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A novel nanoparticle (NPs) iron oxyhydroxide modified with rice husk (RH + FeOOH) was synthesized with wet chemical method. Batch study was performed to investigate fluoride removal and adsorption capacity. The RH + FeOOH NPs were characterized by using Fourier transform infrared spectroscopy, X-ray powder diffraction, Brunauer–Emmett–Teller, scanning electron microscope with energy dispersion, transmission electron microscope, and particle size analyzer. By varying parameters, batch adsorption with adsorption capacity was performed such as contact time, stirring rate, adsorbent dosage, temperature, initial concentration, and pH. The BET surface area and the pore volume of the FeOOH and RH + FeOOH were found to be 157 m² g⁻¹, 195 m² g⁻¹ and 0.136 m² g⁻¹, 0.224 m² g⁻¹. Based on kinetic study, pseudo-second-order was followed by regression coefficient (R²) 0.99. Langmuir isotherm model showed the best adsorption capacity of 26 mg g⁻¹. Moreover, the RH + FeOOH showed best affinity towards fluoride removal and may act as an excellent adsorbent for fluoride treatment from aqueous solution. Synthesis and Fluoride Adsorption Mechanism of Iron Oxyhydroxide Modified with rice husk

The fungicide carbendazim is an ecotoxic pollutant frequently found in water reservoirs. The ability of microorganisms to remove pollutants found in diverse environments, soil, water, or air is well documented. Although microbial communities have many advantages in bioremediation processes, in many cases, those with the desired capabilities may be slow-growing or have low pollutant degradation rates. In these cases, the manipulation of the microbial community through enrichment with specialized microbial strains showing high specific growth rates and high rates and efficiencies of pollutant degradation is desirable. In this work, bacteria of the genera Klebsiella, Flavobacterium, and Stenotrophomonas, isolated from the biofilm attached to the packed zones of a biofilm reactor, were able to grow individually in selective medium containing carbendazim. In the three bacteria studied, the mheI gene encoding the first enzyme involved in the degradation of the fungicide carbendazim was found. Studying the dynamics of growth and carbendazim degradation of the three bacteria, the effect of co-formulants was also evaluated. The pure compound and a commercial formulation of carbendazim were used as substrates. Finally, the study made it possible to define the biokinetic advantages of these strains for amendment of microbial communities.

Functional trace elements and vitamins can boost immunity and antioxidative response in aquatic animals without creating environmental hazards. While nano-selenium (Nano-Se) and vitamin C (VC) have been used as immunomodulators and antioxidants in animal and poultry feed, there is little data on Nano-Se and/or VC supplementation in aquatic animals. Thus, the current study evaluated the impact of adding Nano-Se and VC to the diets of Nile tilapia for 8 weeks. Four diets were formulated and offered to the fish: no supplementation (control), 1 mg Nano-Se/kg, 500 mg VC/kg, and 1 mg Nano-Se + 500 mg VC/kg of food. Growth-related parameters (final body weight, weight gain, and specific growth rate) were significantly increased in tilapia fed Nano-Se and VC, with a reduced feed conversion ratio (P < 0.05). Intestinal villus length and width as well as the number of goblet cells were increased in tilapia fed Nano-Se and/or VC (P < 0.05). Additionally, dietary Nano-Se and/or VC significantly increased nitro-blue tetrazolium (NBT) level, superoxide dismutase, glutathione peroxidase, catalase, the phagocytic index, and lysozyme and phagocytic activities (P < 0.05). However, significantly reduced levels of malonaldehyde were observed in fish fed Nano-Se and/or VC (P < 0.05). TNF-α and IL-1β gene expressions in the liver and spleen of the fish were significantly upregulated by Nano-Se and/or VC (P < 0.05). The results revealed the potential role of Nano-Se and/or VC in enhancing growth, intestinal morphometry, and immune and antioxidative responses in Nile tilapia.

In this study, Kola nut extract (KE) was evaluated for inhibiting ability towards low carbon steel corrosion in 1 M HCl solution using weight loss and electrochemical techniques. The surface of the corroded carbon steel was examined by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Elemental composition of the corrosion products and/or adsorbed inhibitor film on the carbon steel surface was determined with the aid of an energy-dispersive X-ray spectroscopy (EDX). The ultraviolet-visible (UV-vis) experiments were also performed to get information about the interaction of KE with the carbon steel surface. It was found that KE exhibited good corrosion protection property. From weight loss technique, corrosion rate was reduced from 0.387 to 0.054 mm/year by 700 ppm of KE at room temperature after 24 h immersion and this corresponded to inhibition efficiency (IE) of 86%. The IE however depreciated with rise in temperature. FTIR results reveal that KE interacted with the carbon steel surface through the O and N heteroatoms of its phytoconstituents. FTIR spectroscopy, UV-vis, SEM, AFM, and EDX data provided proof of KE adsorption on the steel surface as reason for the corrosion inhibition.

The indigenous population is one of the most vulnerable to suffer from contaminated environments. One of the target organs to suffer early deterioration from exposure to toxins is the kidney. The objective of this article was to evaluate biomarkers of exposure to organic and inorganic toxins and biomarkers of early kidney damage in urine from an indigenous Tenek population in Mexico. The biomarkers of exposure were Li, Be, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, Sn, Ba, and Pb evaluated by ICP-MS and hippuric acid for toluene exposure evaluated by UV-coupled with liquid chromatography; the biomarkers of kidney damage were cystatin C (Cys-C), osteopontin (OPN), retinol-binding protein-4 (RPB-4), and neutrophil gelatinase-associated lipocalin (NGAL). Thirty-one urine samples were obtained from indigenous people; 16, 42, 45.1, and 45.2% of the population exceeded the reference values for Pb, Zn, As, and hippuric acid respectively. Our results demonstrate significant correlations between the metals tested and the proteins associated with renal damage; Cys-C, OPN, and RPB4 showed a significant correlation with Li, B, and Mo, as well as hippuric acid in the case of Cys-C and Zn in OPN and RPB-4; NGAL did not present significant correlations with any of the pollutants of the study. This pilot study contributes to the evidence of great inequity in health associated to environmental pollution matters faced by indigenous people and addresses the need of initiatives for mitigation under the perspective that health is a fundamental human right.

In the African continent, several studies have been conducted to determine PAH pollution levels with their associated health risks in the environment. However, these studies are very much disconnected. The objective of this study is to conduct a systematic review that serves as a comprehensive report on the PAH-related studies conducted in the African continent. Data sources are from Google Scholar and PubMed. English language studies that reported on PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items were selected. Specific PAHs included the following: 33 PAHs comprising of the 16 USEPA PAHs, non-alkylated PAHs, non-alkylated PAHs, oxygenated PAHs (OPAHs), and azaarenes (AZAs). Study appraisal and synthesis methods: The Newcastle–Ottawa Scale (NOS) was adapted to assess the quality of the selected studies basing on their sampling methods, analytical techniques, and results. A total of 121 studies were reviewed, with the majority (56) being from Nigeria. PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items recorded total concentrations of PAHs ranging from 5 to 3585 μg/kg, BDL to 6,950,000 μg/kg, 0 to 10,469,000 μg/kg, 0 to 7.82 ± 0.85 μg/m³, and 2.5 to 7889 ± 730 μg/kg respectively. Carcinogenic risk assessment for children and adults ranged from very low to very high levels when compared to the ILCR range (10⁻⁶ to 10⁻⁴) defined by the USEPA. Out of 54 African countries, only 19 were represented. The majority of selected studies failed to apply any standard protocols for sample collection and analysis. The low to very high PAH levels reported in studies calls for effective actions on environmental health. Similar systematic reviews are expected to be performed in other continents for a global assessment of PAH pollution.

Heterogeneous catalysis is promising for water treatment. Solid catalysts play governing roles. Herein, the surface-disordered WO₃, D-WO₃, engineered with surface and sub-surface defective sites from NaBH₄ reduction was proven to be an effective catalyst for H₂O₂ activation. The defective degree and defects amount on WO₃ were regulated by NaBH₄. More than 95% of two typical azo dyes, RhB and MG, were selectively degraded in D-WO₃/H₂O₂ system during 3.0 h, while no significant activity was observed for MO as well as bisphenol A, roxarsone, phenol, 4-chlorophenol, p-nitrophenol, o-aminophenol, urea, and 2,4-dichlorophenol in comparison under the identical conditions (mainly less than 20%). Both ESR and radical scavenging tests indicated the minor role of ·OH from H₂O₂ activation on D-WO₃. The superior activity of D-WO₃ could be mainly attributed to the surface and sub-surface defects with finely tailored local atomic configurations and electronic structures of central metal sites. Surface and sub-surface defective sites could serve as the reactive sites of interfacial adsorption, dissociative activation, and catalytic decomposition for both oxidant and pollutants, with high adsorption energy, strong structural activation, and superior catalytic activity. Our findings provided a new chance for non-selective radical catalysis based on transition metal oxides and a promising catalyst with high performance, low cost, and no toxicity for pollutant degradation with weak matrix effects in wastewater and surface water.

Iron mining residue was evaluated as a potential catalyst for heterogeneous Fenton/photo-Fenton degradation of sulfonamide antibiotics. The residue contained 25% Fe₂O₃ and 8% CeO₂, as determined by X-ray fluorescence spectroscopy, as well as other minor phases such as P₂O₅, SiO₂, and TiO₂. X-ray photoelectron spectroscopy analysis revealed a lower content of iron oxides on the surface, which restricted interaction of the residue with H₂O₂. Despite this limitation and the relatively low specific surface area (26 m² g⁻¹) of the crude iron mining residue (without any pretreatment), the material presented high catalytic activity for Fenton degradation of sulfonamide antibiotics. The degradation was strongly dependent on the initial pH, showing the highest efficiency at pH 2.5. For this condition, a concentration of sulfathiazole below the detection limit was obtained within 30 min, under black light irradiation and using 0.3 g L⁻¹ residue, with low H₂O₂ consumption (0.2 mmol L⁻¹). The residue also provided highly efficient sulfathiazole degradation in the dark, with the concentration of the antibiotic decreasing to an undetectable level after 45 min. Simultaneous degradation of two sulfonamide antibiotics revealed higher recalcitrance of sulfamethazine, compared to sulfathiazole, but the levels of both antibiotics decreased to below the detection limit after 45 min. The residue was very stable, since no significant concentration of soluble iron was detected after the degradation process. Furthermore, high catalytic activity was maintained during up to five cycles, showing the potential of this material for use as a low-cost and environmentally compliant catalyst in Fenton processes.

Nanoparticles (NPs) are very small particles present in a wide range of materials. There is a dearth of knowledge regarding their potential secondary effects on the health of living organisms and the environment. Increasing research attention, however, has been directed toward determining the effects on humans exposed to NPs in the environment. Although the majority of studies focus on adult animals or populations, embryos of various species are considered more susceptible to environmental effects and pollutants. Hence, research studies dealing mainly with the impacts of NPs on embryogenesis have emerged recently, as this has become a major concern. Chicken embryos occupy a special place among animal models used in toxicity and developmental investigations and have also contributed significantly to the fields of genetics, virology, immunology, cell biology, and cancer. Their rapid development and easy accessibility for experimental observance and manipulation are just a few of the advantages that have made them the vertebrate model of choice for more than two millennia. The early stages of chicken embryogenesis, which are characterized by rapid embryonic growth, provide a sensitive model for studying the possible toxic effects on organ development, body weight, and oxidative stress. The objective of this review was to evaluate the toxicity of various types of carbon black nanomaterials administered at the beginning of embryogenesis in a chicken embryo model. In addition, the effects of diamond and graphene NPs and carbon nanotubes are reviewed.