Nickel Toxicity Research Articles

To Assess the Toxicity of Nickel on Above and Below Ground Biomass of Raphanus Sativus Variety Pusa Chetki in Natural Conditions (Pot Culture Experiments)

To Assess the Toxicity of Nickel on Above and Below Ground Biomass of Raphanus Sativus Variety Pusa Chetki in Natural Conditions (Pot Culture Experiments)

Co-application of silicon and biochar affected anatomical and biochemical properties of corn leaf (Zea mays L.) under soil nickel toxicity

Soil pollution with heavy metals is a threat to crop production. Practically, application of silicon (Si) with biochar can be a cost-effective approach to immobilize metals in contaminated soils. Investigation of the anatomical and biochemical changes of corn leaf is important for describing the mechanisms of Si and biochar soil application in alleviating the negative effects of nickel (Ni) toxicity. A factorial pot experiment was conducted to investigate the effect of Si (0, 250 and 500 mg Si kg-1 soil) in combination with rice husk biochar (RHB) or sheep manure biochar (SMB) prepared at two pyrolysis temperatures (300 and 500 °C) on anatomical and biochemical properties of corn leaves in a Ni-polluted soil. The length, width, area and weight of third-leaf, and metaxylem and protoxylem of midrib improved by application of Si250 with RHB more than SMB. At Si250, RHB300 and RHB500 improved the stomatal area by 31.7 and 27.7% compared to control (without biochar), respectively. The leaf membrane stability index was increased by increasing Si application level and reached 69% in RHB300. In contrast to total chlorophyll, the highest carotenoid content, catalase and peroxidase was obtained by control (without Si and biochar) followed by SMB. At Si250, the highest relative water content (RWC) was observed in RHB300 by 34.8% increase. Also, RHB300 had the highest total dry matter, with increases of 82.2, 120.0 and 83.1% at Si0, Si250 and Si500, respectively. By increasing the Si level and biochar application, the shoot Ni decreased between 42.1 to 133.3%. Combined application of Si250 with RHB300 resulted in the highest dry matter through improving the leaf dimensions, metaxylem and protoxylem areas of midrib, membrane stability index, total chlorophyll, and RWC, while Ni uptake was reduced.

Morpho-physiological response to micronutrient deficiencies and nickel addition of passion fruit plants

Ultrastructural changes and visual symptoms resulting from nutritional disorders involving boron, manganese, iron, zinc, copper, molybdenum, and nickel depend on the species of the plant, and are unknown in passion fruit plants (Passiflora edulis Sims). A hydroponic experiment evaluated the symptoms of nickel addition and micronutrient deficiency in passion fruit seedlings “BRS Gigante Amarelo” and determined the micronutrient contents in leaf and root tissue, root development, ultrastructural changes (leaf tissue deformations) and dry matter accumulation when visual symptoms were observed. Results showed that the order of manifestation of deficiencies was Fe > Mn > Zn > Cu > Mo > B. Nickel toxicity appeared 40 days after the experiment was started, presenting chlorosis in the new leaves followed by general yellowing and some white parts. Boron omission of resulted in deformations in the leaf limbus and loss of apical dominance, showing deformation of the growth points. Mn omission caused reduction of growth and generalized chlorosis of young leaves with a thick reticulum. Iron omission of resulted in internerval chlorosis with a fine lattice appearance. Omission of zinc and copper resulted in deformation and elongation of the leaves, reducing height and root development. Molybdenum omission caused chlorosis in the older leaves, which was observed to spread over time. Iron was the nutrient that most reflected symptoms of deficiency by the formation of root hairs. The findings of this research suggest that the knowledgement of plant micronutrients status permits an understanding of the physiological responses of passion fruit plants to crop fertilization.

The bifunctional transcription factor NAC32 modulates nickel toxicity responses through repression of root-nickel compartmentalization and activation of auxin biosynthesis

Nickel (Ni) is an important micronutrient, but excess Ni is toxic to many plant species. Currently, relatively little is known about the genetic basis of the plant responses to Ni toxicity. Here, we demonstrate that NAC32 transcription factor functions as a core genetic hub to regulate the Ni toxicity responses in Arabidopsis. NAC32 negatively regulates root-Ni concentration through the IREG2 (IRON REGULATED2) encoding a transporter. NAC32 also induces local auxin biosynthesis in the root-apex transition zone by upregulating YUCCA 7 (YUC7)/8/9 expression, which results in a local enhancement of auxin signaling in root tips, especially under Ni toxicity, thereby impaired primary root growth. By analyses of various combinations of nac32 and ireg2 mutants, as well as nac32 and yuc7/8/9 triple mutants, including high-order quadruple mutant, we demonstrated that NAC32 negatively regulates Ni stress tolerance by acting upstream of IREG2 and YUC7/8/9 to modulate their function in Ni toxicity responses. ChIPqPCR, EMSA (electrophoretic mobility shift assay) and transient dual-LUC reporter assays showed that NAC32 transcriptionally represses IREG2 expression but activates YUC7/8/9 expression by directly binding to their promoters. Our work demonstrates that NAC32 coordinates Ni compartmentation and developmental plasticity in roots, providing a conceptual framework for understanding Ni toxicity responses in plants.

Sensitivity of Alabama Freshwater Gastropod Species to Nickel Exposure.

Snails are effective bioindicators due to their prolific distribution, high level of endemism, and capacity to accumulate contaminants. Freshwater snails have unique ecological niches which are imperiled by land-use change and the introduction of hazardous chemicals. To assess how environmental alterations affect gastropods, lab-based studies are needed to characterize the toxicity of specific stressors. This can help guide policy decisions and remediation efforts. The aim of this research was to characterize acute toxicity of nickel (Ni) on endemic snails (Somatogyrus georgianus [Walker, 1904], Elimia cahawbensis [Lea, 1861], and Elimia spp.) and measure the accumulation of Ni and mineral elements including calcium (Ca), magnesium, potassium, and sodium (Na). Snails were exposed to six concentrations (25-800 µg/L) of Ni for 96 h. Among the studied snail species, E. cahawbensis was the most sensitive to Ni, with the lowest lethal concentration where 50% of the organisms died (LC50) at 88.88 µg/L Ni after 96 h. The LC50 at 96 h for S. georgianus was 167.78 µg/L Ni, and 393.13 μg/L Ni for Elimia spp. Except for Elimia spp., mortality of the other two snail species corresponded to the whole-body uptake of Ni. Nickel exposure also influenced Ca and Na uptake for Elimia spp. All three endemic species are potential candidate species for evaluating localized effects of human activities, and the present study provides a first step in characterizing how snails would be affected by environmental alterations. More research could further characterize potential effects of other human stressors on these endemic snail species. Future research into subindividual responses and routes of exposure can further elucidate variations in species sensitivity. Environ Toxicol Chem 2024;00:1-11. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

P02-01 Comparison of nickel toxicity in Air-Liquid Interface models of human and rat bronchial epithelial cells

P02-01 Comparison of nickel toxicity in Air-Liquid Interface models of human and rat bronchial epithelial cells

Alleviation of nickel toxicity by molybdenum in wheat

Alleviation of nickel toxicity by molybdenum in wheat

Transcriptomics pave the way into mechanisms of cobalt and nickel toxicity: Nrf2-mediated cellular responses in liver carcinoma cells

Cobalt (Co) and Nickel (Ni) are used nowadays in various industrial applications like lithium-ion batteries, raising concerns about their environmental release and public health threats. Both metals are potentially carcinogenic and may cause neurological and cardiovascular dysfunctions, though underlying toxicity mechanisms have to be further elucidated. This study employs untargeted transcriptomics to analyze downstream cellular effects of individual and combined Co and Ni toxicity in human liver carcinoma cells (HepG2). The results reveal a synergistic effect of Co and Ni, leading to significantly higher number of differentially expressed genes (DEGs) compared to individual exposure. There was a clear enrichment of Nrf2 regulated genes linked to pathways such as glycolysis, iron and glutathione metabolism, and sphingolipid metabolism, confirmed by targeted analysis. Co and Ni exposure alone and combined caused nuclear Nrf2 translocation, while only combined exposure significantly affects iron and glutathione metabolism, evidenced by upregulation of HMOX-1 and iron storage protein FTL. Both metals impact sphingolipid metabolism, increasing dihydroceramide levels and decreasing ceramides, sphingosine and lactosylceramides, along with diacylglycerol accumulation. By combining transcriptomics and analytical methods, this study provides valuable insights into molecular mechanisms of Co and Ni toxicity, paving the way for further understanding of metal stress.

Ocean acidification alleviated nickel toxicity to a marine copepod under multigenerational scenarios but at a cost with a loss of transcriptome plasticity during recovery

Marine ecosystem has been experiencing multiple stressors caused by anthropogenic activities, including ocean acidification (OA) and nickel (Ni) pollution. Here, we examined the individual/combined effects of OA (pCO2 1000 μatm) and Ni (6 μg/L) exposure on a marine copepod Tigriopus japonicus for six generations (F1-F6), followed by one-generation recovery (F7) in clean seawater. Ni accumulation and several important phenotypic traits were measured in each generation. To explore within-generation response and transgenerational plasticity, we analyzed the transcriptome profile for the copepods of F6 and F7. The results showed that Ni exposure compromised the development, reproduction and survival of copepods during F1-F6, but its toxicity effects were alleviated by OA. Thus, under OA and Ni combined exposure, due to their antagonistic interaction, the disruption of Ca2+ homeostasis, and the inhibition of calcium signaling pathway and oxytocin signaling pathway were not found. However, as a cost of acclimatization/adaption potential to long-term OA and Ni combined exposure, there was a loss of transcriptome plasticity during recovery, which limited the resilience of copepods to previously begin environments. Overall, our work fosters a comprehensive understanding of within- and transgenerational effects of climatic stressor and metal pollution on marine biota.

Unveiling the potential of A. fabrum and γ-aminobutyric acid for mitigation of nickel toxicity in fenugreek

Nickel (Ni) is a heavy metal that adversely affects the growth of different crops by inducing oxidative stress and nutrient imbalance. The role of rhizobacteria (RB) is vital to resolve this issue. They can promote root growth and facilitate the uptake of water and nutrients, resulting in better crop growth. On the other hand, γ-aminobutyric acid (GABA) can maintain the osmotic balance and scavenge the reactive oxygen species under stress conditions. However, the combined effect of GABA and RB has not been thoroughly explored to alleviate Ni toxicity, especially in fenugreek plants. Therefore, in the current pot study, four treatments, i.e., control, A. fabrum (RB), 0.40 mM GABA, and 0.40 mM GABA + RB, were applied under 0Ni and 80 mg Ni/kg soil (80Ni) stress. Results showed that RB + 0.40 mM GABA caused significant improvements in shoot length (~ 13%), shoot fresh weight (~ 47%), shoot dry weight (~ 47%), root length (~ 13%), root fresh weight (~ 60%), and root dry weight (~ 15%) over control under 80 Ni toxicity. A significant enhancement in total chlorophyll (~ 14%), photosynthetic rate (~ 17%), stomatal CO2 concentration (~ 19%), leaves and roots N (~ 10 and ~ 37%), P (~ 18 and ~ 7%) and K (~ 11 and ~ 30%) concentrations, while a decrease in Ni (~ 83 and ~ 49%) concentration also confirmed the effectiveness of RB + 0.40 mM GABA than control under 80Ni. In conclusion, fabrum + 0.40 mM GABA can potentially alleviate the Ni toxicity in fenugreek plants. The implications of these findings extend to agricultural practices, environmental remediation efforts, nutritional security, and ecological impact. Further research is recommended to elucidate the underlying mechanisms, assess long-term effects, and determine the practical feasibility of using A. fabrum + 0.40GABA to improve growth in different crops under Ni toxicity.

Physiological and molecular bases of the nickel toxicity responses in tomato

Nickel (Ni), a component of urease, is a micronutrient essential for plant growth and development, but excess Ni is toxic to plants. Tomato (Solanum lycopersicum L.) is one of the important vegetables worldwide. Excessive use of fertilizers and pesticides led to Ni contamination in agricultural soils, thus reducing yield and quality of tomatoes. However, the molecular regulatory mechanisms of Ni toxicity responses in tomato plants have largely not been elucidated. Here, we investigated the molecular mechanisms underlying the Ni toxicity response in tomato plants by physio-biochemical, transcriptomic and molecular regulatory network analyses. Ni toxicity repressed photosynthesis, induced the formation of brush-like lateral roots and interfered with micronutrient accumulation in tomato seedlings. Ni toxicity also induced reactive oxygen species accumulation and oxidative stress responses in plants. Furthermore, Ni toxicity reduced the phytohormone concentrations, including auxin, cytokinin and gibberellic acid, thereby retarding plant growth. Transcriptome analysis revealed that Ni toxicity altered the expression of genes involved in carbon/nitrogen metabolism pathways. Taken together, these results provide a theoretical basis for identifying key genes that could reduce excess Ni accumulation in tomato plants and are helpful for ensuring food safety and sustainable agricultural development.

Biocompatible antibiotic-coupled nickel-titanium nanoparticles as a potential coating material for biomedical devices

The challenges facing metallic implants for reconstructive surgery include the leaching of toxic metal ions, a mismatch in elastic modulus between the implant and the treated tissue, and the risk of infection. These problems can be addressed by passivating the metal surface with an organic substrate and incorporating antibiotic molecules. Nitinol (NiTi), a nickel-titanium alloy, is used in devices for biomedical applications due to its shape memory and superelasticity. However, unmodified NiTi carries a risk of localized nickel toxicity and inadequately supports angiogenesis or neuroregeneration due to limited cell adhesion, poor biomineralization, and little antibacterial activity. To address these challenges, NiTi nanoparticles were modified using self-assembled phosphonic acid monolayers and functionalized with the antibiotics ceftriaxone and vancomycin via the formation of an amide. Surface modifications were monitored to confirm that phosphonic acid modifications were present on NiTi nanoparticles and 100% of the samples formed ordered films. Modifications were stable for more than a year. Elemental composition showed the presence of nickel, titanium, and phosphorus (1.9% for each sample) after surface modifications. Dynamic light scattering analysis suggested some agglomeration in solution. However, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed a particle size distribution of <100 nm, the even distribution of nanoparticles on coverslips, and elemental composition before and after cell culture. B35 neuroblastoma cells exhibited no inhibition of survival and extended neurites of approximately 100 μm in total length when cultured on coverslips coated with only poly-l-lysine or with phosphonic acid-modified NiTi, indicating high biocompatibility. The ability to support neural cell growth and differentiation makes modified NiTi nanoparticles a promising coating for surfaces in metallic bone and nerve implants. NiTi nanoparticles functionalized with ceftriaxone inhibited Escherichia coli and Serratia marcescens (SM6) at doses of 375 and 750 μg whereas the growth of Bacillus subtilis was inhibited by a dose of only 37.5 μg. NiTi-vancomycin was effective against B. subtilis at all doses even after mammalian cell culture. These are common bacteria associated with infected implants, further supporting the potential use of functionalized NiTi in coating reconstructive implants.

Decrypting Molecular Mechanisms Involved in Counteracting Copper and Nickel Toxicity in Jack Pine (Pinus banksiana) Based on Transcriptomic Analysis.

The remediation of copper and nickel-afflicted sites is challenged by the different physiological effects imposed by each metal on a given plant system. Pinus banksiana is resilient against copper and nickel, providing an opportunity to build a valuable resource to investigate the responding gene expression toward each metal. The objectives of this study were to (1) extend the analysis of the Pinus banksiana transcriptome exposed to nickel and copper, (2) assess the differential gene expression in nickel-resistant compared to copper-resistant genotypes, and (3) identify mechanisms specific to each metal. The Illumina platform was used to sequence RNA that was extracted from seedlings treated with each of the metals. There were 449 differentially expressed genes (DEGs) between copper-resistant genotypes (RGs) and nickel-resistant genotypes (RGs) at a high stringency cut-off, indicating a distinct pattern of gene expression toward each metal. For biological processes, 19.8% of DEGs were associated with the DNA metabolic process, followed by the response to stress (13.15%) and the response to chemicals (8.59%). For metabolic function, 27.9% of DEGs were associated with nuclease activity, followed by nucleotide binding (27.64%) and kinase activity (10.16%). Overall, 21.49% of DEGs were localized to the plasma membrane, followed by the cytosol (16.26%) and chloroplast (12.43%). Annotation of the top upregulated genes in copper RG compared to nickel RG identified genes and mechanisms that were specific to copper and not to nickel. NtPDR, AtHIPP10, and YSL1 were identified as genes associated with copper resistance. Various genes related to cell wall metabolism were identified, and they included genes encoding for HCT, CslE6, MPG, and polygalacturonase. Annotation of the top downregulated genes in copper RG compared to nickel RG revealed genes and mechanisms that were specific to nickel and not copper. Various regulatory and signaling-related genes associated with the stress response were identified. They included UGT, TIFY, ACC, dirigent protein, peroxidase, and glyoxyalase I. Additional research is needed to determine the specific functions of signaling and stress response mechanisms in nickel-resistant plants.

Evaluation of the Risk from Potentially Toxic Elements (PTEs) in Italy’s Most Consumed Processed Fish Products

In a balanced diet, regular fish consumption provides positive outcomes for human health. On the other hand, the seafood supply chain faces a significant food safety risk due to the presence of potentially toxic elements (PTEs). In the present study, to assess the risk for Italian consumers, the concentrations of five PTEs, namely lead, chromium, cadmium, mercury, nickel, and aluminum, were determined in the three most consumed preserved fish in Italy: tuna (Thunnus albacares, Katsuwonus pelamis), mackerel (Scomber scombrus) and anchovy (Engraulis encrasicolus). Samples were collected from the national market, and the instrumental analysis was performed by inductively coupled plasma mass spectrometry (ICP-MS). The analyzed PTEs were found in all the species that were investigated. However, after considering the target hazard quotient (THQ) and the hazard index (HI), it was observed that the three fish preserves did not pose any risk of chronic toxicity for the average consumer, even at the highest concentrations detected. However, for significant consumers, mercury detected in tuna samples represented almost 90% of the tolerable weekly intake (TWI) reported by the European Food Safety Authority (EFSA), representing a matter of concern for consumers, particularly regarding developmental neurotoxicity, whose HI exceeded 111%. The acute toxicity of nickel was also considered for significant consumers at the highest concentration detected, and the margin of exposure (MOE) calculated was above 7000, much higher than the value of 30 indicated by EFSA. Due to the lack of data on non-professional carcinogenicity or human intake through foods with low cancer risk, this toxicity was not considered in the analysis of PTEs.

Defensive Influence of Methanol Fraction and Crude Extract of Cocoplum (Chrysobalanus icaco L.) on Nickel Toxicity in Male Wistar Rats

Defensive Influence of Methanol Fraction and Crude Extract of Cocoplum (Chrysobalanus icaco L.) on Nickel Toxicity in Male Wistar Rats

Correction to ‘Exogenously applied sodium nitroprusside alleviates nickel toxicity in maize by regulating antioxidant activities and defense‐related gene expression’

Correction to ‘Exogenously applied sodium nitroprusside alleviates nickel toxicity in maize by regulating antioxidant activities and defense‐related gene expression’

Nickel toxicity mitigation by supplementation of acetylcholine in wheat: Growth, photosynthetic and antioxidant activities

Influence of exogenous treatment of acetylcholine (ACh; 5 and 10 µM) was studied on the growth, photosynthesis and nitrate reductase activity in wheat under nickel (500 µM Ni) stress. Plant height, fresh and dry weight of shoot showed a decline of 36%, 23% and 40% respectively while as increased by 35%, 44% and 47% due to 10 µM ACh over control. Treatment of ACh, at both concentrations, alleviated the decline with obvious effects at higher (10 µM) concentrations. Treatment of ACh resulted in increased content of total chlorophylls, carotenoids and photosynthesis, intercellular carbon dioxide, transpiration and PSII activity, which were however significantly reduced by Ni stress. Exogenous application of ACh alleviated the Ni stress mediated decline in the activity of nitrate reductase. Wheat plants treated with Ni showed increased production of hydrogen peroxide resulting in increased lipid peroxidation and electrolyte leakage, however treatment of ACh reduced these parameters significantly reflecting in alleviation of oxidative damage. Activity of antioxidant enzymes assayed (SOD, CAT, APX, DHAR and GR) and the content of ascorbic acid and reduced glutathione increased significantly in ACh treated plants under normal and Ni stress. Activities of SOD, CAT, APX, DHAR and GR was increased by 162%, 108%, 70%, 107% and 87% respectively in Ni + 10 µM ACh treated plants. In addition, the content of phenols and flavonoids increased due to application of ACh. Content of nitrogen, potassium and calcium increased due to ACh and also alleviated the decline induced due to Ni stress while as the content of Ni was reduced in plants treated with ACh.

Electrospinning of polylactic acid fibers reinforced with Ti3C2 for the removal of nickel ions from wastewater

Nickel ions play a crucial role as an essential micronutrient in both human beings and plants. However, the introduction and application of nickel ions augmented with industrialization, outpacing the expertise to access these materials beyond the planetary boundaries, causing nickel toxicity. Thus, the adsorptive removal of Ni2+ is earning ubiquitous significance attributed to the undesirable consequences on the ecosystem. The conceptualization of fabricating a sustainable material system, exterminating the prevailing challenges, thereby truncating the impact on the environment, and eradicating nickel ions from effluents was always a matter of substantial concern. Herein, we have fabricated PLA nano-microfibers via electrospinning technology with various Ti3C2 loading – 0.5, 1, and 3 wt%, introducing more porosity to the system to understand the applicability of these fibrous systems for Ni2+ removal. Incorporating Ti3C2Tx into the PLA matrix helps to fabricate a water-stable system further by increasing the adsorption capacity of PLA to 37.92 mg/g with 0.5 wt% Ti3C2Tx addition. The addition of Ti3C2Tx to the PLA matrix system and the surface morphology of the fabricated nanofiber composite were validated using FT-IR and SEM analysis, respectively. The biodegradable nature of the system was also explored under naturally mimicked conditions using cow dung slurry, where the 0.5 wt% loaded system demonstrated 12 % degradation within 30 days within the slurry. The induced biodegradability of the electrospun fibers, 3–17 % within 33 days, introduces an ideal and easily retrievable system for Ni2+ removal, eradicating potential hazardous effects on the ecosystem.

Alleviating effects of exogenous melatonin on nickel toxicity in two pepper genotypes

The excessive accumulation of nickel (Ni) poses a significant threat to global agricultural productivity. In recent years, it has become clear that melatonin (ME) may play a significant role in protecting plants against heavy metal toxicity. This current study investigates the influence of exogenous ME on mitigating the adverse effects of Ni toxicity in pepper plants. The present results revealed that Ni toxicity significantly hindered pepper seedling growth, damaged the leaf photosynthetic system, impaired pigment concentration, and increased phenolic content. In contrast, ME supplementation efficiently restored seedling growth, protected the photosynthetic system, and further increased the phenolic concentration in pepper leaves. In addition, Ni toxicity considerably increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) production and increased antioxidant enzymes [SOD (superoxide dismutase), CAT (catalase), POD (peroxidase), GR (glutathione reductase), APX (ascorbate peroxidase), and GST (glutathione S-transferase)] activity in pepper leaves and roots. Conversely, ME inhibited MDA and H2O2 accumulation and further increased the antioxidant enzyme activity in pepper leaves and roots. Furthermore, ME application restricted Ni accumulation from root to shoot. Collectively, the ME has shown the ability to mitigate the adverse effects of Ni toxicity in pepper plants. The findings of this study will contribute to the understanding and mitigation of the adverse impacts of Ni-induced stress on the growth and development of plants.

Survival potential and assessment of deformities in embryo and larvae of Chinese carps (Hypophthalmichthys molitrix and Ctenopharyngodon idella) under acute exposure of cadmium and nickel

ABSTRACT The effects of cadmium (Cd) and nickel (Ni) toxicity on embryonic and larval development of Hypophthalmichthys molitrix and Ctenopharyngodon idella was determined. Different concentrations (0.1, 0.3, and 0.5 mg/l) of Cd and Ni were administered in separate trials to the fish after spawning to 168 h post-hatching (hph) period. Cd was more toxic to the embryos of both fish, as highest embryonic mortality (%) of H. molitrix and C. idella was observed. However, Ni was found to be more toxic to the larvae of H. molitrix and C. Idella with highest larval mortality at 168 hph. However, Ni was found to be more toxic to the larvae of H. molitrix and C. idella with highest larval mortality at 168 hph. The study found a significant effect of heavy metal and metal concentration for causing deformities in H. molitrix. However, in C. idella only the effect of metal concentration on fish deformities was significant. Furthermore, Ni was found to cause more deformities as compared to Cd in H. molitrix. While Cd was found to cause more deformities as compared to Ni in C. idella. In conclusion, the study suggests that Cd and Ni may cause serious deformities in fish.