Non-essential Heavy Metals Research Articles

Comparative assessment of the heavy metal phytoextraction potential of vegetables from agricultural soils: A field experiment

A field study was established to determine the phytoextraction potential of six vegetable species, namely Amaranthus viridis L., Basella alba L., Brassica chinensis var. Parachinensis, Brassica rapa L., Capsicum frutescens L., and Ocimum tenuiflorum L.. These edible plants were selected for their short growth cycles and high biomass production, which are some traits for efficient phytoremediation. Following acid digestion of the soil and vegetable samples using the USEPA 3050B acid digestion method, the extracts were analyzed for Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn using ICP-OES. Results in soil samples showed that the concentrations of both beneficial and essential heavy metals, and non-essential heavy metals are below the WHO, USEPA, and CCME soil quality guidelines. Al is one of the highest concentrations found in the soil samples but it tends to accumulate in the root part of all vegetable species compared to the aboveground parts. In general, B. rapa L. accumulated the highest level of Cd (0.4 mg/kg) and Pb (5.71 mg/kg), while B. alba L. accumulated the highest Cr (2.62 mg/kg) in all plant parts. The findings in this study indicated that Co, Cu, Fe, Mn and Zn were mostly accumulated in leaves of A. viridis L. (Co, Cu, Fe, Mn and Zn), B. alba L. (Co, Fe and Mn), B. chinensis (Mn and Zn) and O. tenuiflorum L. (Mn), and roots of C. frutescens L. (Co, Cu, Fe and Mn), B. alba L. (Co, Cu and Zn), A. viridis L. and B. chinensis (Cu and Fe) and B. rapa L. (Fe). Cr, Pb and Ni were significantly greater in B. alba L. (Cr) And B. rapa L. (Ni and Pb) roots. MTF >1 was observed in the roots of all species for Co, Cd, Zn, and Ni. BTC values varied between the different vegetable species with A. viridis L. having the greatest heavy metal mobility between its plant parts and the best heavy metal phytoextraction potential among other species. The PCA biplots showed that heavy metals were partitioned differently between various plant parts of the vegetable species and can be explained by the first two components (PC1 and PC2) which were associated with the root and/or leaf parts for most vegetable species.

Thyroid-Disrupting Effects of Cadmium and Mercury in Zebrafish Embryos/Larvae

Cadmium (Cd2+) and mercury (Hg2+) are two kinds of non-essential heavy metals. Cd2+ and Hg2+ can cause thyroid disruption, but very few researchers have investigated the thyroid-disrupting effects of these metals on fish, specifically during their early developmental transition stage from embryos to larvae. In this study, wild-type zebrafish embryos were exposed to varying concentrations (contents) of Cd2+ (0, 10, 100, and 1000 μg/L) and Hg2+ (0, 0.1, 1, and 10 μg/L) for 120 h. Thereafter, the thyroid hormone contents and transcriptional changes in the genes, including thyroid stimulating hormone-β (tshβ), thyroglobulin (tg), sodium-iodide symporter (nis), thyroid peroxidase (tpo), transthyretin (ttr), thyroid hormone receptor-α and -β (thrα, thrβ), types I and II iodothyronine deiodinase (dio1, dio2), and uridine diphosphate glucuronosyltransferase 1 family a, b (ugt1ab) associated with the hypothalamic-pituitary-thyroid (HPT) axis were measured. Results showed that zebrafish embryos/larvae malformation rates were significantly higher in the Cd2+ and Hg2+ groups. A significant increase in the thyroxine (T4) concentration and a decrease in the triiodothyronine (T3) concentration were observed in the Cd2+-exposed zebrafish embryos/larvae. On the other hand, the T4 and T3 concentrations were observed to be significantly increased after Hg2+ exposure. Additionally, changes were noted in the expression patterns of the HPT axis-linked genes after Cd2+ and Hg2+ exposure. Based on the results of the principal component analysis (PCA), it was concluded that Cd2+ exposure significantly affected the thyroid endocrine system at a concentration of 100 μg/L, whereas Hg2+ exposure led to a thyroid disruption at a low concentration of 0.1 μg/L. Thus, this study demonstrated that exposure to Cd2+ and Hg2+ metal ions induced developmental toxicity and led to thyroid disruption in zebrafish embryos/larvae.

The Effect of Ca-Bentonite Aplication on Cadmium Uptake and Shoot Dry Matter of Bread Wheat

Cadmium(Cd) is a non-essential heavy metal that is highly toxic even at very low concentrations. Although Cd is a non-essential trace metal, when reached to high levels in agricultural soils, it can be easily absorbed by plants. Cadmium accumulation in wheat (Triticum aestivum L.) and its subsequent transfer to food chain is an important problem worldwide. Bentonite is a material essentially composed by montmorillonite and related clay minerals of the smectite group. The purpose of this study was to investigate the effects of bentonite (0, 3, 6 and 12%) application on Cd uptake of bread wheat growing in high Cd (0, 5 and 10 mg/kg soil) application. Plants were grown under greenhouse conditions acid soil. The experiment was conducted randomized block design with three replicates. The results revealed that shoot dry weight of bread was significantly increased with increasing doses of bentonite applications. While the dry weight of shoot without bentonite application was 480 mg/plant, it increased approximately 2 fold with 12% bentonite application. Cadmium concentration with the bentonite of control application decreased 4 times from 20.74 ppm to 5.07 ppm with application of 12% bentonite. The results show that Cd toxicity in the shoot was alleviated by bentonite treatment.

Fibronectin 1 as a Key Gene in the Genesis and Progression of Cadmium-Related Bladder Cancer.

Exposure to cadmium (Cd), a non-essential heavy metal, leads to the malignant transformation of urothelial cells and promotes bladder cancer (BC) development, but the mechanisms are unclear. Therefore, we aimed to explore the possible molecules associated with Cd-related BC. By analyzing and mining biological big data in public databases, we screened genes associated with the malignant transformation of uroepithelial cells caused by Cd and further screened the key gene associated with BC prognosis from these genes. The possible roles of the key gene in BC progression were then further explored through biological big data analysis and cellular experiments. Data mining yielded a total of 387 malignant transformation-related genes, which were enriched in multiple cancer-related signaling pathways, such as cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, and Jak-STAT signaling pathway. Further screening identified Fibronectin 1 (FN1) as the key gene. High expression of FN1 was associated with the advanced pathologic stage, T stage, N stage, and M stage and predicted an unfavorable outcome in BC patients. FN1 expression was positively associated with the infiltration of several types of immune cells, particularly tumor-associated macrophages and cancer-associated fibroblasts. Overexpression of FN1 could be detected in Cd-treated urothelial cells and BC cell lines. Interestingly, silencing of FN1 impaired the proliferation and invasive capacity of BC cells. In conclusion, the present study provides new insight into the mechanism of Cd-related BC. FN1 might be a prognostic marker and therapeutic target for BC. Future studies are needed to confirm these results.

Kadmiyum Stres Koşullarında Farklı Priming Uygulamalarında Çeltiğin Çimlenme ve Fide Gelişimi

The non-essential heavy metal cadmium (Cd) prevents rice seed germination and seedling growth when it is present in micromolar concentrations. To mitigate the effects of Cd toxicity on rice, seed priming, a pre-germinated seedling approach, may improve seed and seedling performance. In 2019, an experiment was conducted in Turkey to evaluate seed germination and seedling growth of rice. The experiment was comprised of five concentrations of Cd stress (0, 50, 100, 200 and 400 ppm) on three rice cultivars (Osmancık 97, Halilbey, and Kızıltan) and three seed priming techniques such as hydropriming, priming using 2% KNO3 (potassium nitrate), and priming using 100 mg/L salicylic acid. The complete randomized design was arranged to be conducted with three replications in this investigation. The findings demonstrated that each Cd dose had detrimental effects on seed germination and seedling growth in all rice varieties. All varieties showed different reactions to priming treatments. Hydropriming showed the most positive impact on germination, while priming with KNO3 exhibited negative effects for all rice varieties. The Cd content of plant roots were higher than the shoots. It was observed that the lowest Cd content was detected in the shoots and roots of plants which were pre-treated with SA as compared to other priming applications. More than 50 ppm of cadmium was harmful because it lowered morphological features. However, seed hydropriming partially corrected these effects. For Cd stress resistance, the rice genotype Kızıltan continued to outperform the other cultivars studied.

Assessment of Some Heavy Metals and Their Relationship with Oxidative Stress and Immunological Parameters in Aquatic Animal Species.

Heavy metal accumulation changes the immune system and leads to oxidative damage in aquatic animals. The present study evaluated the correlation between heavy metal accumulation, with immunological and oxidative stress parameters, in various species in the aquatic environment of Western Iran. Fresh samples included fish (trout and carp) and shrimp obtained from Sanandaj aquaculture. After blood sampling and serum isolation for immunological study, meat sections of these animals were used to measure heavy metal concentrations to determine the oxidative stress and immunological parameters. The highest concentrations of Pb (0.82 ± 0.10), As (0.53 ± 0.18), Hg (0.47 ± 0.08), and Zn (28.77 ± 1.88) (µg/g) were found in trout, while the lowest accumulation of heavy metals except for Cd (0.24 ± 0.11) and Se (1.57 ± 0.42) (µg/g) were observed in shrimp. The antioxidant enzymes glutathione peroxidase (GPx) (1.89 ± 0.13) and superoxide dismutase (SOD) (1.96 ± 0.62) U/mg showed the highest concentrations in shrimp and lowest in the trout. Significant negative correlations were found between these enzymes with As and Pb in trout and carp. A significant positive correlation was determined between Se and Zn with GPx and a negative correlation with malondialdehyde (MDA) in shrimp. Immunological biomarkers indicated the concentrations of IL-6, TNF-α, and IFN-Ƴ were higher in fish than in shrimp, and the lowest IgM level was obtained in Shrimp. Increased Pb and Cd showed a significant relationship with increased IL-6 and TNF-α in trout compared to shrimp and carp.An increase in As and Se concentration beyound maximum permissible limits (MPL) were recorded in fish andshrimp, while a Zn level less than MPL was recorded.The target hazard quotients (THQ) and target cancer risk (TR) values of non-essential heavy metals were obtained under acceptable ranges. We suggest reducing the As and Pb content under aquaculture farms and increase in the amount of Zn through diets to keep healthy immunological and physiological conditions for aquatic species in the west of Iran.

The Prevalence of Vitamin and Mineral Deficiencies and High Levels of Non-Essential Heavy Metals in Saudi Arabian Adults.

Although the micronutrient status of a population is of high national priority, as it critically impacts public health, limited data is available for quantifying the micronutrient status in Saudi Arabia. We aimed to provide comprehensive, epidemiological, descriptive data regarding micronutrient levels in Saudi adults. This cross-sectional study included 3432 adults aged ≥18 years (mean age, 37.7 ± 11.7 years; women, 51.2%) across all 13 Saudi administrative regions (March 2019-November 2021). Laboratory data for 14 micronutrients (8 vitamins, 4 minerals, and 2 nonessential heavy metals) were characterized using descriptive analysis. Vitamin D deficiency (64.3%) was the most prevalent, followed by vitamin B2 (44.9%) and A (9.6%) deficiencies. Among minerals, iron deficiency was the most prevalent (23.2%), followed by zinc (15.3%) and copper (8.7%) deficiencies. Most Saudi adults exhibited normal arsenic (99.7%) and mercury (99.9%) levels. Men exhibited significantly higher vitamin B2, B9, and D deficiencies than women, while women exhibited higher vitamin A, B12, iron, and zinc deficiencies than men. Younger adults demonstrated a significantly higher prevalence of vitamin D and iron deficiencies, whereas older adults exhibited a higher prevalence of vitamin B1 and magnesium deficiencies. As micronutrient deficiencies are a public health concern, health policies and programs need to be developed and implemented to address them.

HUBUNGAN ANTARA JARAK SUMUR GALI TERHADAP KADAR KADMIUM (CD), TIMBAL (PB) DAN MERKURI (HG) AIR SUMUR GALI DI SEKITAR TPA TROKETON KABUPATEN KLATEN

The buffer zone and limited cultivation zone of the TPA Troketon are used as vegetable fields, where in these zones can be polluted by leachate containing non-essential metals (Hg, Pb, Cd, etc.). Non-essential heavy metals are toxic when consumed. Non-essential heavy metals are absorbed into plant tissues, so water for watering vegetable crops must be free from heavy metal content. However, farmers use water from wells dug around the TPA to water the vegetable crops in their fields. Based on the description above, the authors conducted research on the relationship between the distance of the dug wells and the levels of Cadmium, Lead and Mercury in the dug well water around the TPA Troketon.This study aims to determine the effect of the distance dug wells on the TPA with the metal content of Cadmium, Lead and Mercury in the dug well water which is located in a straight line with the TPA and the IPL output flow. This research was conducted by checking the levels of Cadmium, Lead and Mercury in the laboratory and then the results were compared with the distance of the well to the landfill by analysis using SPSS.The results of the analysis of the relationship between well distance and lead levels in dug well water show a negative correlation with a coefficient value of -0.565 or have a relationship but not significant and the effect of distance with lead levels is 35.6%, while Mercury metal in dug well water shows correlation with coefficient value of 0.512 or having a relationship but not significant and the effect of distance with mercury levels of 26.2%. As for the metal content of Cadmium, the tool cannot read in more detail, so a correlation analysis is not carried out. The levels of heavy metals analyzed in well water are still below the permissible threshold.

Metabolic effects of long-term cadmium exposure: an overview.

Cadmium (Cd) is a toxic non-essential heavy metal. Chronic low Cd exposure (CLCE) has been associated with distinct pathologies in many organ systems, including liver and kidney damage, osteoporosis, carcinogenicity, or reproductive toxicity. Currently, about 10% of the global population is at risk of CLCE. It is urgent to find robust and effective biomarkers for early diagnosis of Cd exposure and treatment. Metabolomics is a high-throughput method based on mass spectrometry to study the dynamic changes in a series of endogenous small molecular metabolites (typically < 1000Da) of tissues, cells, or biofluids. It can reflect the rich and complex biochemical changes in the body after exposure to heavy metals, which may be useful in screening biomarkers to monitor exposure to environmental pollutants and/or predict disease risk. Therefore, this review focuses on the changes in metabolic profiles of humans and rodents under long-term Cd exposure from the perspective of metabolomics. Furthermore, the relationship between the disturbance of metabolic pathways and the toxic mechanism of Cd is discussed. All these information will facilitate the development of reliable metabolic biomarkers for early detection and diagnosis of Cd-related diseases.

Autophagy induces mTOR-dependent glucose uptake and mTOR-independent lactate utilization in cadmium-treated A549 cells

Cadmium (Cd) is a non-essential heavy metal with many harmful effects, especially tumorigenesis. Previously we established that autophagy-dependent increasing of glycolysis played an important role in Cd-induced cell growth and migration of A549 and HELF cells. In this study, we found Cd could induce autophagy and mTOR in A549 cells, HELF cells and in lung tissues of BALB/c mice. More interestingly, Cd-induced elevation of mTOR was autophagy-dependent and autophagy-induced cell growth and glycolysis was mTOR-dependent. However, in A549 cells, besides the above mTOR-dependent pathway, Cd-induced autophagy could directly induce PKM2 and LDHA independent of mTOR. Further study showed that only in A549 cells could autophagy other than mTOR enable Cd to increase MCT1 expression and MCT1 was involved in autophagy-induced PKM2 and LDHA. Sodium lactate added in the culture medium promoted Cd-induced cell growth of A549 cells, while had no effect on HELF cells. Finally, the effect of autophagy/MCT1/PKM2 pathway on lactate utilization to facilitate Cd-induced A549 cell growth was determined. Above all, we concluded that in HELF cells, autophagy induced mTOR-dependent glycolysis in which GLUT1 and HKII was elevated to promote glucose intake to accelerate cell growth. Whereas, in A549 cells, besides the above pathway to use glucose, autophagy could induce an mTOR-independent glycolysis pathway in which lactate could be used as fuel through autophagy-MCT1-PKM2 to escape glucose deficiency.

Non-essential heavy metals and protective effects of selenium against mercury toxicity in endangered Australian sea lion (Neophoca cinerea) pups with hookworm disease

The endangered Australian sea lion, Neophoca cinerea, faces ongoing population decline. Identification of key threats to N. cinerea population recovery, including disease and pollutants, is an objective of the species’ recovery plan. Previous studies have identified Uncinaria sanguinis, an intestinal nematode, as a significant cause of disease and mortality in N. cinerea pups. Given the impact of heavy metals on the immune response, investigation of these pollutants is critical. To this end, the concentrations of arsenic (As), total mercury (Hg), cadmium (Cd), chromium (Cr), lead (Pb) and selenium (Se) were determined in blood collected from N. cinerea pups sampled during the 2017/18, 2019 and 2020/21 breeding seasons at Seal Bay Conservation Park, South Australia.Significant differences (p < 0.05) in Hg, As, Cr, and Se concentrations and molar ratio of Se:Hg were seen between breeding seasons. Pup age, maternal parity and inter-individual foraging behaviour were considered factors driving these differences. The concentrations of Hg (357, 198 and 241 µg/L) and As (225, 834 and 608 µg/L) were high in 2017/18, 2019 and 2020/21 respectively with Hg concentrations in the blood of N. cinerea pups above toxicological thresholds reported for marine mammals. The concentration of Se (1332, 647, 763 µg/L) and molar ratio of Se:Hg (9.47, 7.98 and 6.82) were low compared to other pinniped pups, indicating potential vulnerability of pups to the toxic effects of Hg. Significant (p < 0.05) negative associations for Pb and Cd with several red blood cell parameters suggest they could be exacerbating the anaemia caused by hookworm disease. Temporal (age-related) changes in element concentrations were also seen, such that pup age needs to be considered when interpreting bioaccumulation patterns.Further investigation of the role of elevated heavy metal concentrations on N. cinerea pup health, disease and development is recommended, particularly with respect to immunological impacts.

Transcriptome Analysis Reveals the Stress Tolerance to and Accumulation Mechanisms of Cadmium in Paspalum vaginatum Swartz.

Cadmium (Cd) is a non-essential heavy metal and high concentrations in plants causes toxicity of their edible parts and acts as a carcinogen to humans and animals. Paspalum vaginatum is widely cultivating as turfgrass due to its higher abiotic stress tolerance ability. However, there is no clear evidence to elucidate the mechanism for heavy metal tolerance, including Cd. In this study, an RNA sequencing technique was employed to investigate the key genes associated with Cd stress tolerance and accumulation in P. vaginatum. The results revealed that antioxidant enzyme activities catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glutathione S-transferase GST) were significantly higher at 24 h than in other treatments. A total of 6820 (4457/2363, up-/down-regulated), 14,038 (9894/4144, up-/down-regulated) and 17,327 (7956/9371, up-/down-regulated) differentially expressed genes (DEGs) between the Cd1 vs. Cd0, Cd4 vs. Cd0, and Cd24 vs. Cd0, respectively, were identified. The GO analysis and the KEGG pathway enrichment analysis showed that DEGs participated in many significant pathways in response to Cd stress. The response to abiotic stimulus, the metal transport mechanism, glutathione metabolism, and the consistency of transcription factor activity were among the most enriched pathways. The validation of gene expression by qRT-PCR results showed that heavy metal transporters and signaling response genes were significantly enriched with increasing sampling intervals, presenting consistency to the transcriptome data. Furthermore, over-expression of PvSnRK2.7 can positively regulate Cd-tolerance in Arabidopsis. In conclusion, our results provided a novel molecular mechanism of the Cd stress tolerance of P. vaginatum and will lay the foundation for target breeding of Cd tolerance in turfgrass.

Green Synthesis of Silver Nanoparticles Using Artemisia vulgaris Extract and Its Application toward Catalytic and Metal-Sensing Activity

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Artemisia vulgaris-mediated silver nanoparticles (AgNP) without any modification in an aqueous solution. The UV–vis spectroscopy showed a characteristic SPR band of Ag0 at 418 nm, indicating the formation of AgNPs. The AgNPs were crystalline, with an average size of 7 nm, as calculated from the XRD data. The SEM images revealed the spherical and polycrystalline AgNPs within the agglomerated form. The FTIR spectra elucidated the functional group of the extract attached with the Ag0. The broad, strong peak at 3632 cm−1 indicated the involvement of the -OH group of compounds of extract in reducing silver ions. The peak of EDX spectra around 3 keV confirmed the silver in the nanostructure. A colorimetric method was employed for the heavy metal sensing in the aqueous medium without modification of AgNPs suspension. The obtained AgNPs were found to be selective and highly sensitive toward Hg2+ ions. The AgNPs suspension turned colorless after adding 380 µL of 1 mM Hg2+. The synthesized AgNPs showed the catalytic activity on reduction of 4-nitrophenol in the presence of NaBH4 within 8 min with a rate constant of 1.21 × 10−2 s−1. The outcome of these findings suggests that the application of Artemisia vulgaris influenced AgNPs for metal sensing and green catalysis.

Yeast Inhibitive Assay for Anionic Heavy Metals: A review

One of the most common types of pollution that has a negative impact on the biotic community in aquatic habitats is heavy metal poisoning of the water. Both essential and non-essential heavy metals can be toxic to living things if their concentrations are too high for their bioavailability. Although the toxicity of heavy metals, and especially anionic metal ions, is better known than that of cationic metal ions, it is just as toxic, if not more so. The focus of this review is on the usefulness of eukaryotic organisms like yeast, Saccharomyces cerevisiae, for toxicity assessment because they can be easily maintained and developed in controlled circumstances, thereby avoiding variability issues that arise when employing more complex organisms. Recent research has shown that the majority of cellular MTT reduction occurs outside of the mitochondrial inner membrane, and that this reduction is dependent on NADH and NADPH but is resistant to respiratory chain inhibitors.

Genome sequencing of biocontrol strain Bacillus amyloliquefaciens Bam1 and further analysis of its heavy metal resistance mechanism

Plant growth-promoting rhizobacteria (PGPR) or Biocontrol strains inevitably encounter heavy metal excess stress during the product’s processing and application. Bacillus amyloliquefaciens Bam1 was a potential biocontrol strain with strong heavy metal resistant ability. To understand its heavy metal resistance mechanism, the complete genome of Bam1 had been sequenced, and the comparative genomic analysis of Bam1 and FZB42, an industrialized PGPR and biocontrol strain with relatively lower heavy metal tolerance, was conducted. The comparative genomic analysis of Bam1 and the other nine B. amyloliquefaciens strains as well as one Bacillus velezensis (genetically and physiologically very close to B. amyloliquefaciens) was also performed. Our results showed that the complete genome size of Bam1 was 3.95 Mb, 4219 coding sequences were predicted, and it possessed the highest number of unique genes among the eleven analyzed strains. Nine genes related to heavy metal resistance were detected within the twelve DNA islands of Bam1, while only two of them were detected within the seventeen DNA islands of FZB42. When compared with B. amyloliquefaciens type strain DSM7, Bam1 lacked contig L, whereas FZB42 lacked contig D and I, as well as just possessed contig B with a very small size. Our results could also deduce that Bam1 promoted its essential heavy metal resistance mainly by decreasing the import and increasing the export of heavy metals with the corresponding homeostasis systems, which are regulated by different metalloregulators. While Bam1 promoted its non-essential heavy metal resistance mainly by the activation of some specific or non-specific exporters responding to different heavy metals. The variation of the genes related to heavy metal resistance and the other differences of the genomes, including the different number and arrangement of contigs, as well as the number of the heavy metal resistant genes in Prophages and Genomic islands, led to the significant different resistance of Bam1 and FZB42 to heavy metals.Graphical

Comparative transcriptome analysis of broccoli seedlings under different Cd exposure levels revealed possible pathways involved in hormesis

As a non-essential heavy metal, Cd has long been considered to cause plant damage and reduce crop productivity. Recently, accumulating studies have shown that low-level Cd shows beneficial effects on plants, called hormesis. However, the mechanism of low-level Cd triggered hormesis is largely unknown. In this study, we found that Cd showed a hormesis effect on broccoli seedlings. The comparative transcriptome analysis of broccoli seedlings under low-level and high-level Cd showed that the plants responded distinctively to different concentrations of Cd exposure. KEGG analysis suggested that plant hormone signaling and secondary metabolism, especially glucosinolate homeostasis, were important under both low and high-level Cd treatment. Interestingly, ethylene signaling pathway, auxin signaling pathway, glucosinolate degradation, and glutathione redox showed opposite responses to low and high-level Cd. Low-level Cd inhibited while high-level Cd promoted ethylene signaling. Low-level Cd enhanced auxin biosynthesis while high-level repressed auxin biosynthesis. Glucosinolate degradation was enhanced by low-level Cd and inhibited by high-level Cd. As an important indicator of cell redox state, the ratio of reduced glutathione to oxidized glutathione (GSH/GSSG) increased under low-level and decreased under high-level Cd. Since the above biological processes play important roles in both growth and Cd detoxification, their opposite response to different levels of Cd indicated their possible involvement in hormesis. The potential functions of these processes in hormesis are discussed. Our study shed a light on the underlying mechanisms of the Cd-mediated hormesis effect.

The health risk for consumers under heavy metal scenarios: Reduce bioaccumulation of Cd in estuary mud crab (Scylla paramamosain) through the antagonism of Se

Heavy metal pollution has gained increasing attention over past years, and notably, cadmium (Cd) is a non-essential heavy metal that can be toxic to human and wildlife. Furthermore, selenium (Se) is a component of the selenoproteins and influences the toxicity of Cd in different organisms, and protect organisms as a kind of heavy metal antagonist. This study exposed mud crab to 5.0 mg/L Cd for 28 days, and investigated whether different concentrations (0.1, 0.2, 0.3 mg/kg) of selenite (Na2SeO3) or selenomethionine (SeMet) affect the bioaccumulation of Cd, serum biochemical index, antioxidant and stress-response genes of S. paramamosain. The results showed that the Cd concentration in Cd group was significantly higher than the organic or inorganic Se group. Serum biochemical index demonstrated that Se might relieve the damage or dysfunction of hepatopancreas caused by both Cd accumulation and toxicity. Furthermore, Se improved CAT, GPx T-AOC and SOD activity, and decreased MDA concentrations and the lipid peroxidation levels, antagonistic to Cd. Then, this study analyzed the expression of 26 stress-related genes, the results indicated that the inorganic and organic Se might reduce the damage of cell and the toxicity of heavy metals in the hepatopancreas after Cd exposure. Therefore, this study indicated that Se might alleviate Cd toxicity via the different antioxidative mechanisms, and increased the understanding of environmental toxins on estuary crustaceans.

Phytochemical: a treatment option for heavy metal induced neurotoxicity.

Heavy metals are known to be carcinogenic, mutagenic, and teratogenic. Some heavy metals are necessary while present in the growing medium in moderate concentrations known to be essential heavy metals as they required for the body functioning as a nutrient. But there are some unwanted metals and are also toxic to the environment and create a harmful impact on the body, which termed to be non-essential heavy metals. Upon exposure, the heavy metals decrease the major antioxidants of cells and enzymes with the thiol group and affect cell division, proliferation, and apoptosis. It interacts with the DNA repair mechanism and initiates the production of reactive oxygen species (ROS). It subsequently binds to the mitochondria and may inhibit respiratory and oxidative phosphorylation in even low concentrations. This mechanism leads to damage antioxidant repair mechanism of neuronal cells and turns into neurotoxicity. Now, phytochemicals have led to good practices in the health system. Phytochemicals that are present in the fruits and herbs can preserve upon free radical damage. Thus, this review paper summarized various phytochemicals which can be utilized as a treatment option to reverse the effect of the toxicity caused by the ingestion of heavy metals in our body through various environmental or lifestyles ways.

Fish Parasites and Heavy Metals Relationship in Wild and Cultivated Fish as Potential Health Risk Assessment in Egypt

Despite wide studies of biomonitoring aquatic environment through dynamics of host–parasite interaction, bio-indicators to track the influence and accumulation of heavy metals on fish are still few. The present study sheds light on the relation between fish parasites and heavy metals as it threatens fish’s health and, as a consequence, that of humans after fish consumption. Samples of Nile tilapia (Oreochromis niloticus) were collected in Burullus Lake, a wild fish source, and from a private fish farm in Kafr El-Sheikh Governorate, in Egypt. They were exposed to various pollutants associated with anthropogenic activities to determine the levels of accumulation of Fe, Zn, and Cu, along with the top three most toxic metals (As, Cd, and Pb) in water and fish tissues of gills, intestine, liver, and muscles in both wild and farmedO. niloticus. The results showed the order of abundance: Fe &amp;lt; Zn &amp;lt; Pb &amp;lt; Cu &amp;lt; As &amp;lt; Cd. In waters of both farmed and wild fish, there was a significant negative relation between parasite prevalence and heavy metals, including Zn, Pb, and As. Also, there was a significant positive relation between parasite prevalence with Cu while no significant relation was found with Fe and Cd. Heavy metal content was significantly higher (p&amp;gt; 0.05) in non-infected than infected farmed and wildO. niloticus. In addition, a significantly decreased concentration (p&amp;gt; 0.05) of essential heavy metal was recorded in wild fish compared to farmed specimens, while non-essential heavy metal was significantly higher (p&amp;gt; 0.05) in wild compared to farmed fish. Bioaccumulation factors (BAF) of different organs ofO. niloticuswere ranked in ascending order: Liver &amp;gt; Gills &amp;gt; Intestine &amp;gt; Muscles. In general, the risk assessment showed safe human consumption of farmed and wild fish under the reported environmental conditions in this study. Moreover, the parasite's presence can be adopted as a surrogate indicator to estimate the potential impact of heavy metal pollution and accumulation.

Potential of Using Land Snails (Eobania vermiculata and Monacha obstructa) for Monitoring the Essential and Non-Essential Heavy Metal in Ismailia City, Egypt

ABSTRACT To assess the role of land snails as the monitor for heavy metal pollution and to determine the species-specific accumulation of metals in Eobania vermiculata and Monacha obstructa. A field survey of heavy metals was carried out in two different areas in Ismailia city, Egypt. The study was conducted to evaluate the essential and non-essential heavy metals in the tissue of land snails and compared them with their levels in shell and soil to find out which can accumulate more biotic or abiotic?. The heavy metals concentrations of essential and non-essential heavy metals of soft tissues of two snail species and sediment collected from Ring Road, Ismailia, in Egypt had the highest levels of heavy metals as compared to another site in most seasons except in spring season levels of essential (Cu, Mn, Zn, Co, Mo, Ca and Mg) and non-essential metals (Cd, Pb, Al, and B) were higher in El-Balah Road than Ring Road. Therefore, El Balah Road was less polluted as compared with Ring Road which was more crowded with cars. The ranges of essential metals in samples of the soft tissue of E. vermiculata along with the two sites, Ring Road and El Balah Road, were higher for Ca and Mg than other essential metals. However, Al as a non-essential metal in soft tissue samples of E. vermiculata for the two sites was the most common metal. Moreover, the levels of the same metals were elevated in M. obstructa along with the two sites. The results indicated that E. vermiculata and M. obstructa soft tissues do not reflect the environmental bioavailability of heavy metals as the shells do. Therefore, the shells of E. vermiculata and M. obstructa could be considered as a more useful bioindicator for Co, Cu, Mn, Zn, Mo, Ca, Mg, and Pb.