Properties and environmental quality of the overburden and tailings of manganese mining in the Eastern Amazon.

Knowledge about the characteristics of overburden and tailings from manganese (Mn) mining is essential for defining their levels of potentially toxic elements (PTEs) and appropriate environmental management. This study aimed to assess the total and bioavailable contents of PTEs in Mn mining areas in the Eastern Amazon, as well as the associated environmental risks. The samples were collected in areas of overburden and tailings deposition, in addition to forest soils in the Azul mine, Carajás Mineral Province, Brazil. These samples were characterized in terms of fertility, granulometry, and total and bioavailable PTE contents. The pH values of the forest soil were more acidic than those of the overburden and tailings, and the organic matter contents were considerably higher in the forest soil. All PTEs, especially Mn, Ba, Cu, Zn, and Pb, presented higher contents in the overburden and tailings. However, chemical fractionation revealed that PTEs were predominantly in the residual fraction, with percentage contents above 60% of the total content. These results suggest a low risk of environmental contamination. The findings of this study may support more efficient environmental rehabilitation in Mn mining areas in the Amazon.

Effect of various phosphorus levels on the extraction of Cd, the transformation of P, and phosphorus-related gene during the phytoremediation of Cd contaminated soil.

Phytoremediation has emerged as a common technique for remediating Cd pollution in farmland soil. Moreover, phosphorus, an essential element for plants, can alter the pectin content of plant cell walls and facilitate the accumulation of Cd in plant tissues, thereby enhancing phytoremediation efficiency. Therefore, pot experiments were conducted in order to investigate the effect of phosphorus levels on Cd extraction, phosphorus transformation and phosphorus-related genes during phytoremediation. The results revealed that an optimal application of suitable phosphate fertilizers elevated the soil's pH and electrical conductivity (EC), facilitated the conversion of soil from insoluble phosphorus into available forms, augmented the release of pertinent enzyme activity, and induced the expression of phosphorus cycling-related genes. These enhancements in soil conditions significantly promoted the growth of ryegrass. When applying phosphorus at a rate of 600 mg/kg, ryegrass exhibited plant height, dry weight, and chlorophyll relative content that were 1.27, 1.26, and 1.18 times higher than those in the control group (P0), while the Cd content was 1.12 times greater than that of P0. The potentially toxic elements decline ratio and bioconcentration factor were 42.86% and 1.17 times higher than those of P0, respectively. Consequently, ryegrass demonstrated the highest Cd removal efficiency under these conditions. Results from redundancy analysis (RDA) revealed a significant correlation among pH, total phosphorus, heavy metal content, phosphorus forms, soil enzyme activity, and phosphorus-related genes. In conclusion, this study suggests applying an optimal amount of suitable phosphate fertilizers can enhance restoration efficiency, leading to a reduction in soil Cd content and ultimately improving the safety of crop production in farmlands.

Occurrence, dietary influence and risks of selected trace metals in different coastal predatory species.

The global issue of ongoing trace metal emissions and legacy accumulation from diverse sources is posing threats to coastal wildlife. This study characterized the distribution of five metals in relation to dietary ecology (carbon and nitrogen stable isotopes: δ15N and δ13C) in representative predatory species (starfish, fish, and seabird) collected from the coast of Qingdao, northeastern China. Zinc (Zn) was the most abundant metal across species, followed by copper (Cu), chromium (Cr), cadmium (Cd), total and methylated mercury (THg and MeHg). Among the studied species, black-tailed gulls (Larus crassirostris) occupied the highest trophic position, followed by three predatory fish species, whereas the northern Pacific seastar (Asterias amurensis) had the lowest trophic position. The starfish exhibited high capacity to accumulate Cd, Cr and Cu. Conversely, black-tailed gulls exhibited high levels of Zn, while Hg was highest in predatory fishes. Across species, Cr, MeHg, THg and MeHg:THg showed significant positive correlations with δ13C, suggesting the influence of inshore food sources on their accumulation. Both MeHg and THg were significantly and positively correlated with δ15N, with MeHg demonstrating a greater slope, indicating their potential trophic magnification. We assessed health risks from the studied metals using established toxicity reference thresholds. Elevated risks of Hg were identified in three predatory fish species, while other metals and species remain within safe limits. These findings emphasize the significance of foraging patterns in influencing trace metal accumulation in coastal predators and highlight the importance of further monitoring.

Toxic element characterization against a typical high geology background: Pollution enrichment, source tracking, spatial distribution, and ecological risk assessment.

The geological environment determines the initial content of various elements in soil, while the late input of toxic elements produced through weathering and leaching is a persistent threat to food security and human health. In this study, we selected the Lou Shao Basin, a black rock system background, and combined geostatistical analysis and multivariate statistics to quantify the specific contribution of weathering of the black rock system, and to analyze the source traces, spatial distributions, and ecological risks of the soil toxicity of elements. The results show that the soils in the study area are acidic, which is related to the weathering of sulfides in the black rock system. The concentrations of most elements in the soil were determined to exceed the soil background values, and the Cd, Se and N contents, exceeded more than five times, especially Se, Mo nearly as high as 13 times. Strong positive correlation between Se, Cu, V and P, low correlation between N and Se, Cu, V, P, Ni and Cd.72.52%, 43%, 77.79%, 82%, 77%, and 44.1% of Cd, Se, Ni, Cu, B, and Mo came from the black rock system, respectively, which were greatly affected by geogenic weathering; V, Zn, Pb, and As are mainly from biomass burning sources; N and P are mainly from agricultural surface sources. Comparison found that the Cd and Se elements in the rocks in the study area were 16.78 times and 1.36 times higher than the world shale average, respectively, and need to pay attention to the weathering process of the two, and the spatial distribution of the 12 elements in soils showed a striped and centralized block distribution pattern, specifically around the distribution of carbonate and metamorphic rocks and other high-geology blocks. The ecological risk results showed that Cd was the main element causing high ecological risk, followed by Se and N, which were at moderate to high ecological risk levels, and Se and N showed similar ecological risk patterns, which may be related to the fact that selenium can promote the uptake and transformation of nitrogen. The present results add to the endogenous sources of toxic elements, quantify the source contributions of toxic elements in soils with high geologic backgrounds, fill this knowledge gap, and provide new insights for pollution control and ecological protection in areas with high geochemical backgrounds.

Heavy metals and trace minerals in commonly available shark species from North East Arabian Sea: A human health risk perspective.

Shark is a seafood commodity that is a good source of minerals and accumulates heavy metals and trace elements through biomagnification, which can pose health risk if taken above the permissible limit. A study was conducted on commonly landed eleven shark species (Scoliodon laticaudus, Rhizopriodon oligolinx, Sphyrna lewini (CR), Carcharhinus macloti, Carcharinus limbatus, Carcharhinus amblyrhynchoides, Carcharhinus sorrah, Carcharinus falciformes(VU), Glaucostegus granulatus, Chiloscyllium arabicum, Loxodon macrorhinus) and analyzed for their heavy metal content, Hazard Index, Total Hazard Quotient, Metal Pollution Index, and also calculated the health risk associated with the consumption. Most of the heavy metals and trace minerals were found to be within the acceptable limit. The Targeted Hazard Quotient (THQ) and the Hazard Index (HI) of all the species except two were less than 1 (HI ≤ 1.0). The Metal Pollution Index (MPI) is showing either no impact or very low contamination. An overall study on hazard identification and health risk characterization in terms of heavy metals shows contamination of some heavy metals in sharks, but there is no potential human health risk associated with consumption.

A probabilistic health risk assessment of potentially toxic elements in edible vegetable oils consumed in Hamadan, Iran.

In this study, potential toxic element (PTEs) including lead (Pb), arsenic (As), cadmium(Cd), iron (Fe) and zinc (Zn) in traditional and industrial edible vegetable oils (peanut, sunflower, olive and sesame) collected from Hamadan, west of Iran were determined using Inductivity Coupled Plasma Optical Emission Spectrometry (ICP-OES). Besides, probabilistic health risk assessment (non-carcinogenic and carcinogenic risks) was identified via total target hazard quotient (TTHQ) and cancer risk (CR) by the Monte Carlo Simulation (MCS) model. The ranking of concentration PTEs in traditional and industrial edible vegetable oils was Fe > Zn > As > Pb > Cd. The in all samples, content of PTEs in industrial oils were upper than traditional oils (p < 0.001). The level of PTEs in most of vegetable oils was lower than permissible concentration regulated by Codex and national standard. In term of non-carcinogenic, consumers were at acceptable range (TTHQ < 1) due to ingestion both traditional and industrial vegetable oils content of PTEs. In term of carcinogenic, CR the both adults and children was higher than acceptable range (CR < 1E-6), Hence consumer are at unacceptable risk due to ingestion industrial vegetable oils content of inorganic As. Therefore, it is recommended to implement control plans for PTEs in vegetable oils consumed in Hamadan, Iran.

Elements in Serum, Muscle, Liver, and Kidney of Rabbits Fed Macroalgae-Supplemented Diets.

The addition of marine macroalgae to animal feed has garnered interest due to the demonstrated benefits of gut health in many livestock species. Most macroalgae have a higher mineral content than terrestrial vegetables, making them an attractive, sustainable source of minerals. However, some macroalgae contain elevated concentrations of iodine and arsenic, which may be transferred to the meat of livestock fed with macroalgae. This study evaluated the mineral profile of rabbit serum, muscle, liver, and kidney of rabbits fed diets supplemented with different marine macroalgae, with the goal of improving post-weaning gut health and reducing reliance on antibiotics. We found increased deposition of iodine in muscle, liver, and kidney due to macroalgae supplementation, which is particularly promising for regions with low iodine endemicity. Higher, though relatively low arsenic concentrations, compared to those in other animal meats and food sources, were also detected in the muscle, liver, and kidney of macroalgae-fed rabbits. The absence of apparent interactions with other micronutrients, particularly selenium, suggests that the inclusion of macroalgae in rabbit diets will not affect the overall mineral content. Enhanced bioavailability of elements such as phosphorus and iron may provide additional benefits, potentially reducing the need for mineral supplementation.

Necrophagous flies as bioindicators in Cd and Zn co-contaminated areas of Tak Province, Thailand.

Necrophagous flies may be effective bioindicators of chemical substances within polluted locations, as they are sensitive to environmental changes, have large populations, and thrive in a single location over their lifespan. Diversity and abundance of necrophagous flies were determined at livestock farms contaminated with potentially toxic elements (PTEs) in Tak Province and Nakhon Sawan Province, Thailand. Substantial soil zinc (Zn) concentrations (> 1100 mg kg-1) were detected at a cattle farm at Khaothong, Nakhon Sawan Province, and soil cadmium (Cd) values were significantly elevated (> 3 mg kg-1) at a cattle farm in Pha De, Tak Province. Anthropogenic inputs including Zn mining, domestic wastewater, and certain materials used in local agriculture were point sources of PTEs at the livestock farms in the Pha De and Khaothong subdistricts. Lower temperatures and humidity during the rainy season may have resulted in increased numbers of necrophagous flies, which was 1.5 times greater compared to the dry season. However, the dry season exhibited a higher PTE buildup in fly tissue. The order of important value index (IVI) values of the necrophagous flies were: Chrysomya megacephala (56.80), Musca domestica (27.21), C. rufifacies (25.40) and Sarcophaga spp. (17.54), respectively. These necrophagous flies may play a significant role in PTE-contaminated ecosystems based on their high IVI values, suggesting that they could be used as bioindicators of PTEs. Principal component analysis (PCA) results for necrophagous flies associated with each sampling site during the dry season were consistent with flies having substantial IVI values. Musca domestica and C. megacephala of both sexes displayed substantial correlations with Cr, Al, and Mn, while females of Sarcophaga spp. displayed strong associations with Cd. At the cattle farm in Khaothong, males of M. domestica showed a significant relationship with Zn, Cu, Pb, and Ni. When considering PTE accumulation capacity in flies commonly found at field sites, C. megacephala and M. domestica are the most suitable bioindicators of PTEs. This study confirms that necrophagous flies serve as reliable bioindicators of PTE pollution.

A comprehensive assessment of heavy metals, VOCs and petroleum hydrocarbon in different soil layers and groundwater at an abandoned Al/Cu industrial site.

Compound pollution at industrial sites impedes urban development, especially when there is a lack of understanding about the spatial variations of internal pollution in industrial areas producing light-weight materials. In this study, spatial distribution and ecological risks of potentially toxic elements (PTEs), volatile organic compounds (VOCs), and petroleum hydrocarbons (C10-40) in the soil and groundwater of an Al/Cu (aluminum/copper) industrial site have been analyzed comprehensively. Results revealed the progressive clustering of pollutants in different soil layers, which indicated varying levels of penetration and migration of pollutants from the surface downward. Furthermore, severity of pollution varied according to pollutant type, with Cu (5-10,228 mg kg-1) often exceeding the background levels significantly (>40). Cd (0.03-2.60 mg kg-1) and Hg (0.01-3.73 mg kg-1) were found at elevated concentrations in deeper soil layers, suggesting distinct variations of PTEs across different soil depths. Among the more hazardous VOCS, polychlorinated biphenyls (1.80-234 µg kg-1) were particularly prevalent in the deeper layers of soil. Petroleum hydrocarbons (C10-40) were widely detected (6-582 mg kg-1), showing significant migration potential from surface to deep soil. These findings suggest that prolonged industrial activities lead to deep-seated accumulation of pollutants, which also impacts the groundwater, contributing to long-term dispersion of contaminants. Furthermore, multivariate statistical analysis indicated certain positive correlations among the distribution of Cu, Pb and petroleum hydrocarbons, indicating possible coupling of these pollutants. Severe Cu pollution caused an ecological risk in the surface soil layer (covering >20 % area of high pollution site, contributing >40 % ecological risk). While the Hg and Cd posed significant risks in the deeper soil layers, showing higher risk coefficients and mobility. The study provides crucial insights into the transformation of urban areas with a history of industrial uses into community spaces and highlights the risks posed by the remaining pollutants.

Pollution sources and risk assessment of potentially toxic elements in soils of multiple land use types in the arid zone of Northwest China based on Monte Carlo simulation.

The concentration of potentially toxic elements (PTEs) in soils of different land-use types varies depending on climatic conditions and human. Topsoil samples were collected in Northwest China to investigate PTE pollution and risk in different land uses, and thereby estimate the risk of various pollution sources. The results showed that human activity had an impact on PTE concentrations in the study area across all land use types, with farmland, grassland, woodland, and the gobi at moderate pollution levels and the desert at light pollution levels. Different PTE sources pose different risks depending on the land-use type. Apart from deserts, children are exposed to carcinogenic risk from a variety of sources. A mixed natural and agricultural source was the main source of public health risk in the study area, contributing 38.7% and 39.0% of the non-carcinogenic and 40.7% and 35.5% of the carcinogenic risks, respectively. Monte Carlo simulations showed children were at a higher health risk from PTEs than adult s under all land uses, which ranked in severity as farmland > woodland > grassland > gobi > desert. As and Ni has a higher probability of posing both a non-carcinogenic and a carcinogenic risk to children. Sensitivity analysis showed that the contribution of parameters to the assessment model of PTEs exhibited the following contribution pattern: concentration > average body weight > ingestion rate > other parameters. The PTEs affecting the risk assessment model were not common among different land use types, where the importance distribution pattern of each parameter was basically the same in woodland, grassland, and farmland, and Ni contributed the most to carcinogenic risk. However, Cr contributed the most to the carcinogenic risk in the desert and gobi.

Removal of potentially toxic elements from water with the moss-tufa micro-filtration system.

Mosses are an integral component in the tufa sedimentary landscape. In this study, we investigated the use of the porous moss-tufa structure as a filtration system for removing potentially toxic elements (PTEs) from water samples. Three species of mosses that commonly grow on tufa were selected, and the PTEs filtered by the moss-tufa system were identified by inductively coupled plasma mass spectrometry. The bioconcentration factor (BCF) of mosses was calculated to compare the enrichment effects of different mosses on PTEs. Likewise, the level of PTEs flowing through the moss-tufa system was measured, and the water quality removal rate (C) was calculated accordingly. The results revealed that the moss-tufa system was mainly composed of Fissidens grandifrons Brid., Hydrogonium dixonianum P. C. Chen, and Cratoneuron filicinum (Hedw.) Spruce var. filicinum. Among these, Fissidens grandifrons Brid. reported the highest retention capacity for PTEs. Collectively, the moss-tufa filtration system displayed a strong retention capacity and removal rate of Mn, Pb, and Ni from the water sample. The removal of PTEs by the moss-tufa system was mainly based on the enrichment of mosses and the adsorption-retention ability of tufa. In conclusion, the moss-tufa micro-filtration system displayed the effective removal of PTEs from water samples and could be applied to control the levels of toxic elements in karst water bodies.

Major influencing factors identification and probabilistic health risk assessment of soil potentially toxic elements pollution in coal and metal mines across China: A systematic review.

Deposition of potentially toxic elements (PTEs) in soils due to different types of mining activities has been an increasingly important concern worldwide. Quantitative differences of soil PTEs contamination and related health risk among typical mines remain unclear. Herein, data from 110 coal mines and 168 metal mines across China were analyzed based on 265 published literatures to evaluate pollution characteristics, spatial distribution, and probabilistic health risks of soil PTEs. The results showed that PTE levels in soil from both mine types significantly exceeded background values. The geoaccumulation index (Igeo) revealed metal-mine soil pollution levels exceeded those of coal mines, with average Igeo values for Cd, Hg, As, Pb, Cu, and Zn being 3.02-15.60 times higher. Spearman correlation and redundancy analysis identified natural and anthropogenic factors affecting soil PTE contamination in both mine types. Mining activities posed a significant carcinogenic risk, with metal-mine soils showing a total carcinogenic risk an order of magnitude higher than in coal-mine soils. This study provides policymakers a quantitative foundation for developing differentiated strategies for sustainable remediation and risk-based management of PTEs in typical mining soils.

Integrated assessment of potentially toxic elements in soil of the Kangdian metallogenic province: A two-point machine learning approach.

The accumulation of potentially toxic elements in soil poses significant risks to ecosystems and human well-being due to their inherent toxicity, widespread presence, and persistence. The Kangdian metallogenic province, famous for its iron-copper deposits, faces soil pollution challenges due to various potentially toxic elements. This study explored a comprehensive approach that combinescombines the spatial prediction by the two-point machine learning method and ecological-health risk assessment to quantitatively assess the comprehensive potential ecological risk index (PERI), the total hazard index (THI) and the total carcinogenic risk (TCR). The proportions of copper (Cu), cadmium (Cd), manganese (Mn), lead (Pb), zinc (Zn), and arsenic (As) concentrations exceeding the risk screening values (RSVs) were 15.03%, 5.1%, 3.72%, 1.24%, 1.1%, and 0.13%, respectively, across the 725 collected samples. Spatial prediction revealed elevated levels of As, Cd, Cu, Pb, Zn, mercury (Hg), and Mn near the mining sites. Potentially toxic elements exert a slight impact on soil, some regions exhibit moderate to significant ecological risk, particularly in the southwest. Children face higher non-carcinogenic and carcinogenic health risks compared to adults. Mercury poses the highest ecological risk, while chromium (Cr) poses the greatest health hazard for all populations. Oral ingestion represents the highest non-oncogenic and oncogenic risks in all age groups. Adults faced acceptable non-carcinogenic risks. Children in the southwest region confront higher health risks, both non-carcinogenic and carcinogenic, from mining activities. Urgent measures are vital to mitigate Hg and Cr contamination while promoting handwashing practices is essential to minimize health risks.

Soil amendment-assisted phytoremediation with ryegrass offers a promising approach to mitigate environmental health concerns.

This study aimed to examine the potential of soil amendment-assisted phytoremediation using ryegrass in reclaiming abandoned gold mine soil in southwestern Ghana, with a specific focus on the soil contamination hazards associated with metals and metalloids. A pot experiment lasting 60 days was carried out to assess the efficacy of soil amendments, such as compost, iron oxide, and poultry manure, in mitigating environmental hazards. Three soil contamination indices (soil contamination = CF, enrichment factor = ER, and pollution load index = PLI) were used to calculate the extent of soil contamination, enrichment, and pollution of the sites with Co, Hg, Ni, Mo, Se, Sb, and Pb. The findings show that Hg made the greatest contribution (with a maximum soil CF of 18.0) to the overall PLI, with a maximum value of 74.4. The sites were averagely and consequently enriched with toxic elements in the decreasing order: Ni (ER = 33.3) > Mo (20.5) > Sb (14.1) > Pb (11.0) > Hg (7.9) > Se (2.1). The bioaccumulation factor (BCF > 1) suggests that ryegrass has the ability to phytostabilize Co, Hg, Mo, and Ni. This means that the plant may store these elements in its roots, potentially decreasing their negative effects on the environment and human health. Ultimately, the addition of combined manure with iron oxides might have augmented the sequestration of these metals in the root. The elements may have accumulated through sorption on manure or Fe surfaces, dissolution from watering the plants in the pot, or mineralization of organic manure. Thus, ryegrass has shown potential for phytostabilisation of Co, Hg, Mo, and Ni when assisted with a combination of manure and iron oxides; and can consequently mitigate the environmental and human health impacts.

Gold mining in Ghana has caused significant environmental damage and political unrest. Research on environmentally friendly solutions to land degradation is crucial for restoring degraded lands, preserving ecosystem integrity, restoring livelihoods, and protecting public health in gold mining hotspots. However, previous studies have often overemphasized the use of trees in improving soil quality. Other past studies have merely collected plant species for heavy metal analysis without concrete pots or field experiments. Ryegrass has only been limited to arsenic remediation, and its phytoremediation ability for other toxic elements like Co, Hg, Mo, Ni, Pb, Sb, and Se has not been investigated. This work reports for the first time the phytostabilisation ability of ryegrass for potentially toxic elements in a Ghanaian context. Consequently, recommendations are made for reclaiming gold-mine-affected sites while at the same time providing evidence for widening the choice of plant species available for restoring mine-derelict lands. Ultimately, the study fills the gap in phytoremediation research within the global scientific community and Ghana in particular.

Ladle slag-based binder for the solidification/stabilization of heavy-metal-rich industrial waste.

Heavy metal pollution from industrial sources is a major environmental and health hazard on a global scale. This study introduces a solidification/stabilization method of industrial waste using a waste-based, ettringite-rich solid binder from ladle slag and gypsum for the immobilization of an industrial waste material with extremely high contents of several heavy metals. The importance of sulfate and water content on the immobilization efficiency and the use of citric acid to increase the processing time of the binder were studied. The leaching of Pb, Hg, Se, As, Cd, Cu, and Ni was measured, and X-ray powder diffraction, field-emission scanning electron microscopy, and field-emission electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy were used to analyze the structure of the hardened binder and the location of the heavy metals within. The study shows that the ladle slag/gypsum binder is suitable for the solidification/stabilization of heavy-metal-rich solid industrial waste. Hg, As, Cd, Cu, and Ni were fully immobilized in all scenarios covered in the study, whereas Pb and Se showed more complicated behaviors. The main immobilization method was encapsulation, and partial Se incorporation into ettringite was observed. The presence of citric acid increased the processing time of the binder without harming the immobilization, unless combined with low sulfate content.

Enhanced Removal of Cd(II) Ions from Aqueous Media via Adsorption on Facilely Synthesized Copper Ferrite Nanoparticles.

In this study, magnetic copper ferrite (CuFe2O4) nanoparticles were synthesized via the Pechini sol-gel method and evaluated for the removal of Cd(II) ions from aqueous solutions. PF600 and PF800 refer to the samples that were synthesized at 600 °C and 800 °C, respectively. Comprehensive characterization using FTIR, XRD, FE-SEM, HR-TEM, and EDX confirmed the successful formation of CuFe2O4 spinel structures, with crystallite sizes of 22.64 nm (PF600) and 30.13 nm (PF800). FE-SEM analysis revealed particle diameters of 154.98 nm (PF600) and 230.05 nm (PF800), exhibiting spherical and irregular shapes. HR-TEM analysis further confirmed the presence of aggregated nanoparticles with average diameters of 52.26 nm (PF600) and 98.32 nm (PF800). The PF600 and PF800 nanoparticles exhibited exceptional adsorption capacities of 377.36 mg/g and 322.58 mg/g, respectively, significantly outperforming many materials reported in the literature. Adsorption followed the Langmuir isotherm model and pseudo-second-order kinetics, indicating monolayer adsorption and strong physisorption. The process was spontaneous, exothermic, and predominantly physical. Reusability tests demonstrated high adsorption efficiency across multiple cycles when desorbed with a 0.5 M ethylenediaminetetraacetic acid (EDTA) solution, emphasizing the practical applicability of these nanoparticles. The inherent magnetic properties of CuFe2O4 facilitated easy separation from the aqueous medium using a magnet, enabling efficient and cost-effective recovery of the adsorbent. These findings highlight the potential of CuFe2O4 nanoparticles, particularly PF600, for the effective and sustainable removal of Cd(II) ions from water.

Effective Removal of Different Heavy Metals Ion (Cu, Pb, and Cd) from Aqueous Solutions by Various Molecular Weight and Salt Types of Poly-γ-Glutamic Acid.

In light of industrial developments, water pollution by heavy metals as hazardous chemicals has garnered attention. Addressing the urgent need for efficient heavy metal removal from aqueous environments, this study delves into using poly-γ-glutamic acid (γ-PGA) for the bioflocculation of heavy metals. Utilizing γ-PGA variants from Bacillus subtilis with different molecular weights and salt forms (Na-bonded and Ca-bonded), the research evaluates their adsorption capacities for copper (Cu), lead (Pb), and cadmium (Cd) ions. It was found that Na-bonded γ-PGA with a high molecular weight showed the highest heavy metal adsorption (92.2-98.3%), particularly at a 0.5% concentration which exhibited the highest adsorption efficiency. Additionally, the study investigated the interaction of γ-PGA in mixed heavy metal environments, and it was discovered that Na-γ-PGA-HM at a 0.5% concentration showed a superior adsorption efficiency for Pb ions (85.4%), highlighting its selectivity as a potential effective biosorbent for wastewater treatment. This research not only enlightens the understanding of γ-PGA's role in heavy metal remediation but also underscores its potential as a biodegradable and non-toxic alternative for environmental cleanup. The findings pave the way for further exploration into the mechanisms and kinetics of γ-PGA's adsorption properties.

Assessment of Microplastics and Potentially Toxic Elements in Surface Sediments of the River Kelvin, Central Scotland, United Kingdom.

Contamination of the environment by microplastics (MPs), polymer particles of <5 mm in diameter, is an emerging concern globally due to their ubiquitous nature, interactions with pollutants, and adverse effects on aquatic organisms. The majority of studies have focused on marine environments, with freshwater systems only recently attracting attention. The current study investigated the presence, abundance, and distribution of MPs and potentially toxic elements (PTEs) in sediments of the River Kelvin, Scotland, UK. Sediment samples were collected from eight sampling points along the river and were extracted by density separation with NaCl solution. Extracted microplastics were characterised for shape and colour, and the polymer types were determined through attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Pollution status and ecological risks were assessed for both the microplastics and PTEs. Abundance of MPs generally increased from the most upstream location (Queenzieburn, 50.0 ± 17.3 particles/kg) to the most downstream sampling point (Kelvingrove Museum, 244 ± 19.2 particles/kg). Fibres were most abundant at all sampling locations, with red, blue, and black being the predominant colours found. Larger polymer fragments were identified as polypropylene and polyethylene. Concentrations of Cr, Cu, Ni, Pb and Zn exceeded Scottish background soil values at some locations. Principal component and Pearson's correlation analyses suggest that As, Cr, Pb and Zn emanated from the same anthropogenic sources. Potential ecological risk assessment indicates that Cd presents a moderate risk to organisms at one location. This study constitutes the first co-investigation of MPs and PTEs in a river system in Scotland.

The concentration of potentially toxic elements (PTEs) in honey: Global systematic review and meta-analysis and risk assessment.

The papers were searched in databases including PubMed, Scopus, Web of science, Embase, Science Direct until 21 September 2023 and meta-analysis of concentration of PTEs in honey was performed using random effects model based on country subgroups. The non-carcinogenic risk and carcinogenic risk were calculated by Target Hazard Quotient (THQ) and Cancer Risk (CR), respectively. The sort of PTEs in honey based on pooled concentration was Cu (1.10E + 02 µg/kg) > Ni (1.80E + 01 µg/kg) > Pb (2.60E + 00 µg/kg) > Hg (1.50E + 00 µg/kg) > Cd (5.10E-01 µg/kg) > As (4.80E-01 µg/kg). The concentration of PTEs in the countries of Ethiopia (As), Jordan (Cd and Pb), Thailand (Ni), Brazil (Cu and MeHg) was observed to be higher than other countries. The non-carcinogenic risk was less than 1, hence, the consumption of honey does not have non-carcinogenic risk. Except children in Nigeria, CR due to iAs in honey was acceptable for the both adults and children in the other countries, Therefore, the consumption of honey does not have carcinogenic risk.

Bioaccumulation of potentially toxic elements in leafy and tuberous vegetables: a comparison based on meta-analysis studies with a cumulative health risk assessment.

Seventy seven research papers published from 1986 to 2018 were observed. These papers investigated PTEs (Pb, Cd, Cu, As, Fe, Zn, Ni, and total Cr) in leafy (mint, spinach, coriander, and lettuce) and tuberous (potato, carrot, radish, and onion) vegetables irrigated by wastewater. The studies observed in our paper were conducted in 19 countries. The PTEs concentrations were compared among studies and the human health risk was observed. According to the obtained meta-analysis results, PTEs concentrations (mg/kg) in vegetables were found in the following order Zn (34.216)> Cu (22.581)> Ni (14.056)> Pb (10.173)> Cr (8.308)> Fe(8.130)> As(1.881)> Cd (1.763). Hazard index for children was higher than that for adults and for both groups, the calculated HQ was higher than 1, which indicates that there is a health risk for the consumers. This study provides a comprehensive analysis that demonstrates the urgent necessity for treating PTE pollution in agricultural areas worldwide.