Search Results (59)

Potentially toxic elements such as cadmium (Cd) in agricultural soils represent a global concern due to their toxicity and potential accumulation in the food chain. However, our understanding of cadmium’s complex sources and the mechanisms controlling its spatial distribution across diverse edaphic and geological contexts remains limited, particularly in underexplored agricultural regions. Our study aimed to assess the total accumulated Cd content in soils under avocado cultivation and its association with edaphic, geochemical, and geomorphological variables. To this end, we considered the total concentrations of other metals and explored their associations to gain a better understanding of Cd’s spatial distribution. We analyzed 26 physicochemical properties, the total concentrations of 22 elements (including heavy and trace metals such as As, Ba, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sr, Tl, V, and Zn and major elements such as Al, Ca, Fe, K, Mg, and Na), and six geospatial variables in 410 soil samples collected from various avocado-growing regions in Peru in order to identity potential associations that could help explain the spatial patterns of Cd. For data analysis, we applied (1) univariate statistics (skewness, kurtosis); (2) multivariate methods such as Spearman correlations and principal component analysis (PCA); (3) spatial modeling using the Geodetector tool; and (4) non-parametric testing (Kruskal–Wallis test with Dunn’s post hoc test). Our results indicated (1) the presence of hotspots with Cd concentrations exceeding 3 mg·kg⁻¹, displaying a leptokurtic distribution (skewness = 7.3); (2) dominant accumulation mechanisms involving co-adsorption and cation competition (Na⁺, Ca²⁺), as well as geogenic co-accumulation with Zn and Pb; and (3) significantly higher Cd concentrations in Leptosols derived from Cretaceous intermediate igneous rocks (diorites/tonalites), averaging 1.33 mg kg⁻¹ compared to 0.20 mg·kg⁻¹ in alluvial soils (p < 0.0001). The factors with the greatest explanatory power (q > 15%, Geodetector) were the Zn content, parent material, geological age, and soil taxonomic classification. These findings provide edaphogenetic insights that can inform soil cadmium (Cd) management strategies, including recommendations to avoid establishing new plantations in areas with a high risk of Cd accumulation. Such approaches can enhance the efficiency of mitigation programs and reduce the risks to export markets. Full article

This review systematically examines the critical mechanisms and process optimization strategies of algal–bacterial granular sludge (ABGS) technology in wastewater treatment. The key findings highlight the following: (1) enhanced pollutant removal—ABGS achieves >90% COD removal, >80% total nitrogen elimination via nitrification–denitrification coupling, and 70–95% phosphorus uptake through polyphosphate-accumulating organisms (PAOs), with simultaneous adsorption of heavy metals (e.g., Cu²⁺, Pb²⁺) via EPS binding; (2) energy-saving advantages—microalgal oxygen production reduces aeration energy consumption by 30–50% compared to conventional activated sludge, while the granular stability maintains >85% biomass retention under hydraulic shocks; (3) AI-driven optimization—machine learning models enable real-time prediction of nutrient removal efficiency (±5% error) by correlating microbial composition (e.g., Nitrosomonas abundance) with operational parameters (DO: 2–4 mg/L, pH: 7.5–8.5). This review further identifies EPS-mediated microbial co-aggregation and Chlorella–Pseudomonas cross-feeding as pivotal for system resilience. These advances position ABGS as a sustainable solution for low-carbon wastewater treatment, although challenges persist in scaling photobioreactors and maintaining symbiosis under fluctuating industrial loads. Full article

To address the disposal challenges of waste SCR catalysts and the urgent need for sustainable solutions in heavy metal pollution control, this study proposes a green resource utilization strategy based on the sub-molten salt method to convert waste SCR catalysts into highly efficient lead ion adsorbents. Titanate-based adsorbent materials with a loose porous structure were successfully prepared by optimizing the process parameters (reaction temperature of 160 °C, NaOH concentration of 70%, and reaction time of 2 h). The experiments showed that the adsorption efficiency was as high as 99.65% and the maximum adsorption capacity was 76.08 mg/g under ambient conditions (adsorbent dosage of 1.2 g/L, initial Pb(II) concentration of 100 mg/L, contact time of 60 min, and pH = 4). Kinetic analysis showed that the quasi-second-order kinetic model (R² = 0.9985) could better describe the adsorption process, indicating chemisorption as the dominant mechanism. Characterization analysis confirmed that subsequent to the adsorption process, Pb₃(CO₃)₂(OH)₂ formed on the surface of the adsorbent material is the adsorption product of Pb(II) and C-O through ion exchange and surface complexation. This study transforms waste SCR catalysts into sustainable titanate adsorbents through a low-energy green process, providing an eco-efficient solution for heavy metal wastewater treatment while aligning with circular economy principles and sustainable industrial practices. Full article

Background: This study aims to evaluate the quality of treated wastewater flowing in the Zarqa River to determine its suitability for agricultural use. The assessment is based on physicochemical and biological parameters in accordance with Jordanian standards (JS 893:2021), the CCME water quality index, and the weighted arithmetic water quality index (WAWQI). Additionally, a microbial assessment was conducted to identify the presence of pathogens in the treated wastewater. Methods: A total of 168 water samples were collected from seven different sites along the Zarqa River over a 24-month period. This study focused on microbial assessment and selected parameters from the JS 893:2021, including total dissolved solids (TDSs), biochemical oxygen demand (BOD), dissolved oxygen (DO), chemical oxygen demand (COD), and E. coli levels. Furthermore, data were gathered on additional physicochemical parameters such as pH, mineral content (including Na, Ca, K, Mg, and Cl), salts (HCO₃, SO₄, NO₃, and PO₄), and heavy metals (Fe, Cu, Pb, Mn, and Co). The CCME water quality index and weighted arithmetic WQI scores were calculated to determine the water quality from all seven study sites. Results: In terms of Jordanian standards, Site 1 had the lowest TDS and DO values along with E. coli concentration. Further, in terms of minerals and salts, the maximum concentrations found for the sites are given herewith: Site 2 (K⁺ and NO₃), Site 3 (Cl⁻, Na⁺), Site 5 (Ca, HCO₃), and Site 7 (Mg²⁺, PO₄, and SO₄). In terms of pH, all the study sites had pH values within the acceptable range, i.e., between 6 and 9, for irrigation purposes. The concentrations of certain heavy metals, specifically lead (Pb), manganese (Mn), and cobalt (Co), were observed to be negligible. In contrast, Site 6 exhibited the highest concentration of iron (Fe) (0.0178 mg/L), while Site 5 recorded the maximum concentration of copper (Cu) (0.0210 mg/L) among the study locations. Site 1 demonstrated the most favorable water quality among the seven sites evaluated, whereas Site 6 exhibited the poorest water quality. Overall, the water quality from the majority of the sites was deemed suitable for drainage and for irrigating crops classified under the B category. However, based on the weighted arithmetic water quality index (WQI) values, none of the sites achieved a classification of good or excellent water quality, although the water quality at these sites may still be utilized for irrigation purposes. The current study is the first to report the presence of SARS-CoV-2 in Zarqa River water samples. Conclusions: The current study outcomes are promising and provide knowledgeable insights in terms of water quality parameters, while public health aspects should be considered when planning the WWTPs in parallel to reclaiming the wastewater for irrigation purposes. Full article

Heavy metal cations such as Ag⁺, Pb²⁺, and Hg²⁺ can accumulate in living organisms, posing severe risks to biological systems, including humans. Therefore, removing heavy metal cations from wastewater is crucial before discharging them to the environment. However, trace levels and high-capacity removal of the heavy metals remain a critical challenge. This work demonstrates the synthesis and characterization of [Mo₂S₁₂]²⁻ intercalated cobalt aluminum-layered double hydroxide, CoAl―Mo₂S₁₂―LDH (CoAl―Mo₂S₁₂), and its remarkable sorption properties for heavy metals. This material shows high efficiency for removing over 99.9% of Ag⁺, Cu²⁺, Hg²⁺, and Pb²⁺ from 10 ppm aqueous solutions with a distribution constant, K_d, as high as 10⁷ mL/g. The selectivity order for removing these ions, determined from the mixed ion state experiment, was Pb²⁺ < Cu²⁺ ≪ Hg²⁺ < Ag⁺. This study also suggests that CoAl―Mo₂S₁₂ is not selective for Ni²⁺, Cd²⁺, and Zn²⁺ cations. CoAl―Mo₂S₁₂ is an efficient sorbent for Ag⁺, Cu²⁺, Hg²⁺, and Pb²⁺ ions at pH~12, with the removal performance of both Ag⁺ and Hg²⁺ cations retaining > 99.7% across the pH range of ~2 to 12. Our study also shows that the CoAl―Mo₂S₁₂ is a highly competent silver cation adsorbent exhibiting removal capacity (q_m) as high as ~918 mg/g compared with the reported data. A detailed mechanistic analysis of the post-treated solid samples with Ag⁺, Hg²⁺, and Pb²⁺ reveals the formation of Ag₂S, HgS, and PbMoO₄, respectively, suggesting the precipitation reaction mechanism. Full article

The extensive release of water contaminated with lead (Pb(II)) and antimony (Sb(V)) constitutes a serious threat to the human living environment and public health, necessitating immediate attention. In this study, a novel MnFe@SBA composite was synthesized using the hydrothermal method through the in situ growth of MnFe₂O₄ on SBA-15. The MnFe@SBA exhibits an amorphous structure with a high specific surface area of 405.9 m²/g and pore sizes ranging from 2 to 10 nm. Adsorption experiments demonstrated that MnFe@SBA removed over 99% of Pb(II) and 80% of Sb(V) within 120 min at initial concentrations of 10 mg/L, whereas both MnFe₂O₄ and SBA-15 exhibited poor adsorption capacities. Additionally, the MnFe@SBA displayed excellent tolerance towards coexisting cations, including Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺, Ni²⁺, and Cd²⁺, as well as anions such as Cl⁻, NO₃⁻, CO₃²⁻, and PO₄³⁻. The adsorption behavior of Pb(II) onto MnFe@SBA was satisfactorily described by the pseudo-second-order kinetic model and the Freundlich isotherm, while the adsorption of Sb(V) was well-fitted by the pseudo-second-order kinetic model and the Langmuir isotherm. At 318 K, the maximum adsorption capacities of MnFe@SBA for Pb(II) and Sb(V) were determined to be 329.86 mg/g and 260.40 mg/g, respectively. Mechanistic studies indicated that the adsorption of Pb(II) and Sb(V) onto MnFe@SBA involved two primary steps: electrostatic attraction and complexation. In conclusion, the MnFe@SBA is anticipated to serve as an ideal candidate for efficient removal of Pb(II) and Sb(V) from contaminated water. Full article

Biochar is a potential material for making slow-releasing phosphorus (P) fertilizers for the sake of increasing soil P-use efficiency. The adsorption of phosphorus by pineapple leaf biochar (PB) prepared at different pyrolysis temperatures and its mechanism remain unclear. In order to study the effect of preparation temperature on the structural characteristics of biochar from pineapple leaves and the adsorption of phosphorus by biochar, pineapple leaves were used as raw materials to prepare biochar by restricting oxygen supply at 300 °C, 500 °C, and 700 °C. The structural characteristics and adsorption of phosphorus by pineapple leaf biochar at different temperatures (PB300, PB500, and PB700) were analyzed. The results showed the following: (1) The pore structure of biochar pyrolysis at 300 °C (PB300) did not significantly change, while the surface structure of biochar pyrolysis at 700 °C (PB700) significantly changed, the specific surface area (S_BET) increased by 26.91~37.10 times that observed in PB300 and PB500, and the pore wall became thinner. (2) The number of functional groups (C=O) in PB700 decreased, and the relative content of C-H/-CHO in PB500 and PB700 increased by 4.38 times that observed in PB300. (3) The adsorption of phosphorus by biochar was a multi-molecular layer chemisorption, accompanied by single-molecular-layer physical adsorption and intramolecular diffusion. For PB300, both the physical and chemical processes of the adsorption of PO₄³⁻ by biochar were weakened, and the chemical process was dominated by cationic (Ca²⁺, Mg²⁺, Fe³⁺, and Al³⁺) adsorption at 500 °C. For PB700, the physical adsorption dominated by pore size structure was the main process, and the physicochemical adsorption at 700 °C was significantly stronger than that observed at 300 °C and 500 °C. These results indicate that biochar prepared at 500 °C can save energy in the preparation process and has excellent physical and chemical structure, which can be used as the basic material for further modification and preparation of biochar phosphate fertilizer. Full article

Landfills pollute air, soil, and surface and groundwater worldwide. The present work aims to assess the environmental risks of three landfills in southern Riyadh using GIS, soil quality guidelines, and contamination indices. GIS tools indicated an increase in the area of the landfill sites with time. The concentration of heavy metals (HMs) in the investigated landfills had the following descending order: Fe (11,532 mg/kg) ˃ Al (5405 mg/kg) ˃ Pb (561.7 mg/kg) ˃ Zn (356.8 mg/kg) ˃ Mn (165 mg/kg) ˃ Cr (74.8 mg/kg) ˃ Cu (42.7 mg/kg) ˃ Ni (22.4 mg/kg) ˃ V (21.8 mg/kg) ˃ As (5.16 mg/kg) ˃ Co (4.08 mg/kg). The highest values of Al, As, Co, Ni, Pb, V, and Zn were recorded from Al Kharj road landfill (RL3). However, the average values of all HMs were lower than those from most worldwide soils and backgrounds, except for Zn, Cu, Cr, and Pb. Results of enrichment factor and statistical analysis indicated deficiency to minimal enrichment and geogenic sources for Al, Co, Mn, and V, while those of As, Cr, Pb, Zn, and Cu showed EF ˃ 2, which might be indicative of anthropogenic activities, especially in RL3. Additionally, very high contamination and a high effects range—median were reported in individual samples, especially for Pb, As, and Zn, indicating frequent adverse effects for these HMs. The difference in contamination for the HMs in the studied landfill sites might be attributed to the difference in the magnitude of input for each metal into the landfill site and/or the difference in the removal rate of each metal from it. Full article

Male fertility is strongly affected by the overexpression of free radicals induced by heavy metals. The aim of this study was to evaluate the potential antioxidant, anti-inflammatory, and gonado-protective effects of natural compounds. Biochemical and morphological assays were performed on male albino rats divided into five groups: a control group (water only), a group orally exposed to a metal mixture of Pb-Cd-Hg-As alone and three groups co-administered the metal mixture and an aqueous extract of the Nigerian medicinal plant, Anonychium africanum (Prosopis africana, PA), at three different concentrations (500, 1000, and 1500 mg/kg) for 60 days. The metal mixture induced a significant rise in testicular weight, metal bioaccumulation, oxidative stress, and pro-inflammatory and apoptotic markers, while the semen analysis indicated a lower viability and a decrease in normal sperm count, and plasma reproductive hormones showed a significant variation. Parallel phytochemical investigations showed that PA has bioactive compounds like phlobatannins, flavonoids, polyphenols, tannins, saponins, steroids, and alkaloids, which are protective against oxidative injury in neural tissues. Indeed, the presence of PA co-administered with the metal mixture mitigated the toxic metals’ impact, which was determined by observing the oxido-inflammatory response via nuclear factor erythroid 2-related factor 2, thus boosting male reproductive health. Full article

Dopamine (DA) is an important catecholamine neurotransmitter in the mammalian central nervous system that affects many physiological functions. Hence, a highly sensitive and selective sensing platform is necessary for quantification of DA in the human body. In this study, ternary transition metal tellurides of CoNiTe₂ were successfully synthesized using the hydrothermal method. The proposed CoNiTe₂ nanomaterials were dispersed well in Nafion to form a well-dispersed suspension and, when dropped on a glassy carbon electrode (GCE) as the working electrode (CoNiTe₂/Nafion/GCE) for electrochemical non-enzymatic DA sensing, displayed excellent electrocatalytic activity for dopamine electrooxidation. The morphology and physical/chemical properties of CoNiTe₂ nanomaterials were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In order to obtain the best electrochemical response to DA from the fabricated CoNiTe₂/Nafion/GCE, the experimental conditions of electrochemical sensing, including the CoNiTe₂ loading amounts and pH values of the phosphate buffer solution (PBS), were explored to achieve the best electrochemical sensing performance. Under optimal conditions (2 mg of CoNiTe₂ and pH 6.0 of PBS), the fabricated CoNiTe₂/Nafion/GCE showed excellent electrocatalytic activity of DA electrooxidation. The CoNiTe₂/Nafion/GCE sensing platform demonstrated excellent electrochemical performance owing to the optimal structural and electronic characteristics originating from the synergistic interactions of bimetallic Co and Ni, the low electronegativity of Te atoms, and the unique morphology of the CoNiTe₂ nanorod. It exhibited a wide linear range from 0.05 to 100 μM, a high sensitivity of 1.2880 µA µM⁻¹ cm⁻², and a low limit of detection of 0.0380 µM, as well as acceptable selectivity for DA sensing. Therefore, the proposed CoNiTe₂/Nafion/GCE could be considered a promising electrode material for electrochemical non-enzymatic DA sensing. Full article

Copper is a non-biodegradable heavy metal, and high levels in water bodies cause serious environmental and health issues. Douglas fir biochar has a higher number of carboxylic, phenolic, and lactonic groups, which provide suitable active sites for copper removal. Douglas fir biochar (BC) was modified using 20% solutions of KOH (KOH/BC), H₂SO₄, (H₂SO₄/BC), and Na₂CO₃ (Na₂CO₃/BC). All materials were characterized using SEM, SEM-EDS, FTIR, TGA, XRD, BET, and elemental analysis. These modifications were done to compare the activations of those sites by measuring copper removal efficiencies. KOH/BC, H₂SO₄/BC, and Na₂CO₃/BC materials gave surface areas of 389.3, 326.7, and 367.9 m² g⁻¹, respectively, compared with pristine biochar with a surface area of 578.9 m² g⁻¹. The maximum Langmuir adsorption capacities for Na₂CO₃/BC, KOH/BC, BC, and H₂SO₄/BC were 24.79, 18.31, 17.38, and 9.17 mg g⁻¹, respectively. All three modifications gave faster kinetics at 2 mg/L initial copper concentrations (pH 5) compared with pristine BC. The copper removal efficiency was demonstrated in four different spiked real water matrices. The copper removals of all four water matrices were above 90% at 2 mg/L initial concentration with a 2 g/L biochar dosage. The competitive effects of Pb²⁺, Zn²⁺, Cd²⁺, and Mg²⁺ were studied at equimolar concentrations of Cu²⁺ and competitive ions for all four materials. Full article

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) utilizes angiotensin-converting enzyme 2 (ACE2) as its main receptor for cell entry. We bioengineered a soluble ACE2 protein termed ACE2 618-DDC-ABD that has increased binding to SARS-CoV-2 and prolonged duration of action. Here, we investigated the protective effect of this protein when administered intranasally to k18-hACE2 mice infected with the aggressive SARS-CoV-2 Delta variant. k18-hACE2 mice were infected with the SARS-CoV-2 Delta variant by inoculation of a lethal dose (2 × 10⁴ PFU). ACE2 618-DDC-ABD (10 mg/kg) or PBS was administered intranasally six hours prior and 24 and 48 h post-viral inoculation. All animals in the PBS control group succumbed to the disease on day seven post-infection (0% survival), whereas, in contrast, there was only one casualty in the group that received ACE2 618-DDC-ABD (90% survival). Mice in the ACE2 618-DDC-ABD group had minimal disease as assessed using a clinical score and stable weight, and both brain and lung viral titers were markedly reduced. These findings demonstrate the efficacy of a bioengineered soluble ACE2 decoy with an extended duration of action in protecting against the aggressive Delta SARS-CoV-2 variant. Together with previous work, these findings underline the universal protective potential against current and future emerging SARS-CoV-2 variants. Full article

The Late Paleozoic tectonic evolution of the Xing’an block in the eastern Central Asian orogenic belt has long been the subject of debate. In this paper, a comprehensive study of U-Pb zircon ages, Lu-Hf isotopes and whole-rock elemental analyses was carried out on Hadayang schists. Representative samples of the epidote-biotite-albite schist and biotite-albite schist yielded the weighted mean ²⁰⁶Pb/²³⁸U ages of 360 ± 2 Ma and 355 ± 3 Ma, respectively. This indicated the presence of Late Devonian–Early Carboniferous intermediate-basic rocks in the eastern Xing’an block. The Hadayang schists exhibited a Na-rich, tholeiitic and calc-alkaline affinity in composition with low Mg# (35.2–53.0), Cr (23.7–86.5 ppm), Ni (21.1–40.0 ppm) and Co (12.1–30.6 ppm). They were characterized by enrichment of LILEs, depletion of HFSEs and highly positive zircon ε_Hf(t) values (the average values were +8.93 and +9.29, respectively). The magma source of the Hadayang schists was a mantle that consisted of both spinel and garnet lherzolite, with a partial melting degree of 1%–5%, and it had undergone fractional crystallization of olivine, orthopyroxene and plagioclase. The Hadayang schists, together with other Late Devonian–Early Carboniferous intermediate-basic magmatic rocks in the eastern Xing’an block, were formed in an intracontinental extension tectonic setting similar to that of the North American Basin and Range basalt. Moreover, Late Devonian–Early Carboniferous ophiolite under a similar tectonic background in the western Xing’an block has been reported. We believe that the Xing’an block would have been in the stage of intracontinental extension during the Late Devonian–Early Carboniferous. Full article

The primary objective of this study was to determine the heavy metal contents in the water–soil–coriander samples in an industrial wastewater irrigated area and to assess the health risks of these metals to consumers. Sampling was done from areas adjoining the Chistian sugar mill district Sargodha and two separate sites irrigated with groundwater (Site 1), and sugar mill effluents (Site 2) were checked for possible metal contamination. The water–soil–coriander continuum was tested for the presence of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Ni), lead (Pb), and zinc (Zn). The mean concentrations of all metals were higher than the permissible limits for all studied metals except for Mn in the sugar mill wastewater, with Fe (8.861 mg/L) and Zn (9.761 mg/L) exhibiting the highest values. The mean levels of Fe (4.023 mg/kg), Cd (2.101 mg/kg), Cr (2.135 mg/kg), Cu (2.180 mg/kg), and Ni (1.523 mg/kg) were high in the soil at Site 2 in comparison to the groundwater irrigated site where Fe (3.232 mg/kg) and Cd (1.845 mg/kg) manifested high elemental levels. For coriander specimens, only Cd had a higher mean level in both the groundwater (1.245 mg/kg) and the sugar mill wastewater (1.245 mg/kg) irrigated sites. An estimation of the pollution indices yielded a high risk from Cd (health risk index (HRI): 173.2), Zn (HRI: 7.012), Mn (HRI: 6.276), Fe (HRI: 1.709), Cu (HRI: 1.282), and Ni (HRI: 1.009), as all values are above 1.0 indicating a hazard to human health from consuming coriander irrigated with wastewater. Regular monitoring of vegetables irrigated with wastewater is strongly advised to reduce health hazards to people. Full article

Focal cerebral ischemia (fCI) can result in brain injury and sensorimotor deficits. Brown algae are currently garnering scientific attention as potential therapeutic candidates for fCI. This study investigated the therapeutic effects of the hot water extract of Petalonia binghamiae (wPB), a brown alga, in in vitro and in vivo models of fCI. The neuroprotective efficacy of wPB was evaluated in an in vitro excitotoxicity model established using HT-22 cells challenged with glutamate. Afterward, C57/BL6 mice were administered wPB for 7 days (10 or 100 mg/kg, intragastric) and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) operation, which was used as an in vivo fCI model. wPB co-incubation significantly inhibited cell death, oxidative stress, and apoptosis, as well as stimulated the expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, and the nuclear translocation of its upstream regulator, nuclear factor erythroid 2-related factor 2 (Nrf2) in HT-22 cells challenged with glutamate-induced excitotoxicity. Pretreatment with either dose of wPB significantly attenuated infarction volume, neuronal death, and sensorimotor deficits in an in vivo fCI model. Furthermore, the attenuation of oxidative stress and apoptosis in the ischemic lesion accompanied the wPB-associated protection. This study suggests that wPB can counteract fCI via an antioxidative effect, upregulating the Nrf2/HO-1 pathway. Full article