Trace Metals Research Articles

Pilot-Scale Production of Sericin-Derived Oligopeptides (SDOs) from Yellow Silk Cocoons: Peptide Characterization and Specifications

Our previous research demonstrated the health benefits of sericin-derived oligopeptides (SDOs) from yellow silk cocoons, particularly their hypoglycemic and antihypertensive properties. This study aims to produce SDOs at a pilot scale, preparing them for large commercial production as a novel food ingredient, and investigates the impact of scale-up on their characteristics and specifications. We compared the productivity of SDOs generated from 25 L and 300 L batches via the hydrolysis of sericin using 5% Neutrase (E/S) at 50 °C for 4 h. The 300 L production scale outperformed the 25 L scale, achieving a hydrolysis degree (DH) of 8.63%, a solid recovery rate of 94.35%, and enhanced inhibitory actions for dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE). The characterization of peptides was carried out in ultrafiltered SDOs. Peptides < 3 kDa demonstrated optimal enzyme inhibition and were then fractionated by size exclusion chromatography into nine distinct fractions. Of the nine fractions, F1, F8, and F9 had significant enzyme inhibitory activity. LC-MS/MS analysis revealed 32 unique peptide sequences, with YPDLPYH exhibiting significant dual inhibitory effects on both DPP-IV (IC50 1.35 mM) and ACE (IC50 18.10 μM). The maximum residue limit (MRL) for trace metals, pesticide residues, and microbiological contamination in SDOs complies with food regulations. SDOs exhibited stability at 4, 25, and 45 °C for six months, based on their physical characteristics and biological activity. Considering their investigated characteristics, SDOs could be manufactured at a pilot capacity and used as a functional food component in commercial applications designed to improve metabolic health.

The Plant Growth-Promoting Ability of Alfalfa Rhizobial Strains Under Nickel Stress

The growth and nutrient balance of legumes can be disrupted in soils with increased nickel (Ni) concentrations. The inoculation of legumes with rhizobia, symbiotic nitrogen-fixing bacteria, can be used for the alleviation of trace metal stress in plants. This study evaluated the Ni tolerance of alfalfa rhizobia isolates and some plant growth-promoting traits in the presence of Ni: indole-3-acetic acid (IAA) production, Ni biosorption potential, and the effect of rhizobia on alfalfa (Medicago sativa L.) growth. The strains were characterized as Shinorhizobium meliloti, Sinorhizobium medicae, and Rhizobium tibeticum. In total, 70% of the tested strains tolerate up to 0.8 mM Ni, while 15% of the strains tolerate 1.2 mM Ni. The production of IAA was maintained in the presence of Ni until bacterial growth was stopped by raising the Ni concentration. Alfalfa seed germination is significantly reduced in the presence of 0.5 mM Ni, while a significant reduction in 10-day-old seedling length already occurs at a Ni concentration of 0.03 mM. In the plant experiment, when alfalfa was inoculated with rhizobial strains, nodulation was maintained up to 0.05 mM Ni, but a significant reduction in nodule number was detected at 0.01 mM Ni. At the concentration of 0.005 mM Ni, inoculation with 12 particular rhizobial strains significantly improved the number of nodules per plant, plant height, and root length, as well as plant shoot dry weight, compared to non-inoculated plants with Ni addition. However, higher concentrations caused a reduction in all of these plant growth parameters compared to the plants without Ni. The selected rhizobia strains showed a Ni biosorption capacity of 20% in the in vitro assay. The inoculation of alfalfa with effective rhizobial strains improves growth parameters compared to non-inoculated plants in the presence of certain concentrations of Ni.

Trace metal in soils of auto-mechanics workshops in Akure metropolis, Nigeria: assessment of environmental quality

Trace metal in soils of auto-mechanics workshops in Akure metropolis, Nigeria: assessment of environmental quality

Analysis of Volatile Organic Compounds in Textiles: Insights from GC–MS with Metal Content Assessment Using ICP-MS

This study primarily focuses on the analysis of volatile organic compounds using GC–MS, with ICP-MS employed as a complementary method to quantify trace metal content. Headspace GC–MS was conducted to detect alkylphenol ethoxylates (APEOs), formaldehyde, aromatic amines derived from azo dyes, perfluorinated carboxylic acids, chlorophenols (PCPs), tetrachlorophenols (TPCs), and phthalates in textile samples of different origin and composition. Principal component analysis was used to detect patterns in the volatilome according to the origin and the textile composition. In addition, seven metals (Cr, Ni, Cu, Mo, Cd, Hg, and Pb) were quantified in a subset of samples. The study revealed distinct chemical profiles in textiles based on their origin, with GC–MS identifying key volatile organic compounds and ICP-MS quantifying heavy metals in a subset of samples. Principal component analysis highlighted cotton content as a critical factor in differentiating textile profiles. While most samples adhered to regulatory standards, some exceeded thresholds for metals like copper and nickel, underscoring the need for enhanced quality control in manufacturing processes. By integrating advanced analytical methods, this study provides insights into sustainable and safe textile production, offering valuable benchmarks for regulatory compliance and industry best practices. The outcomes contribute to improving product safety, promoting responsible manufacturing, and supporting regulatory bodies in the enforcement of environmental and safety standards, aligning with the growing demand for sustainability in the textile sector.

Phase Equilibria and Trace Element Deportments in Fe–O–Al2O3–SiO2 Slags and Molten Copper Matte at 1473 K (1200 °C), Fixed p(O2) and p(SO2), and Silica/Magnetite Saturation

Abstract Understanding the role of major components of electric waste during smelting of these materials to recover valuable trace metals is poorly constrained by experimental data. In this study, phase equilibria and trace element deportments were studied at 1473 K (1200 °C) in conditions of combined sulfide concentrate and electric and electronic equipment waste processing in batchwise submerged lance smelting. In this system, liquid slag domain is limited by silica and magnetite saturation boundaries or primary phase fields at all alumina concentrations from alumina-free slags to silica-spinel double saturation. The impact of alumina concentration in slag at fixed oxygen and sulfur dioxide partial pressures on the distributions of Ag, Cu, In, Pb, and Sn was studied. Elemental concentrations in slag, matte, and solid magnetite (a Fe–Al spinel solid solution) were measured using electron probe microanalysis and laser ablation-ICP-mass spectrometry techniques. The observed impact of alumina on the distribution coefficient of silver, copper, and indium favored the matte phase at silica and magnetite saturation but lead and tin behaved differently within different primary phase fields as a function of alumina concentration.

Trace metals induce microbial risk and antimicrobial resistance in biofilm in drinking water

This study investigated the changes in water quality and microbial risks resulting from trace metal pollutants in stagnant drinking water conditions using a 168-h experimental simulation and a metagenomic approach. The results showed that Fe(III) increased the water turbidity. Stagnation also caused significant biofilm growth, which was increased by trace metal pollutants, resulting in a higher production of extracellular polymeric substances (EPS). Adaptive mechanisms of bacterial communities dominated by Pseudomonadota in response to trace metal pollutant stress were discovered. Pathogenic bacteria, particularly Salmonella enterica and Pseudomonas aeruginosa, were found in stagnant drinking water, potentially exacerbated by Al(III). The overall exposure risk of antibiotic resistance genes (ARGs) increased, whereas Fe(III) enhanced the co-occurrence of ARGs and pathogens, potentially leading to serious hidden microbial risks. This study reveals imperceptible microbial risks posed by trace metal pollutants in stagnant drinking water, providing scientific warning and advice for drinking water safety.

Toxicity Assessment of River Sediments Impacted by Open-Pit Coal Mining in Colombia Using Caenorhabditis elegans

Coal mining is a critical economic for Colombia. However, mineral extraction is usually carried out near rivers that provide ecosystem services to riverside populations. Cesar River receives discharges from several open-pit coal mines, as well as from other anthropogenic sources. The aim of this work was to assess the chemical and the toxicity profile of the sediments from this river. Bottom sediment samples were collected from 12 points along the river, including tributaries and a Ramsar site, the Zapatosa Marsh. Trace elements were quantified employing ICP-MS, and mercury (Hg) was measured using a direct Hg analyzer. Aqueous extracts (K-medium) were obtained from dried sediments (1:3 ratio) and tested using Caenorhabditis elegans, assessing mortality, locomotion and growth as end points. Transcriptional effects associated with various toxicity mechanisms were evaluated using GFP-related transgenic strains (mtl-2, sod-4 and gst-1). Some trace metals enriched along the course of the river, especially Hg and V. Sediment extract-induced lethality was low (1.5–6.4%); however, nematode growth and locomotion decreased downstream the river, showing inhibition rates up to 23.3 and 35.4%, respectively. Extracts from downstream points increased the mRNA expression of tested genes compared to that elicited by the most upstream site, with greater values on stations receiving domestic sewage and mining outputs. Cobalt and lead were positively associated with metallothioneins and gst-1 expression. In short, coal mining areas should be closely monitored for trace-element release and their impact on biota. The Colombian government should implement laws and programs to protect key ecosystems from mining activities, as a commitment to sustainable development goals.

Dynamics of major and trace elements during leaf litter decomposition in semi-arid mangrove subject to urban runoff.

This study examined the dynamics of major elements and trace metals (TM) during litterfall decomposition in two mangrove forests-control and urban-along New Caledonia's coast. A litterbag experiment was carried out for 72days for the two main species (Rhizophora stylosa, and Avicennia marina) of the island. Results showed that the urban runoff enhances the leaching of some major elements (K, Mg, Na) during litter decomposition. The enrichment of TM in litter is also faster at the urban site. The dynamics of some major elements and TM are rather influenced by species metabolisms or element's characteristics such as Mn which does not increase in concentration in the decomposing litter. This study concludes that urban runoff accelerates the leaching of major elements and the enrichment of TM during leaf litter decomposition in mangrove forests, with species-specific factors and environmental conditions also playing significant roles in influencing these dynamics.

Iron metabolism dysfunction in neuropsychiatric disorders: Implications for therapeutic intervention.

Iron is a trace metal that takes part in the maintenance of body homeostasis by, for instance, aiding in energy production and immunity. A body of evidence now demonstrates that dysfunction in iron metabolism can have detrimental effects and is intricately associated with the development of neuropsychiatric disorders, including Major Depressive Disorder (MDD), anxiety, and schizophrenia. For instance, changes in serum and central nervous system (CNS) levels of iron and in proteins mediating iron metabolism have been documented in patients grappling with the aforementioned diseases. By contrast, targeting iron metabolism by using iron chelators, for instance, has proven to be effective in alleviating disease burden. Therefore, here we review the state-of-the-art regarding the role of iron metabolism and its dysfunction in the context of neuropsychiatric disorders. Furthermore, we discuss how targeting iron metabolism can be an effective therapeutic option to tackle this class of diseases. Finally, we discuss the mechanisms linking this dysfunction to behavioral changes in these disorders. Harnessing the knowledge of iron metabolism is not only key to the characterization of novel molecular targets and disease biomarkers but also crucial to drug repurposing and drug design.

Mapping trace metal footprints: Distribution, sources, and risk assessment in coastal sediments near a heavy industrial zone in Bangladesh.

This study investigated nine trace metals (Cr, Co, Cu, Cd, Ni, Mn, Fe, Zn, and Pb) concentrations of coastal sediments adjacent to a heavily industrialized area of Bangladesh using AAS. The most prevalent metals were zinc, with lesser amounts of Cd and Co. Pb, and Cd levels were higher than world standards, with a considerable enrichment of Pb at station 9. Ecological risk assessments showed moderate to high contamination, particularly by Pb and Cd. The Nemerow integrated pollution index demonstrated that overall pollution was low, but the levels about Cd were still concerning. All stations had hazard indices below 1 but chronic exposure to Ni, presents grounds for concern. Industry, urbanization, traffic, and agricultural runoff along with lithogenic sources have been identified to be the main sources of pollution using receptor modeling. The outcomes underscore the urgency that management measures must be taken to safeguard ecosystem and public health.

Temporal variations of metals and trace elements in tuna spines from the canary islands from 1990s to 2000s

Tuna, due to their position in the food web, serve as excellent biomonitors for assessing the health of marine ecosystems. Analyzing their organs and tissues provides valuable insight into element concentrations, as tuna possess the capacity to bioaccumulate pollutants. In the present study, 12 trace elements and metals (Al, B, Cd, Co, Cr, Cu, Fe, Li, Mo, Ni, Pb, Zn) were analyzed in dorsal fin spines samples of four tuna species: Katsuwonus pelamis, Thunnus albacares, Thunnus obesus and Thunnus thynnus from individuals captured in the surrounding waters of the Canary Islands, between 1990 and 2007. To analyze the data, descriptive statistics and one-way and two-way PERMANOVAs were carried out, with species factor and decade-species as factors, respectively. The highest concentrations were recorded for the elements: Al, Fe, B and Zn, with greater significant differences between species in the concentrations of Cu, and in both decades, in Fe, Pb and Zn. The comparison of the concentrations of elements between decades showed a decrease in them, from the 90s to the 2000s. There is no similar information on the metal content in spines for these species, providing relevant information, which may be of interest to future studies.

Comprehensive assessment of straw returning with organic fertilizer on paddy ecosystems: A study based on greenhouse gas emissions, C/N sequestration, and risk health.

High greenhouse gas emissions and soil deterioration are caused by the overuse of chemical fertilizers. To improve soil quality and crop productivity, it is necessary to utilize fewer chemical fertilizers to achieve sustainable agriculture. Organic substitution is a scientific fertilization strategy that will benefit future agricultural productivity development, little is known about how it affects the heavy metal content and trace gas emissions in rice grains. A field experiment using straw return to the field (SRF), organic fertilizer application (OFA), and their combination (SRF/OFA) fertilization strategies. The results demonstrated that SRF, OFA, and SRF/OFA increased the yield by 19.40%, 22.39%, and 28.36% than the natural growth control group (NG). The OFA has the highest STN stock and SRF/OFA has the highest STN sequestration rate, while SRF achieved the highest SOC stock and sequestration rate. The OFA reduced CO2, CH4, and N2O emissions by 17.73%, 71.87%, and 86.06%, resulting in a minimum global warming potential and greenhouse gas intensity yield among these strategies. Cumulative seasonal CO2 and CH4 emissions were negatively correlated with soil paddy soil C/N and C/P (P<0.05). Moreover, Cu, Cd, and Pb contents in grain were reduced by 66.18%-70.31%, 35.45%-40.91%, and 76.62%-77.92%, respectively. The health risk evaluation revealed that all metals had a target hazard quotient of <1, except for NG. The hazard index (0.42-0.53), which measures the additive effects of contaminants, exceeded the threshold. The implementation of the organic alternative strategy can reduce the trend of increasing surface pollution, slow down the excessive utilization intensity of agricultural resources, and encourage the development of a greener, more sustainable agricultural way.

Occurrence, seasonal distribution and probabilistic source-specific health risk assessment of dissolved trace metals in southwestern rivers, Nigeria

Occurrence, seasonal distribution and probabilistic source-specific health risk assessment of dissolved trace metals in southwestern rivers, Nigeria

Use of the diffusive gradients in thin-films (DGT) technique for smart rapid biomonitoring of trace metals in aquaculture systems.

It is of interest to explore the capabilities of the diffusive gradients in thin-films (DGT) as a substitute for smart biomonitoring of metals in aquaculture waters. DGT deployment and transplantation experiments of scallops Argopecten irradians were carried out in the coastal aquaculture waters. The results showed that DGT-labile metal concentrations were relatively stable in the aquaculture and they were in descending order: Zn>Ni>Cu>Pb≈Cd. The scallop A. irradians exhibited different abilities of taking up the studied metals from the ambient aquatic environment. Importantly, it demonstrated that DGT responded quicker than biomonitoring of scallops. Overall, it suggested DGT technique as a rapid monitoring method for metal contamination in aquaculture waters and laid a foundation for the standardization of the DGT technique. Besides, it suggested that high organic matter may have a great influence on DGT-labile concentrations, which should be investigated in more detail.

Pure CO2 and impure CO2-SO2-NO-O2 reactions with carbon storage site underlying seals: Coaly mudstones and carbonate cemented sandstones.

The transition to net zero emissions requires the capture of carbon dioxide from industrial point sources, and direct air capture (DAC) from the atmosphere for geological storage. Dissolved CO2 has reactivity to rock core, and while the majority of previous studies have concentrated on reservoir rock or cap-rock reactivity, the underlying seal formation may also react with CO2. Drill core from the underlying seal of a target CO2 storage site was reacted at in situ conditions with pure CO2, and compared with an impure CO2 stream with SO2, NO and O2 that could be expected from hard to abate industries. Argillaceous sandstones, mudstones, coaly mudstones, and carbonate cemented sandstones of the Moolayember Formation, Bowen Basin, had significant natural alteration of feldspar to kaolinite creating porosity, with clays, siderite and textured ankerite filling and rimming porosities of 3.5 to 15.8%. Synchrotron XFM quantified Mn mainly hosted in siderite veins and cements, Sr and Rb in feldspar, and Pb, Th and Sr in monazite. Pb was also in siderite; with As mainly in pyrite and associated with ankerite. On pure CO2 or impure CO2 reaction, ankerite and siderite dissolution, Fe-chlorite leaching, and apatite or sulphide alteration occurred. With the impure CO2 stream Fe-oxides precipitated on rock surfaces especially in argillaceous sandstone. Ferroan carbonates, calcite, and Fe oxides containing Cr were also precipitated. Ankerite and siderite dissolution released increasing concentrations of dissolved Ca, Mg and Mn from carbonate cemented core that were higher with mixed gas injection. Argillaceous sandstone however released higher concentrations Si, Rb, Co and Zn. Dissolved Fe initially increased then decreased in impure gas experiments via Fe oxide precipitation, and Pb, Ni, Cr, REE also increased and subsequently decreased. Geochemical modelling predicted that Fe was mobilised mainly from reaction of siderite and Fe chlorite. Mainly carbonates (siderite, ankerite) and chlorite dissolution released trace metals, with several metals also initially mobilised by desorption and exchange. Precipitated Fe oxides provided adsorption sites to adsorb a portion of metals from solution. These reactions are also relevant to CO2 streams from DAC that could be expected to contain O2 and to potential reactions in overlying aquifers.

Trace metals and Mo isotopic fractionation in Skagerrak sediments–effects of different oxygen conditions

The Skagerrak is the main depot center for organic matter and anthropogenic pollutants from the entire North Sea. Changes in ocean circulation or suspended matter supply might impact the sediment redox conditions. Indeed, little is known about the response of Skagerrak sediment and associated pollutants to different oxygen levels. We investigated sediments from three stations within the Skagerrak and incubated them for up to twelve months under aerobic and anaerobic conditions. Furthermore, we present the first δ98/95Mo data for Skagerrak sediment profiles and the incubations to be utilized as a redox tracer. The sediment profiles of metals reflected anthropogenic pollution (Cu, Ni, Pb) but differed regionally with redox conditions. We differentiated redox conditions mainly by sediment and porewater Fe, Mn, Mo and δ98/95Mo. In aerobic incubations, no Mn or Fe reduction was detected, while under anaerobic conditions, initial Mn and Fe reduction decreased after approximately three months. Under anaerobic conditions, a strong isotopic fractionation of Mo in the dissolved phase was found, reaching up to 5.03 ± 0.10‰, probably caused by incomplete thiolation of molybdate under low hydrogen sulfide levels. During the incubations, Cd, Cu, Ni, Pb were mobilized. While Cu and Cd were mobilized under aerobic conditions, Ni and Pb mobilization depended mainly on remineralization and redox conditions. Our results show that changes in oxygen conditions in the Skagerrak can have significant effects on the (legacy) metals stored in the sediment over the past decades.Graphical

Revolutionizing Oral Cancer Care: The Therapeutic Potential of Coenzyme Q10 and Balanced Trace Metals

Revolutionizing Oral Cancer Care: The Therapeutic Potential of Coenzyme Q10 and Balanced Trace Metals

Tracking the Dispersal of River Water, Atmospheric Deposition, and Shallow Sedimentary Trace Metal Inputs From the Congo Region Into the South Atlantic

AbstractRecent work has revealed the presence of an offshore near‐surface plume of dissolved trace elements in the South Atlantic Ocean (SAO). Dissolved Fe (dFe) supply from the Congo plume is equivalent to ∼40% of the annual atmospheric dFe supply to the SAO. However this plume is not captured by biogeochemical models, raising questions about its exact sources. To help understand the potential source mechanisms, we use particle tracking experiments to investigate elemental distributions. Results suggest that elevated concentrations of some elements in the Congo plume are primarily sourced from river discharge and wet atmospheric deposition with minimal influence from shelf sediments. River discharge is the main source in shelf regions and some off‐shelf regions, whereas atmospheric deposition dominates the area to the southwest of the Congo River outflow. A quantitative analysis along 3S specifically for dFe suggests a decrease in the contribution of river discharge from 90% to 30% moving off‐shelf, with a corresponding increase in the contribution of atmospheric deposition. Within the shelf zone, atmospheric deposition accounts for roughly 20%–40% and could be a major source of dFe around the river mouth. Integration of data from cruise GA08 reinforces the finding that wet deposition augments the concentrations of dFe, manganese (dMn), and cobalt (dCo) at distances over 1,000 km from the river mouth. Given present‐day patterns of nitrate, Fe, and Co limitation for primary producers in the SAO, changing rainfall patterns may have long‐term implications for both regional elemental budgets and ecologically dependent processes sensitive to trace element ratios.

Speciation of Trace Metals in the Bottom Sediments of the Mozhaisk Reservoir and the Moskva River

The speciation of heavy metaf Geology, ls (Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in the bottom sediments of the Mozhaisk Reservoir and the Moskva River is described. They were characterized using the Tessier sequential selective extraction procedure trace element concentrations determined by inductively coupled plasma–mass spectrometry (ICP-MS). The bottom sediments of the Mozhaisk Reservoir are characterized by higher concentrations of the examined metals compared to the channel alluvium of the Moskva River. In this case, the most widespread metal compounds in the bottom sediments of the Mozhaisk Reservoir are firmly bound (stable form) to the mineral matrix. High concentrations of the firmly bound forms of metals (Co, Ni, Cu, Zn, Cd, Pb, and Fe) in the bottom sediments are due to an increased proportion of the silt fraction (0.1–0.01 mm) entering the reservoir due to abrasion of its shores. The only exceptions are Mn and Cd, which are present in labile compounds with carbonates and hydroxides of iron and manganese. In the bottom sediments of the Moskva River, strongly bound forms prevail for most metals—for Ni, Zn, and Cd, they are complex compounds with Fe and Mn hydroxides; for Co, Cu, Pb, and Fe, they are compounds with stable silicate minerals. The proportion of labile bioavailable forms of metals in the bottom sediments of the Moskva River is higher than in the reservoir due to anthropogenic input. Among the labile forms of the metal compounds, carbonates predominate. The proportion of elements in the most mobile exchange form and in compounds with organic matter is not large and does not exceed 14% for most elements. The only exceptions are Co and Cd, for which the concentration of the exchange form reaches 25%.

Lower Contents of Soil Organic Matter, Macro-Nutrients, and Trace Metal Elements in the Longleaf Pine Forests Restored from the Mixed Pine and Hardwood Forests

Restoration of the longleaf pine forest ecosystem is critical for biodiversity. However, the mixed hardwood forests can grow naturally in the same area. There are limited studies comparing soil organic matter and nutrient contents for restoring longleaf pine forests from the mixed hardwood forest areas in the southeastern USA. In this study, a comparison of the contents in soil organic matter, macro-nutrients, trace metal elements, and litterfall amount, was conducted on the 16 forest stands (4 treatments including stand stages × 4 replicants) at William B. Bankhead National Forest in Alabama through the space-replace-time approach. The results indicate that longleaf pine forests have lower contents of soil organic matter, macro-nutrients, most trace metal elements, and litterfall amount than mixed hardwood forests. However, longleaf pine forests have higher soil Ca, Ba, and Pb contents than hardwood forests. Soil Fe content has more correlations with the contents of other metal elements than soil Mn. The results suggest that multiple ecosystem functions, including soil ecology, must be considered in the regional restoration of the longleaf pine ecosystem. Longleaf pine forests with a certain amount of mixed hardwood trees may be a good way to maintain soil organic matter and nutrients.