Toxic Metals Research Articles

The preparation of polyaniline/graphene/polypropylene nanocomposite and its novel antibacterial activity

AbstractThe demand for polymers with antibacterial properties is increasing in food packaging industry and medical supplies. Antibacterial additives without toxic metal ion release are crucial for health and safety but still have challenges. Herein, polypropylene (PP) nanocomposite was prepared with polyaniline/graphene nanocomposite (PANI/GNP) as a green antibacterial additive due to its electrostatic, free radical, and nanoknife effect synergistic antibacterial mechanisms. To improve the dispersibility of PANI/GNP, nanosilica coating on PANI/GNP was constructed successfully with in situ condensation polymerization of epoxy functionalized ethyl orthosilicate to obtain EP‐nSiO2‐PANI/GNP. EP‐nSiO2‐PANI/GNP with a thin nanosilica coating has a significantly improved thermal stability as compared with that of PANI/GNP characterized by TGA. The EP‐nSiO2‐PANI/GNP presents a nanoscale disperse state in PP nanocomposite and thus enhances the melt viscosity and storage modulus accordingly characterized by TEM and Rheology. The EP‐nSiO2‐PANI/GNP/PP filled with 0.5 wt% of EP‐nSiO2‐PANI/GNP demonstrates antibacterial activity of 100% against both Escherichia coli and Staphylococcus aureus.Highlights In situ condensation polymerization to prepare EP‐nSiO2‐PANI/GNP. EP‐nSiO2‐PANI/GNP has enhanced dispersion stability. EP‐nSiO2‐PANI/GNP with a thin nanosilica coating has a good thermal stability. PP nanocomposite with 0.5 wt% filler has excellent antibacterial activity. The electrostatic, free radical, and nanoknife effect antibacterial mechanism.

Toxic metal accumulation, health risk, and distribution in road dust from the urban traffic-intensive environment.

Owing to increasing levels of potentially toxic metals in road dust, air pollutants suspended in the air, pose significant health risks due to rapid, unplanned urbanization and industrialization. This study investigated the pollution status and health risks of trace metals (i.e., Cr, Cd, Ni, Cu, and Pb) in road dust collected from 16 locations across six land-use categories in Eskişehir, Türkiye, including residential, roadside, traffic, tram stations, and car industrial areas. The analysis of trace metals revealed distinct types of urban pollution based on these functional areas. In areas with heavy traffic, high concentrations of the elements, especially Zn, Cr, and Ni, would indicate significant toxic metal pollution. The overall contamination was evaluated using three indices: enrichment factor (EF 0.45-65.75), geo-accumulation index (Igeo - 2.50-4.18), and pollution index (PI 0.27-27.22). Human health risks of potentially toxic trace metals in urban road dust were evaluated for children and adult groups based on hazardous index (HI) and total cancer risk (TCR). The health risk assessments revealed that children (mean HIchildren 8.62E - 01; TCRchildren 6.99E + 04) are more vulnerable to toxic metal exposure than adults (mean HIadults 1.01E - 01; TCRadults 3.01E + 04), with ingestion being the primary exposure route over dermal contact and inhalation. In conclusion, we have captured the interaction between road dust and health risks, especially for children.

Evaluation of human and ecological health risks associated with the potentially toxic heavy metals in groundwater of Vellore city, Tamil Nadu, India

Groundwater pollution by heavy metals is a significant and alarming threat globally, through its chronic effect on human health and ecosystem. The current study evaluated the identification and risk assessment of heavy metals in groundwater of the Vellore city, Tamilnadu, India. Groundwater samples were collected from 32 locations over a continuous period of 2022–2023 for every three months on seasonal basis. The samples were analysed for pH, Total Dissolved Solids (TDS), Hardness and heavy metals (Al, As, Ba, Cd, Cu, Pb, Al and Zn). The analysed mean concentrations of these heavy metals were found in the order: As > Cd > Pb > Ba >Zn >Al> Cu. Elevated concentrations of heavy metals were observed in 2022, likely influenced by rainfall and land use patterns. Heavy metals such as Al, As, Pb, and Cd exceeded the BIS limits and whereas Ba, Cu, and Zn concentrations remain within desirable limits. Groundwater Quality Index (GWQI) classified 41% as 'unfit for drinking'. Ecological risk indices (ERI) indicate significant contamination in 34% of samples, with Al and Pb being primary contributors. Non-carcinogenic health risk assessments reveal, chronic hazards, where children facing higher risks followed by men and women groups. Carcinogenic risk assessments indices such as Heavy metal pollution Index (HPI) shown 25% of samples in critical quality, Heavy metal Evaluation Index (HEI) evaluated all samples were in low contamination and Contamination Index (CI) shown 72% samples under high contamination posing high risk to humans. Probable Cancer Risk (PCR) values for As, Pb, and Cd exceed acceptable ranges across all demographic groups posing cancer risk to humans particularly children. The present study highlights the need for groundwater treatment and regulatory interventions to mitigate health and ecological risks due to the contamination of heavy metals in Vellore city.

Synthesis and characterization of allyl mannitol cross-linker based novel hydrogel for capturing of toxic metal ions from aqueous solution

ABSTRACT Three grades of allyl-mannitol cross-linker-based hydrogel (AMCLHs hydrogel) have been synthesized with the help of acrylic acid and acrylamide monomers using a free radical co-polymerization technique. The three prepared grades of AMCLHs hydrogel have been referred to as AMCLHs-1, AMCLHs-2, and AMCLHs-3, respectively. The prepared AMCLHs hydrogels have been characterized by several analytical techniques viz. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG) analysis, point of zero charge (ΔpHPZC), analysis, and scanning electron microscope (SEM) analysis, respectively. The synthesized hydrogels have been utilized for the elimination of Cu2+ and Co2+ ions from wastewater. The properties of prepared AMCLHs hydrogels, i.e. swelling and water retention ratio have been studied in distilled water under optimized conditions. The maximum swelling ratio of the best grade of hydrogel (AMCLHs-1) has been found to be 400.5 g/g with the water retention ratio of 75.09% during 24 h. These findings indicate the AMCLHs-1 hydrogel has remarkable swelling and water retention capacity. The maximum metal ion removal efficiency of AMCLHs-1 hydrogel from aqueous solutions has been found to be 96.6% for Cu2+ and 94.2% for Co2+ ions under optimum conditions. The experimental data fitted well with the Langmuir and Freundlich adsorption models, revealing maximum adsorption capacities of 431.03 mg/g for Cu2+ ions and 414.93 mg/g for Co2+ ions, respectively. In addition, the rate for the adsorption of Cu2+ and Co2+ ions onto AMCLHs-1 hydrogel follows both Pseudo first and second-order kinetic models. The negative ΔG values indicate that the adsorption process occurs spontaneously, while positive ΔH values suggest that the adsorption process is exothermic in nature. The prepared AMCLHs hydrogel is reusable and exhibits high desorption efficiency with 87.63% for Cu2+ and 85.21% for Co2+ metal ions even after the fourth cycle. Overall, AMCLHs hydrogel is a cost-effective and reusable adsorbent that possesses a significant potential for heavy metal ion removal from aqueous solutions.

Decoupling Sources of Anthropogenic Influences on Sediments of the Visovac Lake (Krka National Park, Croatia) Using Multiparametric Approach.

Historical changes of sediment characteristics and levels of inorganic and organic contaminants were studied in dated sediment cores from the Visovac Lake, situated in the Krka National Park, Croatia, to identify the main sources of anthropogenic pressures on this highly protected system. Depth distributions of lithogenic elements showed a steady decrease of terrigenous inputs due to the reduction in agricultural activities in the area, which was particularly pronounced during the 1991-1995 war in Croatia. Vertical and longitudinal distributions of Cd and Zn indicated that they are predominately of anthropogenic origin. The historical profiles of these toxic metals coincide well with the recorded production of metal industry in the upper reach of the Krka River with a sharp decrease reflecting the interruption by the war and slow recovery afterwards. By contrast, the recovery of the tourist industry in Krka NP after the war was accompanied by increasing contamination by elements characteristic of boat and car traffic (Sn, Cu, Pb) as well as oil pollution. The contamination with polycyclic aromatic hydrocarbons and polychlorinated biphenyls was only moderate. Although levels of metallic and organic contamination can be considered relatively low, the observed shift from industrial to tourism-related sources indicated that touristic activities should also be regarded as a possible threat for this vulnerable karst aquatic ecosystem.

Assessing the Toxicity of Metal- and Carbon-Based Nanomaterials In Vitro: Impact on Respiratory, Intestinal, Skin, and Immune Cell Lines.

The field of nanotechnology has experienced exponential growth, with the unique properties of nanomaterials (NMs) being employed to enhance a wide range of products across diverse industrial sectors. This study examines the toxicity of metal- and carbon-based NMs, with a particular focus on titanium dioxide (TiO2), zinc oxide (ZnO), silica (SiO2), cerium oxide (CeO2), silver (Ag), and multi-walled carbon nanotubes (MWCNTs). The potential health risks associated with increased human exposure to these NMs and their effect on the respiratory, gastrointestinal, dermal, and immune systems were evaluated using in vitro assays. Physicochemical characterisation of the NMs was carried out, and in vitro assays were performed to assess the cytotoxicity, genotoxicity, reactive oxygen species (ROS) production, apoptosis/necrosis, and inflammation in cell lines representative of the systems evaluated (3T3, Caco-2, HepG2, A549, and THP-1 cell lines). The results obtained show that 3T3 and A549 cells exhibit high cytotoxicity and ROS production after exposure to ZnO NMs. Caco-2 and HepG2 cell lines show cytotoxicity when exposed to ZnO and Ag NMs and oxidative stress induced by SiO2 and MWCNTs. THP-1 cell line shows increased cytotoxicity and a pro-inflammatory response upon exposure to SiO2. This study emphasises the importance of conducting comprehensive toxicological assessments of NMs given their physicochemical interactions with biological systems. Therefore, it is of key importance to develop robust and specific methodologies for the assessment of their potential health risks.

The Protective Effect of the Supplementation with an Extract from Aronia melanocarpa L. Berries against Cadmium-Induced Changes of Chosen Biomarkers of Neurotoxicity in the Brain-A Study in a Rat Model of Current Lifetime Human Exposure to This Toxic Heavy Metal.

Since even low-level environmental exposure to cadmium (Cd) can lead to numerous unfavourable health outcomes, including damage to the nervous system, it is important to recognize the risk of health damage by this xenobiotic, the mechanisms of its toxic influence, and to find an effective protective strategy. This study aimed to evaluate, in a female Wistar rat model of current human environmental exposure to Cd (1 and 5 mg/kg of diet for 3-24 months), if the low-to-moderate treatment with this element can harm the brain and whether the supplementation with a 0.1% Aronia melanocarpa L. (Michx.) Elliott berries (chokeberries) extract (AE) can protect against this effect. The exposure to Cd modified the values of various biomarkers of neurotoxicity, including enzymes (acetylcholinesterase (AChE), sodium-potassium adenosine triphosphatase (Na+/K+-ATPase), phospholipase A2 (PLA2), and nitric oxide synthase 1 (NOS1)) and non-enzymatic proteins (calmodulin (CAM), nuclear factor erythroid 2-related factor 2 (Nrf2), and Kelch-like ECH-associated protein 1 (KEAP1)) crucial for the functioning of the nervous system, as well as the concentrations of calcium (Ca) and magnesium (Mg) and some metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in the brain tissue. The co-administration of AE, partially or entirely, protected from most of the Cd-induced changes alleviating its neurotoxic influence. In conclusion, even low-level chronic exposure to Cd may adversely affect the nervous system, whereas the supplementation with A. melanocarpa berries products during the treatment seems a protective strategy.

High-affinity potassium transporter TaHAK1 implicates in cesium tolerance and phytoremediation

Cesium (Cs) is a toxic alkaline metal affecting human health. Plant high-affinity K transporters (HAKs) involved in Cs uptake and transport have been identified in several plants. However, the molecular regulatory mechanisms of Cs uptake and transport, and homeostasis between Cs and K by HAKs remain unknown. In this study, TaHAK1 was overexpressed in rice (TaHAK1-OEs) to evaluate Cs absorption capacity and the Cs and K homeostasis mechanisms. Results showed that TaHAK1 promoted seedling growth by fixing Cs in the root cell wall and modifying Cs distribution. Transcriptome and bioinformatics analyses revealed that 37,828 differentially expressed genes (DEGs) were significantly induced in TaHAK1-OEs, of which the pathways involved in cell wall biosynthesis and ion absorption transport were notably affected including genes, XTHs, CSLEs, HAKs, and ABCs. Moreover, under Cs-contaminated soil, TaHAK1-OEs exhibited improved Cs tolerance by decreasing Cs accumulation and increasing K content in different tissues, particularly in the grains, indicating that TaHAK1 acts as a candidate gene for screening genetic modification of Cs phytoremediation and developing low-Cs-accumulation rice varieties. This study provides new insights into the uptake and translocation of Cs and the homeostasis of Cs and K in plants, and also supplies new strategy to improve phytoremediation efficiency.

Transfer of potentially toxic metals and metalloids from terrestrial plants to arthropods—A mini review

Transfer of potentially toxic metals and metalloids from terrestrial plants to arthropods—A mini review

Geochemical characterizations, pollution monitoring, and health risks of toxic metals released from an active phosphate mine in the Western Desert, Egypt

Geochemical characterizations, pollution monitoring, and health risks of toxic metals released from an active phosphate mine in the Western Desert, Egypt

One‐Pot Synthesis of Pyrazoles from Sulfonyl Hydrazides and Alkynyl Ketones Using Environmentally Benign Sulfonium Iodate (I) Reagent

AbstractPyrazole is an omnipresent moiety in many natural products and pharmaceutically active compounds. Here, we have developed a simple and dynamic method for one‐pot synthesis of substituted pyrazoles through the intramolecular cyclization of hydrazides and alkynyl ketones, using a novel sulfonium saltbased iodate (І) reagent system. This method has the advantage that it proceeds in a one‐pot, without isolating a less stable hydrazone intermediate. Hypervalent iodine‐based reagents are an environmentally benign and greener option to toxic metal oxidants; they have an extensive application in metal‐catalyst‐free reactions, and this reaction proceeds in less time with high yields.

Calcium oxide nanoparticles ameliorate cadmium toxicity in alfalfa seedlings by depriving its bioaccumulation, enhancing photosystem II functionality and antioxidant gene expression

Cadmium (Cd) is a highly toxic and carcinogenic pollutant that poses significant risks to living organisms and the environment, as it is absorbed by the plant roots and accumulates in different parts of crop during its production. A promising sustainable strategy to counteract these threats to use calcium oxide nanoparticles (CaO-NPs) as soil supplements in fodder crops. This approach has shown notable morpho-physiological and biochemical improvements under metal toxicity conditions. However, the specific mechanisms driving Cd tolerance, particularly at physio-biochemical level and antioxidant related genes expression in fodder crops including alfalfa remain unexplored. CaO-NPs supplementation can trigger various signaling pathways that lead to enhance the photosynthetic pigments formation, stomatal conductance, CO2 assimilation rate and quantum yield of photosystem II. In this study, we evaluated various doses of CaO-NPs (0, 25, 50, and 100 mg kg−1) for their efficacy in reducing Cd bioavailability and toxicity in alfalfa plants. Our results demonstrated that Ca2+ and Cd2+, which share the same ionic radius, compete for ion transport through channels. The small size and high availability of CaO-NPs facilitate their rapid translocation within plant tissues, reducing metal uptake by 61 % in shoots and 30 % in roots. Notably, application of CaO-NPs at 100 mg kg−1 significantly increased shoot length (44 %) and root lengths (35 %) as compared to Cd-treated control plants. The highest dose of CaO-NPs also improved photosynthetic efficiency and gas exchange attributes including (gs, Tr, Pn and Ci) by 66 %, 27 %, 33 % and Ci 21 %, respectively, compared with the Cd treated control. Moreover, CaO-NPs (at 100 mg kg−1) alleviated metal-induced oxidative stress by boosting antioxidant enzyme activity like SOD (25 %) POD (42 %), CAT (72 %) and APX (87 %) and diminishing reactive oxygen species (ROS) production when compared with sole Cd treatment. Scanning and transmission electron microscopy revealed that CaO-NPs positively impacted stomatal conductance and mitigated Cd toxicity in leaf ultrastructure. Additionally, the highest dose of CaO-NPs markedly upregulated the expression of antioxidant-related genes, MsCu/Zn SOD, MtPOD, MtCAT, and MtAPX in roots and shoots by 0.67 and 1.03 fold-change (FC), 0.61 and 0.53 FC, 0.54 and 0.88 FC, and 0.46 and 0.66 FC, respectively. In conclusion, CaO-NPs demonstrate significant potential for environmentally friendly mitigation of Cd stress in alfalfa by reducing its uptake, thereby supporting sustainable agriculture.

Heavy metals toxicity in edible bivalves and risk exposure to humans through its consumption from Adyar Estuary, Tamilnadu, India – A baseline study

The Adyar estuary, situated at the heart of Chennai city, India, has been subjected to significant anthropogenic pollution over the past decade due to rapid urbanization and industrialization.This study endeavored to explore the bioaccumulation patterns of heavy metals within bivalve species including Perna viridis, Mercenaria mercenaria, and Lamellidens marginalis. Additionally, it aimed to assess the concentrations of heavy metals present in water samples obtained from ten discrete stations within the Adyar estuary across different seasonal periods. To better understand the dynamics of contamination, metal pollutants including Cd, B, Cu, Fe, Mn, Pb, and Zn were analyzed in the soft tissues (Gill, Kidney, and Muscle) of the bivalves using Atomic Absorption Spectrophotometer (AAS) (ELICO's SL- 176). The study also investigated the seasonal changes in biochemical constituents affecting the nutritional quality of these edible bivalves following conventional methods, and estimated the risk (both carcinogenic and non-carcinogenic) to consumers. Results showed that the biochemical constituents of Perna viridis and Mercenaria mercenaria were comparatively lower than those of the freshwater bivalve Lamellidens Marginalis (p > 0.05). Heavy metal accumulation in the mussels followed the order Mn > Zn > Cu > Pb > Fe > Cd > B. The highest uptake of metals by the bivalves occurred during the post-monsoon season, while the least uptake was observed during the monsoon season. The overall metal burden for the studied species followed the descending order M. mercenaria >P. viridis >L. marginalis. The study indicated that both carcinogenic and non-carcinogenic risks to humans from consuming these mussels were higher due to the excessive accumulation of metals Zn and Mn in all three studied bivalves.

Occupational exposure assessment of heavy metals among construction workers in Rawalpindi Pakistan

Construction is one of the primary drivers of development and economic activity in Pakistan. Many activities are performed at the construction site including cement mixing, carpentry, and painting. Workers working in these activities are exposed to toxic heavy metals. Due to exposure to these heavy metals, subjects are at high risk of developing diseases mainly respiratory diseases. Human hair and nail samples of construction workers in Rawalpindi, Pakistan were collected to assess the heavy metals. Heavy metals such as Al, As, Cd, Cr, Ni, K, Pb, and Zn were analyzed in the hair and fingernails of the construction workers. To determine the level of selected heavy metals, Inductively Coupled Plasma optical emission spectrometry was used. Results revealed that Al was the highest with a mean concentration of 7.54 μg/g in all three groups. Whereas Cd was below the detection limit. Heavy metal concentration was high in hair (1.77 μg/g) in two groups including cement mixing and carpentry. However, in the carpentry group heavy metal concentration was high in nails (1.19 μg/g). Additionally, the workers of the carpentry group have higher metal concentrations when compared to the other two groups and this group was at high risk of toxic metal exposure. After the correlation analysis, the results revealed that age was significantly correlated to body burden of metals (r = 0.496, p ≤ 0.05). Moreover, some of the heavy metals in hair and nails were significantly correlated with each other. Since all groups, especially carpenters, show high levels of heavy metals, there is a need for regular monitoring of heavy metals at construction sites. Most importantly, the implementation of training programs is needed to raise awareness among construction workers.

A comprehensive review on phytoremediation of fly ash and red mud: exploring environmental impacts and biotechnological innovations.

Fly ash (FA) and red mud (RM) are industrial byproducts generated by thermal power plants and the aluminum industry, respectively. The huge generation of FA and RM is a significant global issue, and finding a safe and sustainable disposal method remains a challenge. These dumps contain harmful trace elements that have a significant impact on the environment and human health. It contributes to air, water, and soil pollution, disrupting the delicate balance of the ecosystems. It also introduces toxins into the food chain through biomagnification. Utilizing a vegetation cover can assist in addressing environmental health concerns associated with FA and RM dumps. Nevertheless, the presence of alkaline pH, toxic metals, the absence of soil microbes, and the pozzolanic properties of both FA and RM pose challenges to plant growth. Taking a comprehensive approach to the ecological restoration of these dumps through phytoremediation is crucial. This review examines the role of various factors in the ecological restoration of FA and RM dumps, specifically the use of naturally occurring plants. However, the issue of slow plant growth due to a lack of nutrients and microbial activities is being resolved through various advances, such as amendments in conjunction with organic matter, microbial inoculants, and the use of genetically modified plants. Research has demonstrated the benefits of using amendments to stimulate vegetation growth on FA and RM dumps. In this review, we explore various approaches to restoring FA and RM dumps and transforming them into productive sites that enhance the ecosystem services.

Solution-Crystalized AgBiS2 Films for Solar Cells Generating a Photo-Current Density Over 31mA cm-2.

In response to the toxic heavy metal absorbers in perovskite solar cells (PSCs), this work focuses on the development of an environmentally friendly simple solution-processed infrared (IR) absorber. In this work, a simple solution-crystallized IR-absorbing AgBiS2 film is reported by spin-coating silver, bismuth nitrates, and thiourea dissolved in dimethylformamide (DMF) to produce thick AgBiS2 film. Extensive optimization of the precursor concentrations thicknesses and conductive substrates used allow for obtaining 250nm AgBiS2 film with different crystal sizes. When applied as an absorber in solar cells, solution-crystalized AgBiS2 thick film delivers an extraordinarily high current density of over 31mA cm-2. The devices show high stability under continuous 100mW cm-2 illumination and when stored in the dark for more than six months. When the AgBiS2 layer is fabricated in a gradient fashion combining one layer of 0.25m and three layers of 0.5m precursor concentrations, the efficiency of 5.15% is registered which is the highest reported for the simple solution-crystallized AgBiS2 films.

Remediation quantum of organic amendments to immobilize potentially toxic heavy metals in wastewater-contaminated soils through maize cultivation

Wastewater is considered a good reservoir of mineral elements that can be used for agriculture, aquaculture, and some other activities after adopting suitable measures. The gap between supply and demand for water is increasing exponentially because of the abrupt boost to the world’s population. This poses a threat to human life as it has reached alarming levels in some parts of the globe. Normally, wastewater consists of liquid waste produced by commercial or industrial sources for daily use, consumption, and production. It is time to refocus our attention on a kind of circulating water system by reusing municipal wastewater for agricultural purposes, particularly irrigation. The recycled or treated water would be used as an alternative to fresh water. In the current study, the impact of various organic amendments was studied to mitigate the toxic effects of pollutants present in wastewater by cultivating maize as a test crop. The present study comprised five treatments replicated four times with a randomized complete block design under field conditions. In this experiment, the treatments included T1 (treatment 1) = control (wastewater-polluted soil without the application of any amendment), T2 = farmyard manure (FYM) at 2.5 tons ha-1 (hectare-1), T3 = FYM at 5.0 tons ha-1, T4 = compost at 2.5 tons ha-1, and T5 = compost at 5.0 tons ha-1. The application of FYM at 5.0 tons ha-1 (T3) was recorded as being the most effective as the maximum improvement was observed in soil characteristics such as pH, electrical conductivity (EC), sodium adsorption ratio (SAR), and organic matter, and for T3, these were 7.33, 2.22 dS m-1, 8.16, and 0.94%, respectively. T3 remained most superior in reducing the concentration of heavy metals in the soil; for example, lead, cadmium, nickel, and arsenic for T3 were 8.64, 1.34, 10.44, and 2.25 mg kg-1 (milligrams per kg), respectively. Maximum fresh biomass (fodder yield) of 9.98 tons ha-1 was harvested when FYM was applied at 5.0 tons ha-1 to the soil compared to 6.2 tons ha-1 in the control plot. The highest contents of nitrogen (1.20%), phosphorus (0.41%), and potassium (3.97%) were observed in maize plants for T3. In maize plants (T3), the concentration of lead, cadmium, nickel, and arsenic was reduced to levels of 1.92, 0.23, 2.28, and 1.25 mg kg-1, respectively. Therefore, it can be concluded from the findings of the experiment that the application of FYM significantly reduced heavy metal concentrations and improved soil health, along with maize crop growth and productivity.

Plant-derived biochar and salicylic acid as biostimulants for Lycopersicon esculentum under chromium toxicity conditions: Insights from physiochemical attributes, antioxidants, and relative gene expression

Chromium is a widespread toxic trace metal in cultivated lands owing to human actions, insufficient treatment, and unregulated disposal. Chromium toxicity is facilitated by the production of reactive oxygen species, which induce lipid peroxidation and damage the cellular membranes and nuclei. This study evaluated the preparation and characterization of Pterospermum-derived biochar based on a set of test categories from the International Biochar Initiative. The aim of this study was to assess the effectiveness of Pterospermum-derived biochar and salicylic acid (SA) in promoting the growth and biochemical attributes of tomato plants grown in Cr-contaminated soils. The results showed that Cr toxicity reduced root (42.86 %) and shoot (23.26 %) lengths, which subsequently increased (65 % root and 39.94 % shoot lengths) under SA and biochar treatments. Increased levels of superoxide anions (O2•-) (104.43 %), malondialdehyde (MDA) (115.53 %), and H2O2 (72.35 %) were observed in the Cr-treated tomato plantlets. The combined treatment of SA and biochar effectively reduced MDA, H2O2, and O2•- levels by 51.17 %, 36.89 %, and 45.53 %, respectively, under Cr toxicity conditions. In addition, the combined treatment with SA and biochar enhanced the activity and gene expression of dehydrogenase (7.06-fold), guaiacol peroxidase (6.51-fold), superoxide dismutase (7.90-fold), polyphenol oxidase (1.89-fold), glutathione-s-transferase (2.55-fold), ascorbate peroxidase (1.26-fold), and glutathione peroxidase (8.75-fold) under Cr toxicity conditions. The results highlight the combined treatment of biochar and SA as an effective amendment that offers an environment-friendly method for alleviating Cr toxicity and promoting growth and the antioxidative defense system in tomato plantlets.

Human health risk assessment of potentially toxic metals in fish (Cynoglossus sp.) commonly consumed in Nigeria

In order to determine the concentrations of certain metals that may be hazardous in widely consumed fish species (Cynoglossus sp.) in Nigeria, atomic absorption spectrophotometry was used. The main objectives were to determine the most likely sources of these metals and assess the potential health concerns connected with consuming fish. Fish samples were collected from Sabo market, Ile-Ife, Osun state. They were digested using HNO3 and H2O2 and subjected to elemental analysis (Fe, Zn, Mn, Pb, Cu, Cd, Co, and Cr) using atomic absorption spectrophotometer. The results showed that Lead (Pb) had the lowest mean concentration of 0.56 ± 0.01 mg/kg, while Zinc (Zn) had the highest average concentration of 12.88 ± 0.18 mg/kg. Strong and substantial correlations between the studied metals were shown by the analysis of the correlation matrix and cluster patterns. The study also evaluated a number of health risk parameters, including target hazard quotient, estimated daily intake, and cancer risk, which together suggested that consuming these fish samples posed health concerns for both adults and children. According to relative risk, seafood consumption raises the most alarm about Cd levels. The study came to the conclusion that due to the propensity for these potentially hazardous metals to bioaccumulate, only a moderate amount of these fish samples should be consumed. Additionally, it is strongly advised to discourage the disposal of domestic and industrial wastes into water bodies.

Acidocalcisome localization of membrane transporters and enzymes in Trypanosoma brucei.

Acidocalcisomes are acidic organelles rich in polyphosphate and calcium present in a variety of eukaryotes and important for osmoregulation and calcium signaling. Several proteins were postulated to localize to acidocalcisomes based on their morphological characteristics. We provide validation of the localization of ten10 acidocalcisome proteins by their co-localization with enzymatic markers. These findings reveal the roles of acidocalcisomes in the storage of toxic metals, and the presence of enzymes involved in palmitoylation and polyphosphate metabolism.