coli bacteria were recorded in the range of 96–2116 CFU/100 ml and 0–2466 CFU/100 ml respectively in sample sites. However, in control sites, coliform bacteria were found in the range of 8–43 CFU/100 ml and E. coli bacteria was found to be absent in all the control sites. The mean concentrations of Pb (8.94 mg L−1), Mn (19.12 mg L−1) and Ni (6.38 mg L−1) in the dump yards were found above the maximum permissible limit of EPA US, 1986; however, the concentrations of Cu (4.05 mg L−1) and Cd (0.45 mg L−1) were within the permissible limit. Hence, there is a need for proper scientific planning and management of waste disposal for the protection of our surrounding environment. [ABSTRACT FROM AUTHOR]

Heavy metal levels have steadily risen over the past century due to the presence of human activity and are hazardous to human health and the environment. Regarding the health of humans and the environment, palladium (Pd) is among the most hazardous and toxic heavy metals. It is listed as a priority contaminant by the Agency for Toxic Substances and Disease Registry (ATSDR). As a result, eliminating pollution and tracking changes in Pd contamination in the air are the top research priorities. This study will be conducted on trees grown in Düzce, the fifth dirtiest city on the European continent, to identify appropriate species that may be utilized for tracking and mitigating Pd pollution in the air. Samples from Cupressus arizonica, Pinus pinaster, Cedrus atlantica, Pseudotsuga menziesii, and Picea orientalis will all be analyzed as part of the study, and the variations in Pd content according to species, organ, and direction will be assessed. The goal is to ascertain which biomonitors are best suited for tracking and mitigating lead contamination in the atmosphere. The study consistently found Pd contents in woods with different directions that developed within the same period. However, when the species were compared, notable differences were detected between the Pd levels formed in different directions in the same period for each species and the wood formed in the same direction in other periods. This variation suggests that Pd transfer in wood is restricted in all tested species. Consequently, every species performs as a reliable biomonitor for tracking Pd contamination. [ABSTRACT FROM AUTHOR]

Considering both electrokinetic remediation and phytoremediation have limitations, an electrokinetic phytoremediation (EP) system was constructed to obtain efficient and environmentally friendly remediation results. This study indicates that the electric field can promote the absorption of Cd by ryegrass with little impact on soil physicochemical properties under the condition of rotary switching electrodes, and the accumulation of Cd in the aboveground and underground parts of ryegrass increased by 145.2% and 93.7%, respectively. The DC electric field combined with ryegrass under rotary switching electrode mode proved to be the optimal condition for the remediation of Cd contaminated soil with a remediation efficiency of 66.7%. Moreover, the rotary switching of the electrodes alleviated the suppression of the growth of ryegrass by the DC electric field. During the EP remediation process, the electric field promoted the transformation of the residue state of Cd to the other forms, which accelerated the desorption rate of Cd from the soil and facilitated the migration of Cd into plants. In conclusion, EP is a green and efficient remediation technology for heavy metal contaminated soil with good application prospects. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Geochemistry & Health is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There has been a significant rise in cancer-related mortality in the Ladakh region during the past 10 years. The most common type of case is gastrointestinal cancer, which has been linked in theory by medical research to lifestyle factors, high altitude conditions, and the prevalence of Helicobacter pylori bacteria brought on by poor hygiene. Nevertheless, the precise cause of the rise in cancer cases is still unknown. Concurrently, there has been a significant change in Ladakh's water use practices due to development, improved basic utilities, and related vocational shifts. The local population has become increasingly reliant on groundwater since it provides a year-round, continuous water supply for home and agricultural uses. In this study, we assessed heavy metal contamination in groundwaters and associated human health risks. The results indicate that 46–96% of the groundwater samples have heavy metal pollution with a health hazard index > 1, which means using these groundwaters for drinking, food preparation, and agriculture is likely to result in carcinogenic and non-carcinogenic health hazards. The main heavy metal contaminants found in the groundwater of the Leh district include Cr, As, Hg, and U. According to the health risk assessment, 46–76% of the groundwater samples contain unsafe levels of Cr and As. Prolonged exposure to these levels is likely to cause gastrointestinal cancer in the local population. Acute to chronic exposure to U and Hg concentrations present in some groundwater samples is likely to result in various non-carcinogenic health risks. [ABSTRACT FROM AUTHOR]

Heavy metals pose significant threats to human health, particularly children. This study aimed to assess heavy metal pollution in children's playgrounds using surface dust as an indicator and to ascertain the associated exposure levels and health risks. A total of one hundred twenty dust samples were collected from the surface of playground toys in areas surrounding the cement factory in Bursa, Türkiye, on precipitation-free days. The heavy metal content of the samples was analyzed using ICP-MS. The average total concentration of heavy metals ranged from 2401 to 6832 mg/kg across the sampling sites, with the highest values observed at PG4, PG3, PG2, and PG1, respectively. The most commonly detected heavy metals in the samples included Cr, Mn, Fe, Co, Cu, Zn, Pb, Cd, As, and Ni. Statistical analysis revealed significant positive correlations (p < 0.01) among Cr, Mn, Fe, Co, Cu, Pb, As, and Ni, with Cu and Pb also showing correlation (p < 0.05). PCA analysis identified three principal components explaining 79.905% of the total variance. The Hazard Quotient (HQ) and Hazard Index values for heavy metals were found to be below the safe threshold (HQ < 1). Quantitative techniques such as the geoaccumulation index and enrichment factor are used to determine pollution levels at the sampling sites. Overall, the results indicate that cement factories significantly contribute to heavy metal pollution, with observed values varying based on proximity to the emission source. [ABSTRACT FROM AUTHOR]

The efficacy of herbal supplements in mitigating heavy metals (HMs) toxicity was investigated using a widely grown fish, the Nile tilapia (Oreochromis niloticus). The experiment was conducted over two phases: during the stress phase, the experimental fishes were exposed to sub-lethal concentrations of HMs, including lead, cadmium, zinc, and copper for 15 days; following which during the feeding phase, herbal supplements were given for 70 days to ameliorate their effects. Seven groups were established: the control negative group (CON−ve), control positive group (CON+ve, without any treatment), and five groups with supplementation of 1% turmeric (TUR), cinnamon (CIN), ginger (GIN), garlic (GAR), and their mixture (MIX), respectively. A total of 315 fishes were distributed evenly in experimental tanks (15 fishes per tank, in triplicates). The results revealed that exposure to HMs led to significant (p < 0.05) alterations in all the tested parameters, i.e., liver damage and growth reduction. The herbal supplements, especially the MIX groups, ameliorated the harmful effects of HMs and restored fish growth, digestibility, carcass composition, and liver health. In conclusion, the study demonstrated that the herbal supplements were effective in reducing the HMs-linked toxicity in Nile tilapia. Future studies pertaining to the mechanisms facilitated by the various herbal bioactive substances-linked tolerance to HMs in fishes are warranted. [ABSTRACT FROM AUTHOR]

Non-conventional heavy metal oxide glasses have attracted great interest owing to their unique optical properties and their radiation shielding behavior. Non-conventional glasses of main chemical composition (100 − x) PbO–xBi2O3 where x = 35, 30, 25, 20, 15, 10, and 5 were prepared through the conventional melting and annealing approach. X-ray diffraction measurements denoted the amorphous nature of the prepared glasses. The optical absorption in the UV–visible range recorded strong UV-near visible absorption spectra that correlated to trivalent Bi3+ ions. The optical band gap Eopt, Urbach energy ∆E, and the refractive index were identified for the prepared glasses employing the cognizant theories. The variations in the optical parameters have been associated with the increasing Bi2O3 and the doses of γ- irradiation. The photoluminescent properties of the prepared non-conventional binary Bi2O3–PbO glasses were recorded in the visible range after UV excitation and the color coordinates are located and distributed in the hue violet degree. FT-IR spectroscopic measurements before and after gamma irradiation were applied to investigate the structural changes in the binary heavy metal PbO–Bi2O3 glasses. FTIR data specified that the glass network is composed of different structural building units from BiO3/BiO6 and PbO3/PbO4 depending on the addition ratio between PbO and Bi2O3. [ABSTRACT FROM AUTHOR]

Heavy metal concentrations, which have increased continuously in the environment this century due to anthropogenic factors, severely threaten human and environmental health. Antimony (Sb) is one of the most toxic and harmful heavy metals in terms of human and environmental health. Therefore, the priority research subjects are monitoring the alteration of Sb pollution in the airborne and reducing pollution. This study was conducted to conclude the proper species to monitor and drop airborne Sb contamination on trees grown in Düzce, the 5th most polluted European city. This study examined samples taken from Pseudotsuga menziesii, Cupressus arizonica, Pinus pinaster, Picea orientalis, and Cedrus atlantica, and the Sb concentration changes based on tree species, route, tissue, and age range in the last 40 years were evaluated. The study hypothesizes that Sb concentration varies depending on (1) tree species, (2) direction, (3) plant tissue, and (4) age range, all confirmed in this study. In conclusion, the maximum concentrations were achieved in the outer bark and east (5.45 µg g−1) and north directions (6.72 µg g−1), with high traffic density. In addition, the mining and industrial places (sources of metal pollution) are not close to the study area. Therefore, it was concluded that traffic pollution was the primary source of Sb pollution in the study area. The study revealed that C. arizonica is the most suitable species for monitoring and reducing the change in Sb pollution because the highest Sb concentration (4.47 µg g−1) in wood (the largest organ) was obtained in C. arizonica. [ABSTRACT FROM AUTHOR]

The coconut (Cocosnucifera) is renowned for its endocarp, commonly referred to as the coconut shell, which is believed to harbor a high concentration of silicon, potentially serving as a source for the production of silicon nanoparticles (SiO2NPs). This study demonstrated the synthesis of SiO2NPs derived from coconut shells and their application in the removal of metal contaminants, notably copper. SiO2NPs were synthesized with a recovery rate of 25.6%, yielding a white powder through the sol–gel method. Analysis via ultraviolet–visible (UV–Vis) spectroscopy revealed an absorbance peak maximum at 345 nm, indicative of strong surface plasmon resonance, thus confirming SiO2NPs formation. Morphological characterization conducted through field-emission scanning electron microscopy (FE-SEM) and field-emission transmission electron microscopy (FE-TEM) confirmed the smooth-faced nature of the SiO2NPs, presenting finely clumped particles with an average size of 62 nm. Furthermore, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) analyses exhibited distinct peaks corresponding to oxygen (O) and silicon (Si), confirming SiO2NPs formation. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the particles, with a 25% weight loss observed at 500 °C according to thermogravimetric analysis (TGA). Assessment of the adsorption capacity for heavy metals from water solutions by spiking various copper (II) sulfate concentrations indicated the highest adsorption rate at 0.05 M copper, diminishing with increased copper ion concentrations. Evaluations utilizing different SiO2NPs concentrations demonstrated optimal copper (Cu) removal efficiency at 0.2 g/mL SiO2NPs. [ABSTRACT FROM AUTHOR]

Heavy metals are extremely hazardous for human health due to their toxic effects. They are non-biodegradable in nature, thus remain in the environment and enter and accumulate in the human body through biomagnification; hence, there is a serious need of their remediation. Phytoremediation has emerged as a green, sustainable, and effective solution for heavy metal removal and many plant species could be employed for this purpose. Plants are able to sequester substantial quantity of heavy metals, in some cases thousands of ppm, due to their robust physiology enabling high metal tolerance and anatomy supporting metal ion accumulation. Identification and modification of potential target genes involved in heavy metal accumulation have led to improved phytoremediation capacity of plants at the molecular level. The introduction of foreign genes through genetic engineering approaches has further enhanced phytoremediation capacity manifolds. This review gives an insight towards improving the phytoremediation efficiency through a better understanding of molecular mechanisms involved, expression of different proteins, genetic engineering approaches for transgenic production, and genetic modifications. It also comprehends novel omics tools such as genomics, metabolomics, proteomics, transcriptomics, and genome editing technologies for improvement of phytoremediation ability of plants. [ABSTRACT FROM AUTHOR]

The increasing proximity of the Dudumbia dumpsite, an open dumpsite in Navrongo, Ghana, to human settlements necessitates an investigation of the soil quality to safeguard the environment from heavy metal toxicity. This study examined the impact of waste dumping activities on the physicochemical properties of the soil, as well as the level of heavy metal (Pb, Cd, Ni, Cr, As, Hg, Cu, Mn, and Zn) contamination and associated risks. Various contamination and risk assessment tools were used, including the geoaccumulation index (Igeo), pollution load index (PLI), potential ecological risk (Er), and potential ecological risk index (PERI). The study found significant improvements in notable soil attributes such as phosphorus (P), organic carbon (C), total nitrogen (N), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), and effective cation exchange capacity, with percentage increases ranging from 50.8 to 2078.3%. Igeo values ranged from 2.07 to 6.20, indicating contamination levels from moderate to extreme. The PLI and PERI values were 16.241 and 1810, respectively. The Er values for the heavy metals ranged from 36 to 607, indicating ecological risk levels from low to very high, with Cd and Hg posing very high risks. These results suggest that while the dumpsite soil shows improvements in some characteristics favourable for plant cultivation, waste dumping significantly contributes to heavy metal contamination. The soil at the dumpsite is deteriorated and poses significant health risks, particularly due to Cd and Hg. Therefore, remediation efforts should prioritise mitigating the risks posed by Cd and Hg. [ABSTRACT FROM AUTHOR]

Rice intake represents a significant pathway through which humans accumulate heavy metals. This study presents a comprehensive analysis of heavy metal and pesticide contamination in rice cultivars irrigated with industrial wastewater near Dhaka, Bangladesh, a region heavily influenced by industrial activities. This study employed a unique methodology that not only quantified the concentrations of heavy metals and pesticide residues in rice grains but also extended to evaluating the physicochemical properties of rice stems, husks, soil, and irrigation water. The findings revealed alarmingly high levels of heavy metals such as lead, cadmium, chromium, nickel, and mercury in the soil and irrigation water, with concentrations in some cases exceeding the World Health Organization safety thresholds by 2 to 15 times. Notably, the rice grains also exhibited significant contamination, including substantial amounts of diazinon and fenitrothion pesticides, exceeding the established safety limits. The study employed hazard quotients (HQs) and cancer risk (CR) assessments to evaluate the potential health risks associated with the consumption of contaminated rice. The results indicated HQ values were greater than 1 for rice grains across the sampled fields, suggesting a considerable non-carcinogenic health risk, particularly from lead exposure, which was found at levels twice the standard limit in all the sampling fields. Moreover, the CR values for As, Pb, Cd, Co, and Mn highlighted a significant carcinogenic risk in several instances. [ABSTRACT FROM AUTHOR]

Water pollution by heavy metals or iodine is a serious environmental issue that poses a threat to human health and ecosystems. Therefore, there is a need for developing efficient and low-cost methods for removing heavy metals and iodine from water sources. Activated Opuntia ficus-indica (AOFI) has been used for various purposes such as food, medicine, cosmetics, biofuel, and soil stabilization. The aim of this study was to investigate the feasibility of using AOFI as an adsorbent for removing heavy metals; e.g. Cr(III), Pb(II), and Cu(II) and iodine from water. The leaves of AOFI that were collected from Al-Baha city, KSA, were carbonized and characterized using FTIR spectroscopy and TGA analysis. Then uptake experiments were performed to evaluate the effects of various parameters such as pH, contact time, initial concentration, and temperature on the removal uptake by AOFI. Also the thermodynamic and kinetic parameters of the adsorption process had been calculated. The adsorption capacity of AOFI and OFI against iodine, Cr(III), Pb(II), and Cu(II) had been calculated. The results showed that; AOFI has adsorption capacity 1.14, 1.14, and 1.16 times higher than OFI, for Cr(III), Pb(II), and Cu(II), respectively, and 1.05 times higher than OFI, for iodine uptake. The findings indicated that AOFI exhibited remarkable efficacy in the metal ions uptake, achieving uptake efficiency up to 70%. Additionally, AOFI demonstrated notable efficiency in iodine uptake, reaching up to 60%. These results underscore the high uptake efficiency of AOFI for both metal ions and iodine, emphasizing its potential as an effective adsorbent for water treatment applications. This study is novel because it is the first to report the adsorption of heavy metals; such as Cr(III), Pb(II), and Cu(II) and iodine by AOFI. [ABSTRACT FROM AUTHOR]

This study explored a soil remediation method combining FeCl3 + hydrochloric acid washing with bentonite, kaolinite, and peat passivation to remove lead (Pb), arsenic (As), uranium (U), and thorium (Th). The treatment lowered soil acidity and effectively reduced the harmful forms of these metals, particularly making Pb less available. The best results for Pb and Th were with kaolinite passivation, while peat worked better for U and similarly effective for As. The soil's chemical properties slightly changed without affecting its structure or mineral content, as confirmed by FT-IR, SEM–EDS, and XRD analyses. This approach offers a balanced solution for contaminated soils, improving safety without damaging the environment. [ABSTRACT FROM AUTHOR]

Lake Tanganyika, the second deepest lake in Africa, has a unique ecosystem that provides rich fish proteins for populations along the lake basin. With socioeconomic development and rapid population growth, Lake Tanganyika is threatened by environmental pollution. In this study, the concentrations of heavy metals, including Cr, Ni, Cu, Zn, Cd, Pb, Fe, and Mn, in the surface sediments of the inflow rivers in northeastern quadrant of Lake Tanganyika were characterized. The geoaccumulation index (Igeo) and enrichment factor (EF) were employed for heavy metal assessment. The results showed that heavy metal concentrations in the surface sediments of the inflow rivers in northeastern quadrant of Lake Tanganyika exhibited significant spatial variations. The concentration of heavy metals was the highest near urban areas, followed by the estuarine wetland and forest grassland. This indicated that heavy metal content was closely related to human activities. The concentrations of Zn, Cd, and Pb were defined as unpolluted, and the concentrations of Pb, and Fe were only slightly enriched. Principal component analysis and cluster analysis demonstrated that the heavy metals Cr, Zn, Cd, and Pb may originate from a mixture of natural sources and anthropogenic inputs, including agricultural and industrial inputs. Ni, Fe, and Mn were principally from natural sources, and Cu primarily originated from anthropogenic inputs such as vanadium iron ore mining and iron and steel smelting. These results are important for understanding the nonpoint sources of heavy metal pollution in the Lake Tanganyika Basin. [ABSTRACT FROM AUTHOR]

Ash emission from volcanic eruptions affects the environment, society, and human health. This study shows the total concentration and lung bioaccessible fraction of eight potential toxic metal(loid)s in five Popocatépetl ashfall samples. Mineralogical phases and particle size distribution of the ashfall were analyzed by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) techniques, respectively. The bioaccessibility test of Gamble solution (GS) and Artificial Lysosomal Fluid (ALF) were conducted to simulate extracellular (pH 7) and intracellular (pH 4.5) conditions, respectively. The studied metal(loid)s showed the following total concentration (mg kg−1): 1.98 (As), 0.17 (Cd), 134.09 (Cr), 8.66 (Cu), 697.33 (Mn), 55.35 (Ni), 8.77 (Pb), and 104.10 (Zn). Geochemical indices suggested that some metal(loid)s are slightly enriched compared to the local soil background concentrations. Several mineralogical phases were identified in the collected ashfall deposits, such as plagioclase, pyroxene, and Fe–Ti oxide, among others. According to the risk assessment results, the non-carcinogenic risk related to ashfall exposure returns an HQ > 1 for children. In contrast, the estimation of carcinogenic risk was found to be within the tolerable limit. Metal(loid)s showed low bioaccessibility (< 30%) in GS and ALF, with the highest values found in ALF solution for As (12.18%) and Cu (7.57%). Despite their metal-bioaccessibility, our findings also showed that dominant ash particle size ranged between fine (< 2.5 μm) and extremely fine (< 1 μm), considered highly inhalable fractions. The results obtained in this work indicate that volcanic ashes are bioinsoluble and biodurable, and exhibit low bioaccessibility when in contact with lung human fluids. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) seriously harm soil environment and threaten crop quality and human health. The aim of the study was to investigate the characteristics, quantify the sources and assess the risks of HMs in soil of upper Bailang River Basin (UBRB). The results indicated that the soils in UBRB were at a non-polluted level and posed a low ecological risk to the environment as a whole. The main pollutants were Ni and Cr obtained by indices Pi and Igeo. Based on the consideration of toxicity, the fuzzy comprehensive evaluation model and Ei index revealed that Hg and Cd were dominating pollutants and ecological risk factors of soil in UBRB. The positive matrix factorization model ascertained five potential sources of soil HMs, namely, plastic processing, energy activities, parent material, transportation and agriculture mixed source and industrial manufacturing, with contribution rates of 17%, 7%, 15%, 29% and 32%, respectively. Natural source primarily determined the non-carcinogenic risk for all populations, accounting for about 43% of the total risk. Industrial manufacturing mainly determined the carcinogenic risk, accounting for about 45%. For adults, the risk was acceptable for most of the sample points. For children, potential non-carcinogenic risks were present in 13.19% of the sample sites, which were mainly located in the west, and unacceptable carcinogenic risks were present in 57.21% of the sample sites, which were mainly concentrated in the western and central parts. [ABSTRACT FROM AUTHOR]

Highly acidic citrus pomace (CP) is a byproduct of Pericarpium Citri Reticulatae production and causes significant environmental damage. In this study, a newly isolated acid-tolerant strain of Serratia sp. JS-043 was used to treat CP and evaluate the effect of reduced acid citrus pomace (RACP) in passivating heavy metals. The results showed that biological treatment could remove 97.56% of citric acid in CP, the organic matter in the soil increased by 202.60% and the catalase activity in the soil increased from 0 to 0.117 U g−1. Adding RACP into soil can increase the stabilization of Cu, Zn, As, Co, and Pb. Specifically, through the metabolism of strain JS-043, RACP was also involved in the stabilization of Zn and Pb, and Residual Fraction in the total pool of these metals increased by 10.73% and 10.54%, respectively. Finally, the genome sequence of Serratia sp. JS-043 was completed, and the genetic basis of its acid-resistant and acid-reducing characteristics was preliminarily revealed. JS-043 also contains many genes encoding proteins associated with heavy metal ion tolerance and transport. These findings suggest that JS-043 may be a high-potential strain to improve the quality of acidic organic wastes that can then be useful for soil bioremediation. [ABSTRACT FROM AUTHOR]

In this study, the impacts of LEDs on the phytoremediation of arsenic (As) and mercury (Hg) by Bacopa monnieri (L.) Wettst. were investigated, along with the examination of the biochemical characteristics of plants exposed to metal-induced toxicity. In vitro multiple and rapid plant propagations were successfully achieved by adding 1.0 mg/L 6-Benzyl amino purine (BAP) to the Murashige and Skoog (MS) basal salt and vitamin culture medium. For plant-based remediation experiments, different concentrations of As (0–1.0 mg/L) and Hg (0–0.2 mg/L) were added to the water environment, and trials were conducted for four different application periods (1–21 days). White, red, and blue LEDs, as well as white fluorescent light, were preferred as the light environment. The results revealed that LED lights were more effective for heavy metal accumulation, with red LED light significantly enhancing the plant's phytoremediation capacity compared to other LED applications. Moreover, when examining biochemical stress parameters such as levels of photosynthetic pigments, protein concentrations, and lipid peroxidation, plants under red LED light showed better results. Generally, the lowest results were obtained under white fluorescent light. These findings contribute to phytoremediation studies by highlighting the integration of LED lights, thereby enabling the development of a more effective, cost-efficient, and environmentally sustainable remediation system compared to other treatment methods. [ABSTRACT FROM AUTHOR]

The rising heavy metal (HM) pollution in coastal aquifers in rapidly urbanizing areas such as Dammam leads to significant risks to public health and environmental sustainability, challenging compliance with Environmental Protection Agency (EPA) guidelines, World Health Organization (WHO) standards, and Sustainable Development Goals (SDGs) related to clean water and life on land. This study developed the predictive-based monitoring of HM concentrations, including cadmium (Cd), chromium (Cr), and mercury (Hg) in the coastal aquifers of Dammam, influenced by industrial, agricultural, and urban activities. For this purpose, dynamic system identification and machine learning (ML) models integrated with three ensemble techniques, namely, simple averaging (SAE), weighted averaging (WAE), and neuro-ensemble (N-ESB), were employed to enhance the accuracy, reliability, and efficiency of environmental monitoring systems. The experimental data were calibrated and validated in addition to k-fold cross-validation to ensure the predictive skills of the models. The methodology integrates extensive data collection across varied land uses in Dammam and accurate model calibration and validation phases to develop highly accurate predictive models. The findings proved that the N-ESB and Hammerstein-Wiener (HW) models surpassed other models in predicting the concentrations of all HM. For Cd, the N-ESB model achieved a root mean square error (RMSE = 0.0010 mg/kg). Similarly, Cr demonstrated superior performance (RMSE = 0.0179 mg/kg). Further numerical results indicated that the HW algorithm proved the most effective for Hg, with RMSE = 0.0000 mg/kg. The quantitative comparison suggested that the N-ESB model's consistently high performance and low error rates make it an optimal choice for real-time, precise monitoring and management of HM pollution in coastal aquifers. The outcomes of this research highlighted the importance of integrating advanced predictive modeling techniques in environmental science, providing significant and practical implications for policymaking and ecological management. [ABSTRACT FROM AUTHOR]

Landscape utilization is a green and environment-friendly way of disposing of compost sludge. Garden plants can extract heavy metals from the sludge of land use, but the effect is not enough to be widely used. Chelating agents have been found to facilitate the extraction of heavy metals from plants and are expected to be popularized if they are also environmentally friendly. In this study, the effects of methylglycinediacetic acid trisodium salt (MGDA), tetrasodium glutamate diacetate (GLDA), and ethylene diamine tetraacetate (EDTA) on the extraction of Ni and Cd from compost sludge by Symphytum officinale L. were studied through the pot experiment. Compared with the control group, the application of 5–10 mmol kg−1 MGDA and 1–9 mmol kg−1 GLDA promoted plant growth, while the application of 3–4 mmol kg−1 EDTA inhibited plant growth. The highest Ni content in shoots appeared in 4 mmol kg−1 GLDA treatment, which was 4.2 times that of the CK group. The highest shoot Cd concentration appeared in 4 mmol kg−1 EDTA treatment, 6.5 times that of CK. The promotion effects of the three reagents on the acid-extractable state of Cd were similar, while that of GLDA on the acid-extractable state of Ni was outstanding. The results of this study suggested that S. officinale could be a potential phytoextraction plant for Cd and Ni, and GLDA could friendly promote the Ni phytoextraction ability of the plant. The study provides a new and efficient method for phytoremediation of heavy metals in soil. [ABSTRACT FROM AUTHOR]

The philopatric and sedentary nature of female S. canicula, its high abundance as a bycatch and resilience to regular exploitation by bottom trawl fisheries and its widespread distribution, makes it a potentially good candidate as a biomonitor species. To evaluate this potential, microwave-assisted extraction (MAE) and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) were used to analyse Pb, Cd, and Cu in muscle tissue of individuals captured in the Western Mediterranean (Alicante, Spain). A monthly assessment of the concentration of these three analytes was conducted from November 2019 to November 2020 with 300 individuals. Results showed the existence of slightly higher mean concentrations during warmer seasons for Pb and Cd with mean concentrations for Pb and Cu peaking in Autumn 2019 and during Spring 2020 in the case of Cd. Significant differences in analyte concentrations found between non-consecutive months suggested gradual variability in time. Although space-wise, time-persistent concentration hotspots were observed throughout the sample area, the magnitude of these appeared to be variable in time and should be evaluated in future studies. [ABSTRACT FROM AUTHOR]

Marine pollution caused by heavy metals has emerged as a significant environmental concern, garnering increased attention in recent years. The accumulation of heavy metals in the tissues of marine organisms poses substantial threats to both marine ecosystems and human populations that rely on seafood as a primary food source. Fish and crustaceans are effective biomonitors for assessing heavy metal contamination in aquatic environments. In this study, we determined the concentrations of several heavy metals, including cadmium (Cd), lead (Pb), nickel (Ni), mercury (Hg), and tin (Sn), in four fish species (Mugil cephalus, Mugil capito, L. aurata, and Morone labrax) and five crustacean species (S. rivulatus, Cerastoderma glaucum, Paratapes undulatus, R. decussatus, Callinectes sapidus, and Metapenaeus Stebbingi) from Temsah Lake during both winter and summer seasons. To evaluate the potential ecological and health risks associated with consuming these fish and crustacean species, we calculated the metal pollution index (MPI), weekly intake (EWI), target hazard quotient (THQ), and carcinogenic risk (CR) values. The results revealed a noticeable increase in metal levels during the summer compared to winter in the studied samples. Moreover, the concentration of heavy metals in the muscles of the species generally exceeded those in the liver and gills. The MPI values indicated that Morone labrax exhibited the highest values during winter, while L. aurata showed the highest values during summer. Mugil cephalus demonstrated the lowest MPI values in both seasons. The EWI values for the studied metals were found to be lower than the corresponding tolerable weekly intake (TWI) values. Additionally, under average exposure conditions, the THQ and HI data were generally below one for most study species in the area. The calculated CR values for investigated metals in the studied species indicated acceptable carcinogenic risk levels. Therefore, this suggests that consuming studied species within Temsah lake does not present any potential health hazards for consumers. [ABSTRACT FROM AUTHOR]

The coal gangue dump may introduce heavy metal(oid)s (HMs) into surrounding agricultural soils, posing potential health risks to nearby communities. This study evaluated heavy metal(oid) pollution in agricultural soils adjacent to a gangue dump at an abandoned coal mine in Chongqing, Southwest China. The concentrations of HMs (As, Cd, Cr, Cu, Ni, Pb, and Zn) were quantified using ICP-MS, and the contamination status was assessed using the Geoaccumulation Index (Igeo), Contamination Factor (CF), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI). Heavy metal(oid) contamination was detected in soils across a depth of 0–30 cm, particularly pronounced in the topsoil layer (0–10 cm and 10–20 cm depths). Cu emerged as the predominant contaminant across all examined depths, with average Igeo values of 1.20, 1.21, and 1.16 for the 0–10 cm, 10–20 cm, and 20–30 cm depths, respectively, indicating moderate contamination. The CF for Cu was 3.55, 3.55, and 3.50 for these respective depths, classifying it as considerable contamination. The PLI values ranged from 1.61 to 2.50, with a mean value of 2.12, indicating overall contamination. The ecological risk assessment indicated that the soil's ecological risk was low at all depths. Cd was the major contributor to the RI, accounting for 48%, 47%, and 42% at 0–10 cm, 10–20 cm, and 20–30 cm depths, respectively. Health risk assessments revealed significant non-carcinogenic risks to children (mean HI = 1.30) and unacceptable carcinogenic risks to both adults and children (mean TCR = 3.26 × 10–4 and 1.53 × 10–3, respectively). This study underscores the critical need for comprehensive risk assessments using multiple indicators to prioritize remediation efforts for HMs, providing a scientific basis for effective environmental management and public health protection in the Three Gorges Reservoir Area. [ABSTRACT FROM AUTHOR]

In this study, four Brazilian clays (Bofe, Verde-lodo, commercial Fluidgel, and expanded commercial vermiculite) were evaluated for their adsorptive capacity and removal percentage in relation to different toxic metals (Ni2+, Cd2+, Zn2+, and Cu2+). The best results were obtained by expanded vermiculite, with cadmium removal reaching values of 95%. The most promising clay was modified by the sodification process, and the metal cadmium was used to evaluate the ion exchange process. The clays expanded vermiculite (EV) and VNa-sodified vermiculite were evaluated by equilibrium study at 25, 35, and 45 °C. At 25 °C, EV obtained a maximum adsorption capacity of 0.368 mmol/g and sodified vermiculite 0.480 mmol/g, which represents an improvement of 30.4% in modified clay capacity. At 45 °C, the sodified vermiculite reached 0.970 mmol/g adsorption capacity. The Langmuir, Redlich-Peterson Freundlich, and Dubinin-Raduskevich models were adjusted to the results. Langmuir provided the best fit among the models. The thermodynamic quantities (ΔS, ΔH, and ΔG) demonstrated that the process is spontaneous and endothermic and the metal is captured by physisorption and chemisorption in the studied temperature range. For the ion exchange equilibrium, the binary Langmuir and binary Langmuir–Freundlich models were adjusted to the expanded vermiculite and sodified vermiculite isotherms, respectively. Both models were predictive. Thermal analysis indicated good heat resistance even after material modification. The apparent and real densities demonstrated that after each treatment or contamination, the clayey material undergoes contraction in its structure. An improved efficiency of the adsorbent was found after sodification. [ABSTRACT FROM AUTHOR]

The present study investigates the synergistic impact of earthworms (Eisenia fetida and Eudrilus eugeniae) and microbes during vermicomposting of invasive weed phytomass (Xanthium strumarium and Lantana camara). This study aims introducing an onsite solution for weed control while producing valuable organic manure. Vermitransformation and detailed characterization of mono- (VC1, VC2, VC4, VC5) and polyculture (VC3, VC6) of X. strumarium and L. camara has been reported for the first time employing E. fetida and E. eugeniae. The study achieved 45.16 ± 2.48–76.73 ± 1.37% vermiconvertion rate. The pH, conductivity, and concentration of heavy metals are effectively stabilized. Furthermore, it observed a significant reduction in total organic carbon (TOC) alongside the augmentation of nitrogen, phosphorus, potassium, calcium, and other trace elements (Zn, Ni, Fe). The ash content, humification index, and C/N ratio analysis established the maturity of the vermicompost. The macronutrient enhancement in the vermicompost samples was recorded 1.5- to 2.47-fold for total N, 1.19- to 1.48-fold in available P, 1.1- to 1.2-fold in total K, and 1.1- to 1.18-fold in total Ca. The germination index reveals a significant reduction in phytotoxicity, suggesting the production of mature and suitable vermicompost for agricultural use. Evaluating mono- and polyculture techniques, the research highlights the superiority of E. fetida over E. eugeniae. Further, the earthworm population and biomass have significantly increased by the end of 60-day experimental trial. [ABSTRACT FROM AUTHOR]

Biochar is an attractive low-cost sorbent for removal of heavy metals such as cadmium (Cd) from solution. This study presents modification of sugarcane leaf biochars with phosphoric acid (H3PO4) and magnesium oxide (MgO) and the influence of Mg:P atomic ratio (varied from 0 to 2) on the Cd2+ adsorption performance was evaluated. Compared to unmodified biochar (BC), pre-pyrolysis modification with H3PO4 alone (P-BC) greatly increased the surface area from 296 to 505 m2/g but its Cd2+ adsorptivity decreased by 5-folds due to high acidity. Incorporation of alkaline MgO increased the Cd2+ adsorption and pH, despite a reduction in surface area, confirming that Mg played a predominant role in Cd2+ removal. When Mg:P > 1 (1.5MgP-BC and 2MgP-BC), more than 99% of the Cd2+ was removed, but the solutions were alkaline with pH > 8. Adsorbent 1MgP-BC presented an overall good performance with a maximum Cd2+ adsorption capacity of 36.4 mg/g (compared to 12.8 mg/g for BC) and neutral pH. The adsorption kinetics of Cd2+ onto both BC and 1MgP-BC were best described by the Elovich and pseudo-second order models, suggesting chemisorption as primary adsorption mechanism. Adsorption isotherms followed the Langmuir (for 1MgP-BC) and Freundlich isotherm models (for BC). Characterization of the post-adsorption biochars with XRD, FTIR, XPS and SEM–EDX confirmed that Cd2+ adsorption onto BC was governed by precipitation of CdCO3 and interaction with specific surface sites, whereas for 1MgP-BC the Cd2+ was primarily adsorbed onto Mg phosphates on the biochar surface and precipitated as Cd3(PO4)2. [ABSTRACT FROM AUTHOR]

Wastewater containing heavy metal ions poses great harm to human health and the environment. The adsorption materials used in traditional adsorption methods, such as starch and cellulose, are prone to hydrolysis, causing secondary pollution to water bodies. Nylon@Fe3O4@PAA adsorption material was obtained by using nylon as a substrate, activating nylon with sodium carbonate/hydrochloric acid, depositing a Fe3O4 magnetic layer by coprecipitation, and grafting polyacrylic acid. The adsorption material was used to explore the effects of different conditions (adsorption material dosage, Cu2+ concentration, pH value, and adsorption time) on the adsorption efficiency, adsorption capacity, and total adsorption amount of copper ions through changing the adsorption conditions. The research results showed that the adsorption material dosage was 31.25 mg (suspension solution with a concentration of 62.5 mg/mL was added with 300 μL), the concentration of Cu2+ solution was 20.48 mg/L, the adsorption time was 60 min, and the pH value was 9. The optimal adsorption efficiency was 82.29%, the optimal adsorption capacity was 154.87 mg/g, and the optimal total adsorption amount was 343.91 mg. After fitting thermodynamic and kinetic equations, the adsorption process of nylon@Fe3O4@PAA for Cu2+ ions dominated by chemical adsorption, with good adsorption rate and adsorption performance. [ABSTRACT FROM AUTHOR]

The access to drinkable water is a critical challenge in the context of the rising urbanization and industrialization, calling for advanced technologies to clean contaminated waters and wastewater. Here we review the use of metal oxides biochar composites to treat pollution by hevay metals and dyes. We focus on the synthesis of metal oxide nanobiochar; the treatment of pollution by mercury, lead, methylene blue and methyl orange; life cycle analysis; and techno-economical assessment. Metal oxide nanoparticles can act as photocatalysts to allow for the complete mineralization of organic pollutants. For instance, the doping of tin oxide nanoparticles into biochar surface degraded 99.5% of methylene blue dye after 105 min. Ball-milled magnetic nanobiochar achieves 99% mercury removal in 720 min. The presence of biochar enhanced the uptake of contaminants on nanoparticles and facilitated the photocatalytic reaction [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles have gained significant attention as versatile adsorbents in various studies due to their easy application, simple synthesis, cost-effectiveness, and reusability. In this study, we synthesized magnetic poly(AMA-co-GMA) nanoparticles (MAG) and modified them using allyl methacrylate (AMA) and glycidyl methacrylate (GMA). The epoxy groups on the nanoparticles were opened to introduce –OH, –NH2, and –SH functional groups. The structural properties of the synthesized nanoparticles were characterized by FTIR, their morphology by SEM–EDS, TEM, BET, and XRD, their magnetic properties by VSM, and the thermal properties by the TGA analysis. MAG and the modified nanoparticles (MAG-OH, MAG-NH2, and MAG-SH) were then employed in batch adsorption experiments for heavy metal ions, including Cd2+, Cu2+, Zn2+, Ni2+, Pb2+, and Hg2+. The effect of pH, contact time, ion concentration, and temperature on adsorption was investigated, and kinetic, isotherm, and thermodynamic parameters were determined. Pb2+ and Hg2+ exhibited higher adsorption capacities among the tested heavy metal ions, prompting further investigation with MAG and MAG-SH nanoparticles. The experimental data suggested that the adsorption followed the second order kinetic and Langmuir isotherm models. Overall, the results highlight the excellent potential of the synthesized magnetic nanoparticles for effectively removing heavy metal ions from wastewater. [ABSTRACT FROM AUTHOR]

Since the advent of industrialization, there has been a significant increase in the accumulation of heavy metals (HMs) in the soil, which further pose a major threat to plant growth and productivity. To address this issue and meet the global demand for food and energy, it is crucial to develop strategies that mitigate the toxicity induced by increased levels of HMs. One viable option is the supplementation of various phytohormones and gasotransmitters. Gasotransmitters are well-known for their ability to counteract a plethora of stresses in plants, with multifunctional hydrogen sulfide (H2S) being a promising candidate for reducing HM- induced oxidative stress. Furthermore, H2S has also been reported to regulate various physiological processes, such as seed germination, senescence and ageing in plants both under normal and stressed conditions. This review concurrently underscores the significance of H2S in plants subjected to HM stress. It also elucidates H2S's role as both a standalone stress mitigator as well as a synergistic component when combined with other stress-alleviating agents, resulting in the mitigation of HM toxicity, enhanced plant growth, stabilization of physiological processes and the upregulation of antioxidative metabolic activities. Overall, this review accentuates the necessity for sustainable and eco-friendly approaches to manage HM stress and emphasizes the potential of H2S as a promising solution to alleviate HM-related damage to plants. [ABSTRACT FROM AUTHOR]

Magnetic solid-phase extraction (MSPE) is a highly effective method for separating metal ions from aquatic solutions, making it a popular choice for metal ion separation. This study investigated the behavior of Fe3O4@SiO2-SH core–shell composites for the adsorption and recovery of silver ions. The quality of the synthesized adsorbent was verified using XRD, FT-IR, EDS, FE-SEM, and EDAX-map analyses. Magnetic properties and surface charge changes were assessed using VSM and Zeta potential analyses. By implementing the classic OFAT method, the study evaluated the effect of various parameters on silver adsorption, such as pH, composite dosage, initial Ag+ concentration, temperature, and secondary metal ions. Results showed that the proposed composite had a high maximum adsorption capacity (112 mg/g) at pH = 6, ambient temperature, 0.1 g/L adsorbent dosage, and silver concentrations greater than 25 mg/L. The composite demonstrated good selectivity in Ag+ separation from a bimetallic solution containing silver and mercury ions. The results also showed that 1M HNO3 and 1M HCl solutions released over 78% and 70% of absorbed ions from the composite surface, respectively. However, the HCl solution enabled the precipitation of almost all desorbed Ag+, providing a selective recovery of silver ions. [ABSTRACT FROM AUTHOR]

Geochemical reactions and anthropogenic activities are a source of heavy metal concentration in aquatic bodies leading to serious detrimental effect to the environment because of its non-biodegradability. Bentonite, a smectite group of minerals has layered structure based on sheets having 2:1 structure i.e. one octahedral sheet sandwiched by 2 tetrahedral sheets. The bentonite was characterised by PXRD, FTIR, TGA and DSC experiments and the surface area was known by BET analysis. A weight loss of 14% and diffraction pattern of PXRD confirmed presence of Montmorillonite unit in the inner part. Bentonite acts as a natural scavenger of heavy metal toxicants.Owing to high cation exchange capacity, high surface area and intercalation properties, bentonite mineral has been used as a potential remover of heavy metals. The kinetic and thermodynamic studies were done in order to determine the remediation potential at pH 2 to 8. Langmuir, Freundlich and Temkin adsorption isotherms were employed to give an insight into the adsorption mechanism. The experimental data revealed that first order kinetics was followed during the adsorption of heavy metals onto modified bentonite. Maximum percentage removal of Cr(VI) and Mn(VII) was 80 and 55.5 respectively. Thus locally available bentonite may be utilised as a low cost and eco-friendly alternative of heavy metal removal. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that heavy metal exposure may have adverse effects on the fetal development. Furthermore, disruption of serum hormone homeostasis can result in the adverse pregnancy outcomes. Therefore, this study aimed to investigate the potential association between heavy metals and missed abortion, with a focus on whether serum hormones mediate this relationship. The concentrations of heavy metals and hormones in serum were measured in this case–control study. Statistical models including, logistic regression model, principal component analysis (PCA), and weighted quantile sum (WQS) regression model were employed to examine the relationship between heavy metals, serum hormones, and missed abortion. Furthermore, the mediation analysis was performed to assess the role of serum hormones as potential mediators in this relationship. This study revealed significant associations between heavy metal exposure and missed abortion. Notable, the WQS index weight, which was mainly influenced by copper (Cu) and zine (Zn), is associated with missed abortion. Moreover, heavy metals including manganese (Mn), nickel (Ni), Zn, arsenic (As), Cu, cadmium (Cd), and lead (Pb) were found to be associated with serum levels of β-human chorionic gonadotropin (β-hCG), progesterone (P), estradiol (E2), and lactogen (HPL). In addition, the mediation analysis indicated that β-hCG explained a portion of the association (ranging from 18.77 to 43.51%) of between Mn, Ni, Zn, and As exposure and missed abortion. Serum P levels explained 17.93 to 51.70% of the association between Ni, Cu, and As exposure and missed abortion. Serum E2 levels played a significant mediating role, explaining a portion of the association (ranging from 22.14 to 73.60%) between Mn, Ni, Cu, As, Cd, and Pb exposure and missed abortion. Our results suggested that β-hCG, P, and E2 are one of the potential mediators in the complex relationship between heavy metals exposure and missed abortion. These results highlight the importance of considering both heavy metal exposure and serum hormone levels in understanding the etiology of missed abortion. [ABSTRACT FROM AUTHOR]

More than 70 million individuals have been exposed to environmental arsenic toxicity, worldwide. United Nation Children's Fund (UNICEF) policy brief -2018 report to mitigate arsenic in drinking water, emphasizes assessing, and changing the knowledge, attitudes, and practices (KAP) as one of the long-term effective solutions to be implemented as a part of surveillance strategies. This study aims to develop a valid and reliable tool to assess knowledge, attitude, and practices of arsenic and its risk in general health. A cross-sectional survey of N=449 general population was conducted in the outpatient department of Rajendra Memorial Research Institute of Medical Sciences-Indian Council for Medical Research for data collection. The construct validation of the questionnaire was done using Exploratory Factor Analysis, Confirmatory factor analysis. The Item-Content Validity Index(I-CVI) and Scale-Content Validity Index (S-CVI) Kappa scores were used to analyze the content validity of the items. The I-CVI ranges from 0.70 to 1, the and the moderate to high cumulative content validity is S-CVI/Universal Agreement=0.84; S-CVI/Average =0.96. Following the principal component analysis, the cumulative Kaiser-Meyer-Olkin measure of sampling adequacy (KMO) was 0.91 and the three domains in the tool (Kaiser-Meyer-Olkin measure of sampling adequacy for Knowledge (0.917), Attitude (0.825) & Practices (0.80)) were within the acceptable range. The Barret's test for sphericity was (P <0.001) and was highly acceptable. The Confirmatory Factor Analysis model of Nu-KAP has demonstrated excellent model fit where, majority of fit indices has sown good fit (X2/df=1.88, Root Mean Square Error of Approximation = 0.04, Comparative Fit Index=0.98, Goodness of Fit Index = 0.93, and Tucker Lewis Index=0.977). The Cronbach's alpha of 19 item tool was 0.72. The Nu-KAPQ questionnaire demonstrated exceptional validity and reliability while also capturing and integrating all pertinent psychometric analytic domains. Conclusively, this questionnaire can be used to assess psychometric properties associated with arsenic bridging the gap in current research to understand people's perception towards arsenic, since it is a crucial component of arsenic mitigation. [ABSTRACT FROM AUTHOR]

Shrinking agricultural land sizes and multiplied food demand have prompted overuse of fertilizers in agriculture, leading to a series of environmental repercussions worsening day after day. In the contemporary scenario, concerns over the magnitude of soil destruction and plant health have shifted the scientific community's attention toward sustainable agricultural practices, including organic farming and the use of organic fertilizers like vermicompost (VC), animal manure, etc. A factorial study using a randomized block design was conducted in the field to appraise the potential of fertilizer and irrigation water on the biochemical and growth responses of Abelmoschus esculentus using different doses of VCs along with and without recommended doses of NPK. All the biochemical analyses were performed at 45 and 65 DAG (days after germination). At both ages, combination of 3-ton ha−1 vermicompost + recommended dose of inorganic fertilizer (120:60:60 kg ha−1) + irrigation water treatments (T5) had the highest protein, chlorophyll, carotenoid, and phenol content and less lipid peroxidation as compared to control (144.28%, 84.21%, 83%, 224.2% and -60.43%, respectively). Also, T5 treatment showed a noticeable increase in the photosynthetic pigments level and reduced heavy metal content in fruits of the test plant at maturity. Statistical analyses, including PCA, Pearson correlation matrix, and MANOVA (p < 0.05), showed that appropriate dosing of VC together with inorganic fertilizer not only augments plant growth and yield, but also helps in reducing the transport of metals to different plant parts, mitigating food chain contamination. However, overdosing on fertilizers could negatively impact the plant's growth and yield. Overall, the research highlights the value of organic agricultural supplements and irrigation water quality, fostering sustainable agriculture in multifaceted ways. [ABSTRACT FROM AUTHOR]

Biodiversity commonly contributes to ecosystem functioning and provides ecosystem services. Biochar application is frequently used to remediate soils contaminated with heavy metals. As many invasive plant species can quickly form huge amounts of biomass, they are potentially useful for producing biochar for remediating contaminated soils. However, it remains untested whether invasive species richness contributes to biochar-mediated soil remediation. We applied single biochar made from each of six invasive plant species and biochar mixtures (i.e., mixtures of biochar derived from 2, 3, and 6 invasive plant species) to soils contaminated with cadmium (Cd), with no biochar application as the control. We then grew native plant communities on these soils. Compared to the control, biochar application significantly decreased Cd bioavailability (− 34% averaged across the three richness treatments) in the soils, and this effect increased with increasing invasive species richness involved in the biochar mixtures (from − 22 to − 38%). Biochar application significantly increased both the concentration (+ 126%) and pool size (+ 59%) of Cd in roots of the native plant community, although it significantly decreased its biomass (− 25%). Thus, invasive species diversity can contribute to biochar-mediated remediation of soils contaminated with Cd. Our findings indicate a novel biodiversity-mediated ecosystem service, i.e., the use of multiple invasive plant species for the production of biochar. As harvesting of invasive species for biochar production may also contribute to their management, this might mitigate the two ecological problems at once. [ABSTRACT FROM AUTHOR]

Addressing heavy metal contamination in leafy vegetables is critically important due to its adverse effects on human health. In this study, we investigated the inhibitory effects of foliar spraying with four nanoparticles (CeO2, ZnO, SiO2, and S NPs) on arsenic (As) stress in pakchoi (Brassica rapa var. Chinensis). The findings reveal that foliar application of ZnO NPs at 1 ~ 2.5 mg plant−1 and CeO2 NPs at 5 mg plant−1 significantly reduces As in shoots by 40.9 ~ 47.3% and 39.4%, respectively. Moreover, 5 mg plant−1 CeO2 NPs increased plant height by 6.06% and chlorophyll a (Chla) content by 30.2% under As stress. Foliar spraying of CeO2 NPs at 0.2–5 mg plant−1 also significantly enhanced superoxide dismutase (SOD) activity in shoots by 9.4 ~ 13.9%, lowered H2O2 content by 42.4 ~ 53.25%, and increased root protein contents by 79 ~ 109.2%. CeO2 NPs regulate the As(III)/As(V) ratio, aiding in As efflux from roots and thereby reducing As toxicity to plants. In vitro digestion experiments reveal that the consumption of CeO2 NPs carries the lowest health risk of As. In addition, foliar spraying of ZnO NPs at 1 ~ 2.5 mg plant−1 can suppress plant As uptake by modulating enzyme activity, reducing leaf damage, and enhancing chlorophyll content. The study demonstrates that high CeO2 NP concentrations and suitable ZnO NP concentrations can alleviate As toxicity in pakchoi, consequently reducing human health risks. [ABSTRACT FROM AUTHOR]

In recent years, ion-imprinted polymers have gained significant attention and are extensively utilized owing to their high selectivity toward target ions. For this research, Pb(II) ions were used as the template ions, polyamide-amine dendrimers as the curing agent, epoxy resin as the carrier and combined with ion-imprinting technique in the preparation of Pb(II)-imprinted polymer (Pb(II)-IIP). Systematic adsorption experiments were used to investigate the impact of the adsorbent on the adsorption performance of Pb(II) ions. The composition of the adsorbent was further studied by FT-IR, SEM and other characterization techniques. The maximal adsorption capacity at pH = 5 and T = 318 K was calculated to be 138.8 mg/g. In the coexistence of multiple ions, the Pb(II)-IIP showed high selectivity for Pb(II) adsorption. Pb(II) was still removed at a rate of more than 91% after five cycles of experiments, indicating good reusability. [ABSTRACT FROM AUTHOR]

The issue of heavy metal pollution is a critical global concern that requires urgent solution. However, conventional heavy metal adsorbents are too costly to be applied in large-scale engineering. In this study, adsorption behavior and mechanism of sintering red mud (RM-A) and bayer red mud (RM-B) for heavy metals were investigated to address the disposal of red mud as industrial waste and remediation of heavy metal pollution. Batch adsorption experiments were conducted to explore the adsorption performances of RM-A and RM-B under various conditions. Characterization of RM-A and RM-B before and after adsorption by XRD, FTIR and SEM-EDX was applied to investigate the specific adsorption behavior and mechanism. Adsorption experiments of both RM-A and RM-B fitted pseudo-second-order kinetic model and Langmuir isotherm model, with estimated maximum adsorption capacity of 21.96 and 25.19 mg/g for Cd2+, 21.47 and 26.06 mg/g for Cu2+ and 55.47 and 59.65 mg/g for Pb2+, respectively. Precipitation transformation of calcite was the primary adsorption mechanism for RM-A, whereas ion exchange of cancrinite, surface coordination compounds of hematite and minor precipitation transformation of calcite accounted for the adsorption mechanism for RM-B. Overall, RM-A and RM-B exhibited best adsorption performance for Pb2+, with RM-B showing greater adsorption capacity attributed to its higher specific surface area. This study compared the adsorption properties of RM-A and RM-B for the first time and demonstrated that both red muds can be effectively applied to remove heavy metals, thereby contributing to the sustainable industrial waste management and resourceful reuse. [ABSTRACT FROM AUTHOR]

Background: The Huangpu River serves as a vital water source for around 24 million individuals residing in the metropolitan area of Shanghai. Despite this, elevated levels of heavy metals persist in the sediments of the river, with their chemical fractionation and sources remaining inadequately understood. Results: To improve the management of heavy metal contamination, sequential extractions and zinc (Zn) isotopic compositions were utilized to evaluate pollution levels in the Huangpu River. The findings reveal that the majority of heavy metals in the river sediments are present in residual fractions, constituting an average of 67.5% for Cd, 57.6% for Cu, 60.6% for Ni, 56.2% for Pb, and 74.4% for Cr, with the exception of Zn (33.8%). Furthermore, a substantial portion of Zn, exceeding 66%, was found in acid-exchangeable, reducible, and oxidizable fractions, indicating a high potential for Zn release into aquatic ecosystems. Conclusion: Further analysis of Zn isotopes pinpointed traffic emissions, including exhaust fumes and tire wear particles (account for ~ 34.0%), along with anthropogenic emissions and fertilizer (~ 31.7%), as the major culprits behind this contamination. These findings highlight the critical need for stricter regulations to control heavy metal contamination from traffic and domestic sources within the Huangpu River basin. [ABSTRACT FROM AUTHOR]

A novel integrated removal strategy was developed to enhance the concurrent elimination of copper (Cu), zinc (Zn), oxytetracycline (OTC), and enrofloxacin (ENR) from the aqueous environments. The underlying adsorption mechanisms of spent mushroom substrate (SMSB) and the Herbaspirillum huttiense strain (HHS1), and their efficacy in removing Cu, Zn, OTC, and ENR was also examined. Results showed that the SMSB-HHS1 composite stabilized 29.86% of Cu and 49.75% of Zn and achieved removal rates of 97.95% for OTC and 59.35% for ENR through a combination of chemisorption and biodegradation. Zinc did not affect Cu adsorption, and ENR did not impact the adsorption of OTC on SMSB. However, the co-presence of OTC and ENR modified the adsorption behaviors of both Cu and Zn. Copper and Zn enhanced the adsorption of OTC and ENR by serving as bridging agents, facilitating the interaction between the contaminants and SMSB. Conversely, OTC and ENR inhibited the adsorption process of Cu by obstructing its interaction with the SMSB and occupying the oxygen-containing functional groups. The ‒OH (3415 cm−1) and C–O–C (1059 cm−1) functional groups were identified as the principal active sites to form hydrogen bonds and interact with Cu and Zn, leading to the formation of CuP4O11 and Zn4CO3(OH)6H2O. HHS1 also enhanced antibiotic removal through biodegradation, as evidenced by the decrease of ‒C‒O and increase of ‒C = O groups. This study underscores the innovative potential of the SMSB-HHS1 composite, offering a sustainable approach to addressing multifaceted pollution challenges in the aquatic environments. [ABSTRACT FROM AUTHOR]

Bassia indica (Wight) A. J. Scott is a fast-growing halophyte suitable for the remediation of saline lands on a large scale. However, no information is available regarding its phytoremediation potential for cadmium (Cd) alone or in combination with salinity. Besides evaluating phytoremediation, assessing micronutrient hemostasis as a crucial physiological insight into the mechanism involved in the tolerance of B. indica under saline soil contaminated with Cd was subjected. Under salinity stress, a considerable amount of sodium accumulates in the plant. Moreover, the accumulation of sodium increased by Cd stress levels. The increase in the exchangeable form of Cd in the rhizosphere in the presence of NaCl ions further elevated the Cd content in the plant tissues. For instance, compared to non-saline conditions, applying 2.5 and 5 g NaCl kg−1 to soil treated with 60 mg Cd kg−1 increased exchangeable Cd by 28.4 and 49.5% in rhizosphere soil, which led to increased cadmium content by 16.1 and 29.6% in the root (as a main part of Cd accumulation), respectively. Under most stress conditions, potassium homeostasis in the shoot remained undisturbed. It was observed that this plant could transfer an optimal level of potassium from the roots to the shoots at a moderate salinity level. Changes and the distribution of Cu and Zn levels followed a similar pattern in the plant, indicating a common regulation mechanism for these nutrients. Generally, the plant could maintain an appropriate level of Fe, Zn, and Cu ions under most stressed conditions. However, the level of Mn decreased significantly under severe stress levels. Growth parameters, tolerance index, and the values of translocation factor < 1 and shoot bioconcentration factor > 1 under 5 mg Cd kg−1 soil treatment at different salinity levels indicated that B. indica could mitigate the detrimental effect of Cd toxicity and tolerate the NaCl stress via a phytostabilizer mechanism. However, the shoot bioconcentration factor values were very close to one at other Cd levels. Therefore, considering the obtained evidence and the innate ability of B. indica to remediation salinity, this plant is still recommended, even for higher Cd levels (even until 30 mg kg−1), in the presence of salinity. [ABSTRACT FROM AUTHOR]

Soil-bentonite (S-B) barriers have been widely used for heavy metal pollution containment. This study conducted batch adsorption tests and diffusion-through tests to evaluate how ionic strength and bentonite ratio influence the migration of Cr(VI) in natural clay-bentonite mixtures. The test results indicated that the adsorption of Cr(VI) exhibited an obvious anion adsorption effect, the pH of the soil mixture increased with the addition of bentonite, resulting in a decrease in the positive surface charge. This change led to a decrease in Cr(VI) adsorption capacity, from 775.19 mg/kg for pure clay to 378 mg/kg for mixture samples with excessive bentonite. Furthermore, as the ionic strength increases from 0 to 0.1 M, the Cr(VI) adsorption capacity increases slightly due to the weakening of electrostatic repulsion on the clay particle surface, but the effective diffusion coefficient (De) increases by 21.97%. The compression of the diffusion double layer (DDL) under high ionic strength conditions enlarges the diffusion path and enhances the migration of Cr(VI) through the pore flow paths. Moreover, hydrated bentonite effectively fills the interaggregate pores of natural clay, thus creating narrower and more tortuous flow paths. However, excessive bentonite increases the pH value and pore volume, resulting in changes to the soil microstructure and disrupting the continuous skeleton of natural clay, which is unfavorable for Cr(VI) containment. Based on the study of the Cr(VI) contaminated site, a bentonite ratio of 2:10 is recommended for optimal natural performance of the natural clay-bentonite barrier. [ABSTRACT FROM AUTHOR]