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2,233 result(s) for "Trace levels"
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Development and validation of an ICP-MS method and its application in assessing heavy metals in whole blood samples among occupationally exposed lead smelting plant workers
Occupational exposure to heavy metals affects various organ systems and poses a significant health risk to workers. Consequently, its precise estimation is of clinical concern and warrants the need for an analytical method with reliable precision and accuracy. The current study aimed to develop an analytical method using inductively coupled plasma‒mass spectrometry (ICP-MS) to detect trace to elevated levels of potentially toxic elements in human blood. The sample preparation was optimized using a two-step ramp temperature microwave acid digestion program. The toxic elements were quantified using ICP-MS operating in kinetic energy discrimination (KED) mode, adjusting the data acquisition parameters and instrumental settings. The analytical method was validated using standard performance parameters. Each validation parameter was aligned with the acceptable criteria outlined in standard guidelines. The method achieved optimal linearity ( r 2  > 0.99), recovery (85.60–112.00%), and precision (1.35–7.03%), was capable of detecting the lowest concentrations of 0.32, 0.28, 0.28, and 0.19 µg/L, and was capable of quantifying trace levels of 1.01, 0.88, 0.90, and 0.62 µg/L for arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb), respectively. Post-validation, the method was applied to estimate heavy metals in blood samples from 250 Pb-smelting plant workers, revealing potential health implications of occupational exposure. The cohort analysis revealed that demographic and employment factors were associated with elevated blood Pb levels, leading to symptoms and health risks. Clinical analysis revealed that 33.6% of the participants experienced hypertension. These findings highlight the significant health risks associated with elevated blood Pb levels. The weak but significant correlation with systolic blood pressure underscores the need for improved monitoring and workplace safety. This emphasizes the importance of continuous monitoring, targeted interventions, and enhanced occupational hygiene to protect workers’ well-being. Graphical abstract
Removal of heavy metal ions from aqueous system by ion-exchange and biosorption methods
Pollution due to heavy metals is currently a serious problems affecting water bodies. The removal of heavy metals is of great concern due to their toxicity at trace levels and accumulation in the biosystem. Here we review the technical feasibility of biosorption and ion exchange methods for the removal of various heavy metals from the aqueous media. Chemical pretreatment of low-cost biosorbents are presented. Chemically modified biosorbents exhibit far better adsorption capacities than unmodified ones. We also highlighted the effect of pH on the biosorption for maximal uptake of heavy metals, because pH modifies the surface charge of the biosorbent as well as the speciation of heavy metals.
Trace removal of benzene vapour using double-walled metal–dipyrazolate frameworks
In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate–sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal–dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47–3.28 mmol g −1 at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal–organic framework Co(BDP) (H 2 BDP = 1,4-di(1 H -pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (C 6 H 6 @BUT-55) and density functional theory calculations, which reveal that C–H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures. Volatile organic compounds such as benzene are toxic pollutants that cause health issues even at trace concentrations. Here, a double-walled metal–organic framework is presented that demonstrates high uptake at very low pressures (<10 Pa), allowing the removal of benzene to below acceptable indoor limits.
Conventional and non-conventional adsorbents for wastewater treatment
The removal of contaminants from wastewaters is a major challenge in the field of water pollution. Among numerous techniques available for contaminant removal, adsorption using solid materials, named adsorbents, is a simple, useful and effective process. The adsorbent matter can be mineral, organic or biological. Activated carbon is the preferred, conventional material at the industrial scale. Activated carbon is extensively used not only for removing pollutants from wastewater streams, but also for adsorbing contaminants from drinking water sources, e.g., groundwater, rivers, lakes and reservoirs. However, the widespread use of activated carbon is restricted due to a high cost. In the last three decades, numerous approaches using non-conventional adsorbents have been studied for the development of cheaper and more effective adsorbents to eliminate pollutants at trace levels. This review gives an overview of liquid–solid adsorption processes using conventional and non-conventional adsorbents for pollutant removal. The manuscript outlines the principles of adsorption and proposes a classification for adsorbent materials. Finally, the various mechanisms involved in the adsorption phenomena are discussed.
Water-stable porous Al24 Archimedean solids for removal of trace iodine
In this paper, we report a unique type of core-shell crystalline material that combines an inorganic zeolitic cage structure with a macrocyclic host arrangement and that can remove trace levels of iodine from water effectively. These unique assemblies are made up of an inorganic Archimedean truncatedhexahedron ( tcu ) polyhedron in the kernel which possesses six calixarene-like shell cavities. The cages have good adaptability to guests and can be assembled into a series of supramolecular structures in the crystalline state with different lattice pore shapes. Due to the unique core-shell porous structures, the compounds are not only stable in organic solvents but also in water. The characteristics of the cages enable rapid iodine capture from low concentration aqueous I 2 /KI solutions (down to 4 ppm concentration). We have studied the detailed process and mechanism of iodine capture and aggregation at the molecular level. The facile synthesis, considerable adsorption capacity, recyclability, and β- and γ-radiation resistance of the cages should make these materials suitable for the extraction of iodine from aqueous effluent streams (most obviously, radioactive iodide produced by atomic power generation). The removal of radioactive elements is important to human health and sustainable development. Here, the authors reveal the synthesis of water-stable Archimedean solids based on the earth-abundant element for the fast removal of trace iodine.
Biostimulant Properties of Seaweed Extracts in Plants: Implications towards Sustainable Crop Production
The use of seaweed-based bioproducts has been gaining momentum in crop production systems owing to their unique bioactive components and effects. They have phytostimulatory properties that result in increased plant growth and yield parameters in several important crop plants. They have phytoelicitor activity as their components evoke defense responses in plants that contribute to resistance to several pests, diseases, and abiotic stresses including drought, salinity, and cold. This is often linked to the upregulation of important defense-related genes and pathways in the plant system, priming the plant defenses against future attacks. They also evoke phytohormonal responses due to their specific components and interaction with plant growth regulation. Treatment by seaweed extracts and products also causes significant changes in the microbiome components of soil and plant in support of sustainable plant growth. Seaweed extracts contain a plethora of substances which are mostly organic, but trace levels of inorganic nutrient elements are also present. Fractionation of seaweed extracts into their components and their respective bioassays, however, has not yielded favorable growth effects. Only the whole seaweed extracts have been consistently proven to be very effective, which highlights the role of multiple components and their complex interactive effects on plant growth processes. Since seaweed extracts are highly organic, they are ideally suited for organic farming and environmentally sensitive crop production. They are also very compatible with other crop inputs, paving the way for an integrated management approach geared towards sustainability. The current review discusses the growth and functional effects evoked by seaweed extracts and their modes and mechanisms of action in crop plants which are responsible for elicitor and phytostimulatory activities. The review further analyses the potential value of seaweed extracts in integrated crop management systems towards sustainable crop production.
Synthesis, characterization and heavy metal removal efficiency of nickel ferrite nanoparticles (NFN’s)
The heavy metals, such as Cr(VI), Pb(II) and Cd(II), in aqueous solutions are toxic even at trace levels and have caused adverse health impacts on human beings. Hence the removal of these heavy metals from the aqueous environment is important to protect biodiversity, hydrosphere ecosystems, and human beings. In this study, magnetic Nickel-Ferrite Nanoparticles (NFNs) were synthesized by co-precipitation method and characterized using X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Field Emission Scanning Electronic Microscopy (FE-SEM) techniques in order to confirm the crystalline structure, composition and morphology of the NFN’s, these were then used as adsorbent for the removal of Cr(VI), Pb(II) and Cd(II) from wastewater. The adsorption parameters under study were pH, dose and contact time. The values for optimum removal through batch-adsorption were investigated at different parameters (pH 3–7, dose: 10, 20, 30, 40 and 50 mg and contact time: 30, 60, 90, and 120 min). Removal efficiencies of Cr(VI), Pb(II) and Cd(II) were obtained 89%, 79% and 87% respectively under optimal conditions. It was found that the kinetics followed the pseudo second order model for the removal of heavy metals using Nickel ferrite nanoparticles.
Efficacy of dietary odd-chain saturated fatty acid pentadecanoic acid parallels broad associated health benefits in humans: could it be essential?
Dietary odd-chain saturated fatty acids (OCFAs) are present in trace levels in dairy fat and some fish and plants. Higher circulating concentrations of OCFAs, pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0), are associated with lower risks of cardiometabolic diseases, and higher dietary intake of OCFAs is associated with lower mortality. Population-wide circulating OCFA levels, however, have been declining over recent years. Here, we show C15:0 as an active dietary fatty acid that attenuates inflammation, anemia, dyslipidemia, and fibrosis in vivo , potentially by binding to key metabolic regulators and repairing mitochondrial function. This is the first demonstration of C15:0’s direct role in attenuating multiple comorbidities using relevant physiological mechanisms at established circulating concentrations. Pairing our findings with evidence that (1) C15:0 is not readily made endogenously, (2) lower C15:0 dietary intake and blood concentrations are associated with higher mortality and a poorer physiological state, and (3) C15:0 has demonstrated activities and efficacy that parallel associated health benefits in humans, we propose C15:0 as a potential essential fatty acid. Further studies are needed to evaluate the potential impact of decades of reduced intake of OCFA-containing foods as contributors to C15:0 deficiencies and susceptibilities to chronic disease.
Photo-induced enhanced Raman spectroscopy for universal ultra-trace detection of explosives, pollutants and biomolecules
Surface-enhanced Raman spectroscopy is one of the most sensitive spectroscopic techniques available, with single-molecule detection possible on a range of noble-metal substrates. It is widely used to detect molecules that have a strong Raman response at very low concentrations. Here we present photo-induced-enhanced Raman spectroscopy, where the combination of plasmonic nanoparticles with a photo-activated substrate gives rise to large signal enhancement (an order of magnitude) for a wide range of small molecules, even those with a typically low Raman cross-section. We show that the induced chemical enhancement is due to increased electron density at the noble-metal nanoparticles, and demonstrate the universality of this system with explosives, biomolecules and organic dyes, at trace levels. Our substrates are also easy to fabricate, self-cleaning and reusable. Surface enhanced Raman spectroscopy is a sensitive technique capable of detecting single molecules via their vibrational fingerprints. Here, the authors demonstrate improved sensitivity with photo-induced enhanced Raman spectroscopy applied to trace-level detection of explosives and other analytes.
D-mannose suppresses macrophage IL-1β production
D-mannose is a monosaccharide approximately a hundred times less abundant than glucose in human blood. Previous studies demonstrated that supraphysiological levels of D-mannose inhibit tumour growth and stimulate regulatory T cell differentiation. It is not known whether D-mannose metabolism affects the function of non-proliferative cells, such as inflammatory macrophages. Here, we show that D-mannose suppresses LPS-induced macrophage activation by impairing IL-1β production. In vivo, mannose administration improves survival in a mouse model of LPS-induced endotoxemia as well as decreases progression in a mouse model of DSS-induced colitis. Phosphomannose isomerase controls response of LPS-activated macrophages to D-mannose, which impairs glucose metabolism by raising intracellular mannose-6-phosphate levels. Such alterations result in the suppression of succinate-mediated HIF-1α activation, imposing a consequent reduction of LPS-induced Il1b expression. Disclosing an unrecognized metabolic hijack of macrophage activation, our study points towards safe D-mannose utilization as an effective intervention against inflammatory conditions. Mannose is present at trace levels in blood and regulates cancer growth. Here the authors show that supraphysiological levels of mannose can also regulate macrophages, limiting their production of IL-1β and increasing resistance of mice to LPS-induced endotoxemia and DSS-induced colitis.