Nickel Contamination Research Articles

Optimization and Efficiency of Novel Magnetic-Resin-Based Approaches for Enhanced Nickel Removal from Water

Nickel contamination in water is a critical issue due to its toxicity and persistence. This study presents a novel magnetic resin, developed by modifying Lewatit® MonoPlus TP 207 with magnetite nanoparticles, to enhance adsorption capacity and facilitate efficient separation. A Definitive Screening Design (DSD) was employed to identify and optimize key parameters affecting nickel adsorption, including pH, resin dosage, initial nickel concentration, and the presence of competing ions (calcium and magnesium). The DSD analysis revealed that pH and magnesium concentration were the most significant factors influencing nickel removal. Optimal conditions were determined as pH 7, 270 min contact time, resin dosage of 0.5 mL/L, initial nickel concentration of 110 µg/L, calcium concentration of 275 mg/L, and magnesium concentration of 52.5 mg/L, achieving a maximum removal efficiency of 99.21%. The magnetic resin exhibited enhanced adsorption capacity and faster kinetics compared to the unmodified resin, leading to more efficient nickel removal. Moreover, its magnetic properties facilitated rapid separation from treated water, offering practical advantages for real-world applications. This study demonstrates the effective use of DSD in optimizing adsorption parameters and underscores the potential of magnetic resin as a sustainable and efficient adsorbent for water treatment.

Impact of lead and nickel contamination on metabolic health: Associations with diabetes mellitus in a pakistani cohort

Environmental exposure to heavy metals, particularly lead (Pb) and nickel (Ni), is implicated in chronic metabolic diseases, including diabetes mellitus (DM). This cross-sectional study assessed the Pb and Ni levels in groundwater using ICP-OES and urine samples collected from 2688 participants using ICP-MS. We aimed to establish the associations between Pb and Ni exposure and risk factors for DM and metabolic disorders. Groundwater analysis revealed the elevated levels of total dissolved solids, electrical conductivity, hardness, turbidity, Ni, and Pb, exceeding the WHO guidelines. The mean concentration of Pb in groundwater samples of study area was 0.025 mg/L which was higher than the WHO permissible limit of 0.01 mg/L. Similarly the mean concentration of Ni in groundwater samples of study area was 0.038 mg/L which was also higher than the WHO permissible limit of 0.02 mg/L. In human study, participants, categorized into Pb-detected and Ni-detected groups, exhibited significantly higher Pb and Ni levels and non-exposed non-diabetic groups. Ni-detected diabetics showed elevated Ni levels compared to non-exposed non-diabetics. Similarly, Pb-detected diabetics showed elevated Pb levels compared to non-exposed non-diabetics. These findings suggest a potential contribution of Pb and Ni exposure to DM development. The study also identified associations between heavy metal exposure and disruptions in various biomarkers related to DM, lipid profile, inflammation, oxidative stress, liver function, and kidney function. Pb-detected diabetics demonstrated elevated levels of glycemic index biomarkers, including fasting blood glucose (P < 0.0001) and HbA1c (P < 0.0001). Ni-detected diabetics exhibited increased inflammatory markers, such as CRP (P < 0.0001) and IL-6 (P < 0.0001). Both Pb and Ni exposure were associated with dyslipidemia, as indicated by elevated levels of total cholesterol (P < 0.0001) and LDL (P < 0.0001). Additionally, heavy metal exposure was linked to impaired liver and kidney function, supported by elevated levels of AST (P < 0.0001), ALT (P < 0.0001), creatinine (P < 0.0001), and blood urea nitrogen (P < 0.0001), with Pb exposure also associated with higher levels of MDA (P < 0.0001). Correlation analyses demonstrated significant associations between urinary Pb and Ni concentrations and various biomarkers related to DM and metabolic disorders. In conclusion, this study provides substantial evidence linking Pb and Ni exposure to the development of DM and metabolic disorders in a Pakistani population, emphasizing the need for strict regulations and preventive measures to reduce heavy metal contamination and safeguard public health. Future longitudinal studies and interventions are warranted to elucidate mechanistic links between heavy metal exposure and metabolic diseases.

Leveraging visible-near-infrared spectroscopy and machine learning to detect nickel contamination in soil: Addressing class imbalances for environmental management

Excessive concentrations of Ni in soil have many severe effects, negatively affecting human health and leading to disease, while also posing a threat to animals and plants. Although the dangers of high Ni concentrations have been widely recognized, rapid and large-scale tools for the identification of Ni contamination are still lacking. Visible-near-infrared (Vis-NIR) spectroscopy has been employed to rapidly identify Ni contamination; however, previous studies suffer from issues inherent to small datasets and the tendency to negate data imbalances. To address these issues, a large dataset comprising 18,675 soil samples was used to predict soil Ni contamination by combining Vis-NIR data with machine learning (ML). The data imbalance inherent to previous studies was addressed using two data sampling methods. To build a robust classification model for Ni contamination, four spectral preprocessing methods and four ML algorithms were compared. The optimal extreme gradient boosting model achieved recall, accuracy, area under the curve, and geometric mean scores of 0.8203, 0.8806, 0.9268, and 0.8508, respectively. Model predictions across the United States identified specific regions with high possibility of Ni contamination. Overall, the model developed in this study offers an improved accuracy in predicting soil Ni contamination at the continental scale, and can be used to prioritize further testing and guide policymaking.

Mitigating Ni and Cu ecotoxicity in the ecological restoration material and ornamental Primula forbesii Franch. with exogenous 24-epibrassinolide and melatonin

Nickel (Ni) and copper (Cu) contamination have become major threats to plant survival worldwide. 24-epibrassinolide (24-EBR) and melatonin (MT) have emerged as valuable treatments to alleviate heavy metal-induced phytotoxicity. However, plants have not fully demonstrated the potential mechanisms by which these two hormones act under Ni and Cu stress. Herein, this study investigated the impact of individual and combined application of 24-EBR and MT on the growth and physiological traits of Primula forbesii Franch. subjected to stress (200 μmol L–1 Ni and Cu). The experiments compared the effects of different mitigation treatments on heavy metal (HM) stress and the scientific basis and practical reference for using these exogenous substances to improve HM resistance of P. forbesii in polluted environments. Nickel and Cu stress significantly hindered leaf photosynthesis and nutrient uptake, reducing plant growth and gas exchange. However, 24-EBR, MT, and 24-EBR + MT treatments alleviated the growth inhibition caused by Ni and Cu stress, improved the growth indexes of P. forbesii, and increased the gas exchange parameters. Exogenous MT effectively alleviated Ni stress, and 24-EBR + MT significantly alleviated the toxic effects of Cu stress. Unlike HM stress, MT and 24-EBR + MT activated the antioxidant enzyme activity (by increasing superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), significantly reduced reactive oxygen species (ROS) accumulation, and regulated ascorbate and glutathione cycle (AsA-GSH) efficiency. Besides, the treatments enhanced the ability of P. forbesii to accumulate HMs, shielding plants from harm. These findings conclusively illustrate the capability of 24-EBR and MT to significantly bolster the tolerance of P. forbesii to Ni and Cu stress.

Physicochemical Analysis and Pollution Indices for Heavy Metal Assessment in Flooded and Non-flooded Soils of Obunagha, Bayelsa State, Nigeria

Soil samples from flood affected areas and non-affected areas of different farmlands in Obunagha, Bayelsa State, Nigeria; were collected for this study. The study was conducted to evaluate the physicochemical properties, and pollution indices of flooded and non-flooded farmlands to see if the flood had any effect in the fertility state of these soils. Atomic absorption spectroscopy (AAS) was used to identify and quantify the several heavy metals (Cd, Cr, Ni, and Zn) that were discovered in the collected soil samples. The findings indicated increased acidity since the pH of the soil varied between 4.8 and 5.7 in farmlands that were flooded and between 4.9 and 5.7 in farmlands that were not. In flooded areas, electrical conductivity ranged from 0.2x101 to 4x101 µS/cm, while in non-flooded areas, it was between 0.2x101 and 2x101 µS/cm. The cation exchange capacity in flooded farmlands was 0.16 to 0.24 meq/100 g, while in non-flooded farmlands it was 0.18 to 0.22 meq/100 g. Variations in metal contamination were found in different farming situations based on the contamination factor (CF) analysis. Chromium CF values ranged from 0.3 to 0.8 in both flooded and non-flooded farmlands, with certain non-flooded farmlands having slightly higher values. Cadmium contamination in flooded farmlands was much higher (25.5 to 43.7 CF) than in non-flooded farmlands (20.0 to 32.0 CF). Nickel contamination levels were from 0.7 to 1.1 in flooded farmlands and 0.5 to 0.8 in non-flooded farmlands, suggesting moderate pollution. Zinc contamination was consistently low throughout all circumstances, with CF values ranging from 0.2 to 0.4. According to the contamination factor average, Cd was followed by Ni, Cr, and Zn in decreasing order. The ecological pollution degree for the study area was low indicating no possible pollution by all the heavy metals. In conclusion, the study area is significantly contaminated with cadmium. Therefore, we urgently recommend monitoring the soil in the surrounding farmlands, particularly for cadmium, to prevent a potential environmental crisis.

Strength and functionalized borage biochar for effective elimination of nickel contamination: Insight into batch and dynamic flow mode treatment applications

A silica gel-modified borage biochar (BB@Si) was first produced and used as a binding agent for potentially hazardous Ni2+ ions in aqueous systems. The recommended biochar was more effective in eliminating Ni2+ than pristine biochar (BB). Its maximum qm could reach up to 1.39 × 10−3 mol/g at 30 °C, and sorption isotherms showed that the Langmuir model could more accurately define its sorption behavior. The Dubinin-Radushkevich isotherm also revealed that the average sorption energy ranged from 11.00 to 11.14 kJ/mol. Zeta potential tests, SEM images, and FT-IR scans confirmed the interactions between BB@Si and Ni2+ ions. Dynamic flow treatment studies showed high uptake effectiveness when the flow rate and amount of BB@Si were suitable. Nickel desorption yield of around 80% from BB@Si was noted with 0.01 M HCl. The BB@Si column's breakthrough and exhausted points were identified to be 45 and 352 min, respectively. Its maximum exhaustion capacity value was determined to be 52.73 mg/g. Ni2+ removal from the actual wastewater sample exceeded 75%. The resulting outcomes imply the immense potential of employing BB@Si in the treatment of Ni2+– contaminated aqueous systems.

Development of a Whole-Cell System Based on the Use of Genetically Modified Protoplasts to Detect Nickel Ions in Food Matrices.

Heavy metals are dangerous contaminants that constitute a threat to human health because they persist in soils and are easily transferred into the food chain, causing damage to human health. Among heavy metals, nickel appears to be one of the most dangerous, being responsible for different disorders. Public health protection requires nickel detection in the environment and food chains. Biosensors represent simple, rapid, and sensitive methods for detecting nickel contamination. In this paper, we report on the setting up a whole-cell-based system, in which protoplasts, obtained from Nicotiana tabacum leaves, were used as transducers to detect the presence of heavy metal ions and, in particular, nickel ions. Protoplasts were genetically modified with a plasmid containing the Green Fluorescent Protein reporter gene (GFP) under control of the promoter region of a sunflower gene coding for a small Heat Shock Protein (HSP). Using this device, the presence of heavy metal ions was detected. Thus, the possibility of using this whole-cell system as a novel tool to detect the presence of nickel ions in food matrices was assessed.

Study of spectral lines behaviour with a double pulse 1064–1064 nm laser-induced breakdown spectroscopy system at the direct analysis of algae on the filter

The nickel and zinc contamination of algae on a cellulose filter was studied with double pulse 1064–1064 nm laser-induced breakdown spectroscopy (LIBS). Samples of the green alga Desmodesmus subspicatus were contaminated with zinc and nickel. The surface concentrations on the filter calculated from the reference Inductively Coupled Plasma Mass Spectrometry analysis were 25 and 64 ng cm−2 for nickel and zinc respectively. The algae are resting on the filter after drying and a double adhesive tape was used to fix the sample on the microscopic glass. During optimization method a compromise of 23–30 mJ pulse energies were set for maintaining a detectable or highest signal intensity of the analyte and not destroying the filter. Best conditions for maximum analyte signal and minimum deviation between the spectral behaviour of the analyte and the compared line of Na I, K I, Mg I, Mg II, Mn I, Mn II, Ca I, Ca II, and C I was 700 ns gate delay and 0 s interpulse delay. The deviation was rather more influenced with the signal-to-noise ratio of the analyte line than the closeness of the upper-level energies of the compared lines. The filter without algae showed systematically lower electron number density and total emissivity by units of percents than the filter with algae.

Radiation defects as probes for the copper and nickel contamination during the chemomechanical polishing of Si wafers

Radiation defects as probes for the copper and nickel contamination during the chemomechanical polishing of Si wafers

Features of immunological indicators in children with allergy modified by nickel contamination of biomedia and polymorphism of CPOX rs1131857 detoxification gene

Introduction. The impact of unfavourable environmental chemical factors on the human immune system predetermines the conditions for the formation of pathological conditions associated with allergies.&#x0D; The purpose of the study. To study the features of immunological indicator parameters in children with allergies modified by contamination of biological media with nickel and polymorphism of the detoxification CPOX rs1131857 gene.&#x0D; Materials and methods. A study was conducted one hundred eighty children suffering from various forms of allergies, permanently residing in the zone of the Far North (121 of them — under conditions of aerogenic exposure to nickel aerosols, and 59 children — in a “conditionally clean” territory). The subject of the study was biological media (blood). The change in the content of specific IgE to nickel was determined by an allergosorbent test with an enzyme label. The study of cell differentiation clusters included the use of flow cytometry (CD3+, CD19+, CD3+CD4+, CD3+CD8+, CD16+CD56+). Polymorphism of the CPOX (rs1131857) gene was studied by real-time polymerase chain reaction (PCR).&#x0D; Results. The analysis of the immune and genetic status of children with various manifestations of allergic pathology revealed cellular immunodeficiency (CD3+ CD4+, a decrease in the immunoregulatory index), the development of processes of hypersensitivity to chemical technogenic haptens (IgE to nickel), as well as an increased frequency of occurrence of heterozygous AC polymorphism of the second detoxification gene. phase CPOX rs1131857, verified by significant parameters of inheritance models (OR = 2.83; 95% CI: 1.14–7.01; &#x0D; p &lt; 0.05).&#x0D; Limitations. The present study is not exposed to the adult population, does not consume the population, and does not consume, except in the Far North.&#x0D; Conclusion. A feature of the course of allergic pathology in the children’s population of the Arctic, modified by contamination of biomedia with nickel and polymorphism of the detoxification CPOX rs1131857 gene, will be an increased frequency and duration of recurrence of allergopathology due to the addition of viral (decrease in cellular immunity) and hapten (nickel) components.

Heavy metals mitigation and growth promoting effect of endophytic Agrococcus terreus (MW 979614) in maize plants under zinc and nickel contaminated soil.

Heavy metals such as iron, copper, manganese, cobalt, silver, zinc, nickel, and arsenic have accumulated in soils for a long time due to the dumping of industrial waste and sewage. Various techniques have been adapted to overcome metal toxicity in agricultural land but utilizing a biological application using potential microorganisms in heavy metals contaminated soil may be a successful approach to decontaminate heavy metals soil. Therefore, the current study aimed to isolate endophytic bacteria from a medicinal plant (Viburnum grandiflorum) and to investigate the growth-promoting and heavy metal detoxification potential of the isolated endophytic bacteria Agrococus tereus (GenBank accession number MW 979614) under nickel and zinc contamination. Zinc sulfate and nickel sulfate solutions were prepared at the rate of 100 mg/kg and 50 mg/kg in sterilized distilled water. The experiment was conducted using a completely random design (CRD) with three replicates for each treatment. Inoculation of seeds with A. tereus significantly increased the plant growth, nutrient uptake, and defense system. Treatment T4 (inoculated seeds), T5 (inoculated seeds + Zn100 mg/kg), and T6 (inoculated seeds + Ni 100 mg/kg) were effective, but T5 (inoculated seeds + Zn100 mg/kg) was the most pronounced and increased shoot length, root length, leaf width, plant height, fresh weight, moisture content, and proline by 49%, 38%, 89%, 31%, 113%, and 146%, respectively. Moreover the antioxidant enzymes peroxidase and super oxidase dismutase were accelerated by 211 and 68% in contaminated soil when plants were inoculated by A. tereus respectively. Similarly the inoculation of A. tereus also enhanced maize plants' absorption of Cu, Mn, Ni, Na, Cr, Fe, Ca, Mg, and K significantly. Results of the findings concluded that 100 mg/kg of Zn and Ni were toxic to maize growth, but seed inoculation with A. tereus helped the plants significantly in reducing zinc and nickel stress. The A. tereus strain may be employed as a potential strain for the detoxification of heavy metals.

Histological and ionomics assessment to elucidate tolerance mechanisms of nickel-tolerant and sensitive cultivars of bread wheat (Triticum aestivum L.)

Recent literature has raised concerns over crop safety due to nickel (Ni) contamination of irrigation water and agricultural soil in Pakistan. Consequently, wheat crop has suffered in terms of nutrient disbalance and yield reduction. Therefore, it is important to screen tolerant wheat cultivars against Ni toxicity with the ability to accumulate low concentration in grains. In this regard, two wheat cultivars (SKD-1 and Borlaug-16) were exposed to Ni stress (100 mg/L) in a pot experiment for 21 days. In the present study, trace elements (As, Cr, Cu, Cd, Mn, Hg, Ni, Pb, and Zn) and mineral nutrients (Ca, Fe, K, Mg, Na, and P) were tested by ICP-OES. To understand tolerance mechanisms, wheat tissues were tested for morphological parameters, anatomical alteration, oxidative stress, and antioxidant capacity. The translocation of Ni was higher in SKD-1 (0.62) compared to Borlaug-16 (0.45) due to low Ni accumulation in roots of Borlaug-16. In the roots of Borlaug-16, trace elements (Cr, Cu, Mn, Pb, and Zn) were comparatively higher than SKD-1. On the contrary, nutrients (Ca, Fe, Mg, Na, and P) were higher in leaves of SKD-1. Under Ni stress, the root anatomy of Borlaug-16 exhibited a marked increase in the cellular thickness of the cortex by 130.38% and stele by 46.2%. Conversely, the bundle sheath cell thickness rose by 68.36% in the SKD-1. In terms of leaf anatomy, Borlaug-16 showed enhanced thickness in the xylem by 13.01% and bundle sheath cells by 84.95%. Meanwhile, the upper epidermis and phloem of SKD-1 registered thickness increases of 21.80% and 24.47% under Ni stress. Oxidative stress (MDA and H2O2) was comparatively highly induced in SKD-1 tissues compared to Borlaug-16. On the other hand, antioxidants (SOD, CAT, and APX) were comparatively higher in root and leaf tissues of Borlaug-16. The lower Ni uptake, less cellular damage, and high antioxidant capacity of Borlaug-16 makes it more tolerant to Ni stress. Such findings will pave the way towards sustainable crop production.

Nickel-induced oxidative stress causes cell death in testicles: implications for male infertility.

Aligarh region is well known for its lock industry. This lock industry utilises nickel for electroplating. There have been informal reports of infertility in men and women living near the lock industry. We analysed field water samples to investigate this link, and the results showed considerable nickel contamination. To further validate our results, we exposed male rats to relevant nickel levels in drinking water. This experimental exposure resulted in abnormal sperm morphology, decline in sperm count, significant change in activities of antioxidant enzymes, pronounced oxidative stress in the rat spermatocytes and decrease in serum testosterone level, as well as damage in the hypothalamus and pituitary (in all cases, the changes were most significant at the highest concentration used i.e 2.5 mg/l). The breeding experiments showed decline in live birth rate, while pups did not survive post birth in cages where males were given 2 and 2.5 mg/l concentrations of nickel in drinking water prior to mating. Our data strongly indicate a link between industrial nickel exposure and male infertility.

Soil nickel contamination levels entail changes in the bacterial communities associated to the rhizosphere and endosphere of Odontarrhena chalcidica

Soil nickel contamination levels entail changes in the bacterial communities associated to the rhizosphere and endosphere of Odontarrhena chalcidica

Concentration of Trace Elements in Cryoconites of Mountain and Polar Regions of the World

The surface of mountain glaciers is a place of accumulation of various biogenic organomineral and mineral compounds. As a result of intensive mass deglaciation of glaciers due to climate change and anthropogenic activity, this material can significantly affect the transformation of the landscape in the periglacial zone. Thus, this work considers the contamination of the surface of the Arctic, Antarctic, and Caucasian glaciers by priority pollutants. Atomic absorption spectroscopy was used to analyze trace elements (Cu, Zn, Ni, Cd, Pb) from cryoconite deposits. It was revealed that the cryoconite dust on the Ray-Iz glacier (Polar Urals) has a high level of nickel contamination, which comes to the glacier from local rock materials as a result of their weathering. The lowest concentrations of trace elements are found in one of the Arctic plots located at Mushketov and Aldegonda glaciers, the Caucasus, and the Antarctic, which is due to their relatively low content in the composition of rocks and the relatively low contribution of long-range transport of matter to the polar regions. Contamination of moraine sediments in the periglacial zone can make a significant contribution to the formation of the soil cover of these territories, the pollution of water bodies near the glacier, as well as affect the quality of life of the people living in the immediate vicinity of the mountain areas.

Exogenous abscisic acid fine-tunes heavy metal accumulation and plant’s antioxidant defence mechanism to optimize crop performance and secondary metabolite production in Trigonella foenum-graecum L. under nickel stress

Nickel (Ni) contamination of farming soil has become currently a recurring global menace to agriculture crop productivity. The purpose of the present study was to investigate the putative contributions of abscisic acid (ABA) to extemporize Ni tolerance in Trigonella foenum-graecum L. (fenugreek) plants. The outcomes of this study exposed that exogenous supplementation of ABA at 10, 20, 40 and 80 µM considerably enhanced the growth and physiological attributes of fenugreek under 80 mg Ni kg−1 soil, however, 40 µM of ABA exhibited the best results under normal and Ni-stressed conditions. ABA-mediated Ni tolerance was marked by reductions in Ni accumulation and consequent lowering of reactive oxygen species (ROS) like hydrogen peroxide and superoxide radicals. Contrarily, NO (nitric oxide) level increased in response to ABA application under Ni stress conditions, accompanied by promoted antioxidant activities through improved levels of secondary metabolites, proline, and perked-up ROS-detoxification enzymes activities. Exogenous ABA at 40 µM concentration applied to Ni-exposed plants (80 mg Ni kg−1 soil) improved the total content of alkaloids, phenolics, flavonoids and tannins by 14.3%, 10.2%, 15.4% and 7.0%, respectively, over Ni-stressed plants alone. Additionally, seed trigonelline content imparting several pharmacological actions to the fenugreek plant exhibited a remarkable escalation upto 3.6 and 2.6 mg g−1 DW under ‘40 µM ABA’ and ‘40 µM ABA + 80 mg Ni kg−1 soil’ treatments, respectively. The findings of the study suggest that ABA plays a key role in enhancing the overall performance of the fenugreek crop under excessive Ni stress.

Determination of conditioning factors for mapping nickel contamination susceptibility in groundwater in KanchanaburiProvince, Thailand, using random forest and maximum entropy.

Groundwater pollution from nickel (Ni) has been a severe concern in Kanchanaburi Province, Thailand. Recent assessments revealed that theNi concentration in groundwater, particularly in urban areas, often exceeded the permissible limit. The challenge for groundwater agencies is therefore to delineate regions with high susceptibility to Ni contamination. In this study, a novel modeling approach was applied to a dataset of 117 groundwater samples collected from Kanchanaburi Province between April and July 2021. Twenty site-specific initial variables were considered as influencing factors to Ni contamination. The Random Forest (RF) algorithm with Recursive Feature Elimination (RFE) function was used to select the fourteen most influencing variables. These variables were then used as input features to train a ME model to delineate the Ni contamination susceptibility at a high confidence (Area Under the Curve (AUC) validation value of 0.845). Ten input variables of the altitude, geology, land use, slope, soil type, distance to industrial areas, distance to mining areas, electric conductivity, oxidation-reduction potential, and groundwater depth were discovered in the most explaining the variation of spatial Ni contamination at very high (95.47 km2) and high (86.65 km2) susceptibility. This studydevises the novel machine learning approach to identify the conditioning factors and map Ni contamination susceptibility in the groundwater, which provides a baseline dataset and reliable methods for the development of a sustainable groundwater management strategy.

Thermal modulation of mitochondrial function is affected by environmental nickel in rainbow trout (Oncorhynchus mykiss)

In this study, we investigated the combined effects of temperature and nickel (Ni) contamination on liver mitochondria electron transport system (ETS) enzymes, citrate synthase (CS), phospholipid fatty acid composition and lipid peroxidation in rainbow trout (Oncorhynchus mykiss). Juvenile trout were acclimated for two weeks to two different temperatures (5˚C and 15˚C) and exposed to nickel (Ni; 520 μg/L) for three weeks. Using ratios of ETS enzymes and CS activities, our data suggest that Ni and an elevated temperature acted synergistically to induce a higher capacity for reduction status of the ETS. The response of phospholipid fatty acid profiles to thermal variation was also altered under nickel exposure. In control conditions, the proportion of saturated fatty acids (SFA) was higher at 15˚C than at 5˚C, while the opposite was observed for monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). However, in nickel contaminated fish, the proportion of SFA was higher at 5˚C than at 15˚C, while PUFA and MUFA followed the opposite direction. A higher PUFA ratio is associated with higher vulnerability to lipid peroxidation. Thiobarbituric Acid Reactive Substances (TBARS) content was higher when the PUFA were in higher proportions, except for Ni-exposed, warm-acclimated fish, in which we reported the lowest level of TBARS but the highest proportion of PUFA. We suspect that the interaction of nickel and temperature on lipid peroxidation is due to their synergistic effects on aerobic energy metabolism, as supported by the decrease in the activity of complex IV of the ETS enzyme activity in those fish, or on antioxidant enzymes and pathways. Overall, our study demonstrates that Ni exposure in heat-challenged fish can lead to the remodelling of the mitochondrial phenotype and potentially stimulate alternative antioxidant mechanisms.

Biomarkers as ecological indices in monitoring the status of market fish

BackgroundEnvironmental contamination has become a major concern over the past few decades, drawing the attention of numerous researchers from both developed and developing nations. The aquatic system serves as the primary sink for the disposal of garbage, which has a negative impact on the aquatic environment and biota. The reality is that heavy metals cannot be totally removed from the ecosystem because they can bioaccumulate and grow in strength as they move up the food chain. Particularly heavy metals can build up in the tissues of aquatic animals, and as a result, tissue concentrations of heavy metals may be harmful to both human and animal health. Our study aimed to elucidate the possible use of biomarkers in monitoring and assessing the heavy metals contaminants among fresh water fish.ResultsFrom the present study, we conclude that glutathione peroxidase can be used as the bioindicator for nickel and iron contamination. Ultimately, these studies focus on measuring levels of pollution that may induce irreversible ecological changes to aquatic ecosystems. Till now the level of toxicity was moderate, and it was progressing toward the danger. Efforts can be made to control the activities that release pollutants unnaturally into the environment from both public and government so that the clean and clear environment can be maintained.ConclusionsThe work concludes that a multiparameter analysis is needed to assess and monitor the ecological status of the aquatic environment.

Synergistic mitigation of nickel toxicity in pepper (Capsicum annuum) by nitric oxide and thiourea via regulation of nitrogen metabolism and subcellular nickel distribution.

Nickel (Ni) contamination hinders plant growth and yield. Nitric oxide (NO) and thiourea (Thi) aid plant recovery from heavy metal damage, but their combined effects on pepper (Capsicum annuum ) plant tolerance to Ni stress need more study. Sodium nitroprusside (0.1mM, SNP) and 400mgL-1 Thi, alone and combined, were studied for their impact on pepper growth under Ni toxicity. Ni stress reduces chlorophyll, PSII efficiency and leaf water and sugar content. However, SNP and Thi alleviate these effects by increasing leaf water, proline and sugar content. It also increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase. Nickel stress lowered nitrogen assimilation enzymes (nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase and glutamate dehydrogenase) and protein content, but increased nitrate, ammonium and amino acid content. SNP and Thi enhanced nitrogen assimilation, increased protein content and improved pepper plant growth and physiological functions during Ni stress. The combined treatment reduced Ni accumulation, increased Ni in leaf cell walls and potentially in root vacuoles, and decreased Ni concentration in cell organelles. It effectively mitigated Ni toxicity to vital organelles, surpassing the effects of SNP or Thi use alone. This study provides valuable insights for addressing heavy metal contamination in agricultural soils and offers potential strategies for sustainable and eco-friendly farming practices.