Non-essential Heavy Metals Research Articles

Unravelling the interplay between Harmattan wind and baroreflex functions: implications on environmental health and cardiovascular pathophysiology

Harmattan is a season characterized by dust, cold, and sub-humid trade winds in Sub-Saharan countries. It’s similar to meteorological phenomena like Asian dust storms, Santa Ana winds, Australian bushfires, and Saharan dust in the Caribbean. It causes profound changes in the cardiorespiratory system in apparently healthy individuals and increases the risk of hospitalization in susceptible individuals. Exposure to these extreme conditions has been associated with alterations in autonomic function and baroreceptor sensitivity thus resulting in dysregulation of blood pressure control mechanisms. Baroreceptors are critical regulators of hemodynamics and cardiovascular function. They play a vital role in the short-term responses to blood pressure perturbation and are essential for acute restoration of blood pressure following cold exposure. Harmattan wind contains a barrage of chemicals, dust, and particulate matters depending on industrialization, natural and human activities. Particulate matter from Harmattan dust can trigger systemic inflammation and oxidative stress, exacerbating endothelial dysfunction and impairing vascular reactivity thus contributing to the pathogenesis of alterations in baroreceptor insensitivity, and cardiovascular diseases, including hypertension and atherosclerosis. Furthermore, fine particulate matter from dust may penetrate deep into the respiratory tract, activating pulmonary sensory receptors and eliciting reflex responses that influence autonomic tone. The presence of rich acrolein smokes and non-essential heavy metals such as cadmium, lead, and mercury in Harmattan wind also reduces baroreflex sensitivity, culminating in a sustained increase in diastolic and systolic blood pressure. This integrated review aims to provide valuable insights into how changes in each of these environmental constituents alter vital pathophysiologic and immunologic mechanisms of the body leading to baroreceptor instability and ultimately hemodynamic imbalance using available primary studies. Understanding this intricate interplay is crucial for implementing targeted interventions and informed public health strategies to mitigate the adverse effects of extreme environmental exposure and ultimately reduce poor health outcomes in the affected regions.

Assessing impact of elevated CO2 on heavy metal accumulation in crops: meta-analysis and implications for food security

Human activities led to elevation in carbon dioxide (CO2) concentrations in atmosphere. While such increase per se may be beneficial for the growth of some crops, it comes with a caveat of affecting crop nutritional status. Here, we present a comprehensive analysis of changes in concentration of essential (Cu, Fe, Mn, Zn, Mo, Ni) and non-essential (Ba, Cd, Cr, Hg, Pb, and Sr) heavy metals in response to elevated CO2, drawing on a meta-analysis of 1216 paired observations. The major findings are as follows: (1) Elevated CO2 leads to reduced concentrations of Cu, Fe, Mn, and Zn in crops; (2) the extent of above reduction varies among plants species and is most pronounced in cereals and then in legumes and vegetables; (3) reduction in accumulation of non-essential (toxic) metals is less pronounced, potentially leading to an unfavorable essential/non-essential metal ratio in plants; (4) the above effects will come with significant implication to human health, exacerbating effects of the “hidden hunger” caused by the lack of Fe and Zn in the human diets. The paper also analyses the mechanistic basis of nutrient acquisition (both at physiological and molecular levels) and calls for the changes in the governmental policies to increase efforts of plant breeders to create genotypes with improved nutrient use efficiency for essential micronutrients while uncoupling their transport from non-essential (toxic) heavy metals.

Low concentrations of methyl jasmonate promote plant growth and mitigate Cd toxicity in Cosmos bipinnatus

Cadmium (Cd) is a biologically non-essential heavy metal, a major soil pollutant, and extremely harmful to plants. The phytohormone methyl jasmonate (MeJA) plays an important role in plant heavy-metal resistance. However, the understanding of the effects of MeJA supply level on alleviating Cd toxicity in plants is limited. Here, we investigated how MeJA regulated the development of physiological processes and cell wall modification in Cosmos bipinnatus. We found that low concentrations of MeJA increased the dry weight of seedlings under 120 µM Cd stress by reducing the transport of Cd from roots to shoots. Moreover, a threshold concentration of exogenous MeJA increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in plant roots, the concentration of Cd in the root cell wall, and the contents of pectin and hemicellulose 1 polysaccharides, through converting Cd into pectin-bound forms. These results suggested that MeJA mitigated Cd toxicity by modulating root cell wall polysaccharide and functional group composition, especially through pectin polysaccharides binding to Cd, with effects on Cd transport capacity, specific chemical forms of Cd, and homeostatic antioxidant systems in C. bipinnatus.

Adaptation and Heavy Metal Degradation by Bacillus sp.: Insights Into Biofilm Formation, Exopolysaccharide (EPS) Production, and Antibiotic Resistance Under Copper (Cu) and Lead (Pb) Stress

ABSTRACTAn extensive concentration of heavy metals in our environment creates a harmful impact on living organisms, including microorganisms. Regardless of exploring the remediation potential of bacteria, their corresponding changes have not been extensively examined, which might be crucial before promoting bioremediation technology. The present study aimed to determine the effects of both essential (Cu) and nonessential (Pb) heavy metals on the bioactivity of a ubiquitous bacterium Bacillus sp., to gain knowledge about the adaptive mechanisms the strain has developed to withstand exposure to these metals. Bacterial adaptation is related to the formation of biofilm and the production of exopolysaccharides (EPSs) along with other tactics that assist in the survival of bacteria. When Bacillus sp. was cultured with Cu and Pb, changes in its bioactive characteristics were observed, such as a significant reduction in biofilm formation by 30.13% compared to the initial value. Moreover, the output of EPS by the bacterial strain in the presence of Pb increased to 0.782 mg/mL compared to the control condition, where no EPS was formed. In the presence of Cu, a low concentration of EPS (0.103 mg/mL) was detected. Moreover, the bacterial strain demonstrated adapted resistance to 6 out of 11 tested antibiotics, where the strain transformed from intermediate sensitivity to being susceptible to doxycycline, chloramphenicol, and gentamycin. Finally, the Cu‐ and Pb‐degrading capacity of the bacterium was scrutinized using a flame atomic absorption spectrophotometer, where the bacterium exhibited significant degradation rates, breaking down 14.49% of Cu and 37.30% of Pb within 7 days. This research revealed the adaptability of the bacterial strain to survive in the presence of Cu and Pb while degrading them, by changing its bioactive properties, through the downregulation of biofilm formation, the productivity of EPS, and the heavy metal degradation process.

Plastic ingestion, accumulated heavy metals, and health metrics of four Larus gull species feeding at a coastal landfill in eastern Canada

The objectives of this research were to assess ingested plastics and accumulated heavy metals in four urban gull species. Additionally, the relationships between ingested plastics and selected demographic and health metrics were assessed. Between 2020–2021 during the non-breeding seasons, 105 gulls (46 American herring gulls (HERG, Larus argentatus smithsonianus), 39 great black-backed gulls (GBBG, Larus marinus), 16 Iceland gulls (Larus glaucoides), 4 glaucous gulls (Larus hyperboreus)) were killed at a landfill in coastal Newfoundland and Labrador, Canada, as part of separate, permitted kill-to-scare operations related to aircraft safety. Birds were necropsied, the upper gastrointestinal tract contents were processed using standard techniques, and livers were analyzed for accumulated As, Cd, Hg, and Pb. The relationships between ingested plastics, demographics, and health metrics were assessed in HERG and GBBG. Across all four species, 85 % of birds had ingested at least one piece of anthropogenic debris, with 79 % ingesting at least one piece of plastic. We detected interspecific differences in plastic ingestion and hepatic trace metals, with increased ingested plastics detected in GBBG compared with HERG. For GBBG, levels of ingested plastic were relatively greater for birds with higher scaled mass index, while HERG with more ingested plastic had higher liver lead concentrations.

Effects of Exogennous Ebr on Physiological And Biochemical Characteristics of Soybean Under Cadmium Stress

Cadmium (Cd) is one of the highly toxic, non-essential heavy metals that inhibit plant growth and development. The differences in physiological indicators and leaf microstructure between cadmium-tolerant and cadmium-sensitive soybean under Cd stress were studied. The results showed that the photosynthetic efficiency of cadmium-sensitive soybeans was higher after cadmium stress so as to maintain the normal growth of the plants. Compared with that of cadmium-tolerant soybeans, the photosynthetic rate of cadmium-sensitive soybeans under cadmium stress had a higher correlation with each physiological indicator. Overall, EBR affected cadmium-tolerant soybean under cadmium stress mainly by changing the leaf cell structure and maintaining the integrity of cell structure, thereby increasing the net photosynthetic rate of soybean leaves, ultimately maintaining the normal growth of plants. Bangladesh J. Bot. 53(2): 327-335, 2024 (June)

Interaction between depression and non-essential heavy metals (Cd, Pb, and Hg) on metabolic diseases

ObjectivesMetal exposure and depression have each been associated with adverse metabolic diseases, but no study has examined the potential interaction between them. We examined the interaction of depression on the association between metals and metabolic diseases among adults. Study designThe interaction of depression in the relationship between metal and metabolic disease in adults was investigated using NHANES, a cross-sectional survey design. MethodsBy employing data from the NHANES database spanning the years 2007–2018, regression models were employed to investigate the independent impacts of heavy metals (cadmium, lead, and mercury) and depression on metabolic diseases (type 2 diabetes, hypertension, hyperlipidemia, metabolic syndrome). Subsequently, the association between metals and metabolic diseases was explored stratified by depression, and the interaction between heavy metals and depression was explored. Because of the complex NHANES design, statistical evaluations were adjusted through weighting to represent the populace of the United States. ResultsWe found log transformed-urinary lead was significantly associated with type 2 diabetes (OR: 2.33; 95 % CI: 1.23, 4.41) in adults with depression. Log transformed-urinary lead was not associated with type 2 diabetes (OR: 0.84; 95 % CI: 0.56, 1.27) in adults without depression. The interaction between Pb and depression in type 2 diabetes was significant (P for interaction = 0.033). Log transformed-urinary lead * depression was significantly associated with type 2 diabetes (OR: 1.82; 95 % CI: 1.01, 3.34) in adults. There was no significant interaction between cadmium and mercury exposure and depression in patients with type 2 diabetes, hypertension, hyperlipidemia, and metabolic syndrome (P for interaction > 0.05). ConclusionsThe presence of depression positively modified the adverse associations between urinary lead and type 2 diabetes.

Effect of Coffea canephora Bean Extract on Lead Acetate-Induced Rats

Lead (Pb) is a non-essential heavy metal that is toxic and has no known uses. Most cases of poisoning in livestock are caused by lead poisoning. This study aims to determine the effect of Coffea canephora bean extract as an antioxidant on the heart histopathological features of white rats (Rattus norvegicus) induced by lead acetate. This study used 25 male Wistar rats aged between eight and ten weeks and weighing between 200 and 250 grams. The rats were divided into five treatment groups, namely negative control (C-), positive control (C+), treatment one (T1), treatment two (T2), and treatment three (T3). The results suggested that the administration of 200 mg/kg BW, 400 mg/kg BW, or 800 mg/kg BW of Coffea canephora bean extract was not effective in improving the heart histopathological features, including cell degeneration, hemorrhage, and necrosis, of rats induced with lead acetate at a dose of 2 mg/kg BW.

Lead-induced liver fibrosis and inflammation in mice by the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways: the role of Isochlorogenic acid a.

Lead (Pb) is a nonessential heavy metal, which can cause many health problems. Isochlorogenic acid A (ICAA), a phenolic acid present in tea, fruits, vegetables, coffee, plant-based food products, and various medicinal plants, exerts multiple effects, including anti-oxidant, antiviral, anti-inflammatory and antifibrotic functions. Thus, the purpose of our study was to determine if ICAA could prevent Pb-induced hepatotoxicity in ICR mice. An evaluation was performed on oxidative stress, inflammation and fibrosis, and related signaling. The results indicate that ICAA attenuates Pb-induced abnormal liver function. ICAA reduced liver fibrosis, inflammation and oxidative stress caused by Pb. ICAA abated Pb-induced fibrosis and decreased inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). ICAA abrogated reductions in activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Masson staining revealed that ICAA reduced collagen fiber deposition in Pb-induced fibrotic livers. Western blot and immunohistochemistry analyses showed ICAA increased phosphorylated AMP-activated protein kinase (p-AMPK) expression. ICAA also reduced the expression of collagen I, α-smooth muscle actin (α-SMA), phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated c-jun N-terminal kinase (p-JNK), p-p38, phosphorylated signal transducer and phosphorylated activator of transcription 3 (p-STAT3), transforming growth factor β1 (TGF-β1), and p-Smad2/3 in livers of mice. Overall, ICAA ameliorates Pb-induced hepatitis and fibrosis by inhibiting the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways.

Analysis of Cadmium (Cd) Heavy Metal Levels in Groundwater around Lapindo Mudflow, Sidoarjo Regency

Background & Objective: Metal pollution in Lapindo mudflow is one of the events that cause pollution because the content in the mud contains a variety of heavy metals, one of which is cadmium (Cd). Cadmium is a heavy metal that has high toxicity and is included in non-essential heavy metals, so the presence of heavy metal cadmium (Cd) needs to be known for sure because too high levels can harm health and the surrounding environment. The purpose of this study is to determine the presence of cadmium (Cd) heavy metal levels in groundwater around Lapindo Mudflow, Sidoarjo Regency. Method: This study uses descriptive type and design. The sampling technique used purposive sampling by taking 4 points and conducting a duplo examination so that the total number of samples was 8 samples. Results: The results showed that out of 8 samples, all samples still met the requirements according to SNI with a percentage of 100%. Conclusion: It can be concluded that the results of the study with an average of 0.5075 × 10-4 mg/L still meet the requirements in accordance with the Indonesian National Standard (SNI) which is 0.5 - 10.0 mg/L or 0.0005 - 0.001 mg/L.

The Impact of Thallium Exposure in Public Health and Molecular Toxicology: A Comprehensive Review.

This review offers a synthesis of the current understanding of the impact of low-dose thallium (Tl) on public health, specifically emphasizing its diverse effects on various populations and organs. The article integrates insights into the cytotoxic effects, genotoxic potential, and molecular mechanisms of thallium in mammalian cells. Thallium, a non-essential heavy metal present in up to 89 different minerals, has garnered attention due to its adverse effects on human health. As technology and metallurgical industries advance, various forms of thallium, including dust, vapor, and wastewater, can contaminate the environment, extending to the surrounding air, water sources, and soil. Moreover, the metal has been identified in beverages, tobacco, and vegetables, highlighting its pervasive presence in a wide array of food sources. Epidemiological findings underscore associations between thallium exposure and critical health aspects such as kidney function, pregnancy outcomes, smoking-related implications, and potential links to autism spectrum disorder. Thallium primarily exerts cellular toxicity on various tissues through mitochondria-mediated oxidative stress and endoplasmic reticulum stress. This synthesis aims to shed light on the intricate web of thallium exposure and its potential implications for public health, emphasizing the need for vigilant consideration of its risks.

Pharmacological Effect of In Vitro Antioxidant Property and Green Synthesis of Silver Nanoparticles (AgNPs) Utilizing Murraya koenigii Antibacterial Application

ABSTRACT Background: Nonessential heavy metals pose a significant threat to human health due to their toxicity. Mercury, in particular, is identified as a hazardous metal. The study aims to detect mercury using colorimetric analysis with Murraya koenigii, emphasizing the eco-friendliness of the method. Aims and Objectives: The primary objective is to detect mercury using a colorimetric analysis method employing Murraya koenigii. Additionally, the study aims to investigate the eco-friendliness of this detection method. Materials and Methods: Colorimetric analysis was conducted using Murraya koenigii to detect mercury. Ultraviolet-visible (UV-vis) spectroscopy was employed to detect the formation of silver nanoparticles (AgNPs), with a characteristic surface plasmon resonance (SPR) band observed. X-ray diffraction (XRD) data analysis was performed to determine the crystalline nature and size of AgNPs. Scanning electron microscopy (SEM) was utilized to visualize the morphology of AgNPs. Fourier transform infrared (FTIR) spectroscopy was employed to identify functional groups involved in reducing silver ions. Antibacterial properties of synthesized AgNPs were tested against various microorganisms, including Escherichia coli, Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. Results: Mercury was successfully detected using colorimetric analysis with Murraya koenigii. Formation of AgNPs was confirmed by UV-vis spectroscopy, with a characteristic SPR band at 418 nm. AgNPs were found to be crystalline with an average size of 5.20 nm, as determined by XRD analysis. SEM images revealed spherical and polycrystalline AgNPs. FTIR spectra indicated the involvement of the -OH group of compounds in the extract in reducing silver ions. Synthesized AgNPs exhibited antibacterial properties against various microorganisms. Conclusion: A sustainable and eco-friendly method for synthesizing AgNPs using Murraya koenigii extract was successfully developed. This method not only detected mercury but also demonstrated antibacterial properties against various microorganisms. The study underscores the health implications of nonessential heavy metals, emphasizing the importance of eco-friendly detection and mitigation methods.

Phytochemical Analysis of Silver Nanoparticles of Psidium guajava Leaf Extract and Evaluation for Its Antibacterial Property.

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Murraya koenigii. The eco-friendliness of this method was also emphasized. UV spectrum is a broad peak observed at 200-250 nm in P. guajava leaf extracts. The UV spectrum of green synthesized P. guajava exhibited an absorption band of 418 nm, which confirms the nanoparticle synthesis. FTIR analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic β-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the SEM image that the constituent parts were non-uniform sphere-shaped, agglomerated, and of an average size of 30.9 nm. XRD analysis was utilized to determine the structural characteristics and crystalline nature of P. guajava. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° represent the 2θ values for P. guajava in the diffraction pattern, aligning with the values in the standard database. The synthesized AgNPs tested antibacterial properties against various strains of microorganisms, including Escherichia coli, 25 μg/mL 6.02 ± 0.17 and 100 μg/mL 7.3 ± 0.05, Staphylococcus aureus, 25 μg/mL 05.02 ± 0.07 and 100 μg/mL 11.3 ± 1.12, Streptococcus mutans, 25 μg/mL 04.02 ± 0.19 and 100 μg/mL 11.1 ± 0.11, Enterococcus faecalis, 25 µg/mL 0.8.05 ± 0.11 and 100 µg/mL 11.7 ± 0.02. The short novelty of Psidium guajava (guava) lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.

Phytochemical Analysis of Silver Nanoparticles of Zingiber officinale and Evaluation for Its Antibacterial Property.

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Zingiber (Z.) officinale. The eco-friendliness of this method was also emphasized. The ultraviolet (UV) spectrum is a broad peak observed at 200-250 nm in Z. officinale leaf extracts. The UV spectrum of green synthesized Z. officinale exhibited an absorption band of 286 nm, which confirms the nanoparticle (NP) synthesis. Fourier transform infrared (FTIR) analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic β-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the scanning electron microscope (SEM) image that the constituent parts were nonuniform, sphere-shaped, agglomerated, and of an average size of 30.9 nm. X-ray diffraction (XRD) analysis was used to determine the structural characteristics and crystalline nature of Z. officinale. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° are, respectively, of the Z. officinale diffraction 2θ values, which correspond to the standard database values. The synthesized copper NPs synthesized tested antibacterial properties against various strains of microorganisms, including Escherichia coli: 25 μg/mL 2.01 ± 0.11 and 100 μg/mL 5.37 ± 0.12, Staphylococcus (S.) aureus: 25 μg/mL 1.05 ± 0.71 and 100 μg/mL 11.43 ± 1.27, Streptococcus mutans: 25 μg/mL 02.01 ± 0.1 and 100 μg/mL 15.67 ± 0.17, and Enterococcus faecalis: 25 μg/mL 03.11 ± 0.7 and 100 μg/mL 18.32 ± 0.2. The short novelty of Z. officinale lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.

Elemental composition and mineralogical characteristics of volcanic ash and soil affected by the eruption of Mount Semeru, East Java

Elemental composition and mineralogical characteristics of volcanic ash and soil affected by the eruption of Mount Semeru, East Java

Heavy metal tolerance and accumulation in the Brassica species (Brassica chinensis var. parachinensis and Brassica rapa L.): A pot experiment

This study delves into the heavy metal tolerance and accumulation capabilities of Brassica chinensis var. parachinensis (B. chinensis) and Brassica rapa L. (B. rapa) in a pot experiment, specifically focusing on cadmium (Cd), chromium (Cr) and lead (Pb). Agricultural topsoils were spiked with varying concentrations of these heavy metals (0 mg/kg, 75 mg/kg, 150 mg/kg, 225 mg/kg and 300 mg/kg) for each element. The experiment involved cultivating 15 pots each of B. chinensis and B. rapa over 60 days. Results indicated that both Brassica species experienced delayed germination, with B. chinensis exhibiting a significant drop in germination percentage to 53 % at the highest concentration (300 mg/kg), while B. rapa showed a tendency for an increased germination percentage of up to 80 % at elevated metal concentrations; however, these differences were not statistically significant. Both B. chinensis and B. rapa demonstrated a stable decline in growth rate from 0.05 cm/day to 0.04 cm/day with increasing heavy metal concentrations, and the he reduction in relative growth rate was significant at the highest concentration compared to the control. The stress tolerance index revealed a significant decrease in plant heights for B. chinensis, in contrast to the stable performance of B. rapa, showcasing the tolerance of B. rapa to toxic conditions. Despite insignificant differences in fresh biomass due to metal treatments, B. chinensis consistently yielded higher biomass, yet it had a lower edible index due to its higher root biomass. Leaf areas increased significantly in both species at higher soil treatments, while root lengths remained unchanged, suggesting their resilience to elevated heavy metal concentrations. Analysis of plant tissues (leaves, stems and roots) using ICP-OES revealed that B. rapa accumulated the highest Cd concentration (864 mg/kg), whereas B. chinensis accumulated the highest Pb concentration (953 mg/kg) in root parts. Both species significantly accumulated Cr in roots, demonstrating a sequestration mechanism. These findings suggest that both species, particularly, B. rapa possess strong tolerance and accumulation capabilities for non-essential heavy metals, making them potential hyperaccumulators for green remediation techniques in toxic soil environments. Understanding the molecular mechanisms driving these responses and validating phytoremediation potential in real-world scenarios is essential for developing sustainable soil management practices.

Fertility and heavy metal pollution in silage maize soil irrigated with different levels of recycled wastewater under conventional and no-tillage practices

AbstractIrrigation with recycled domestic wastewater has been known to obtain positive effects on improving soil fertility, but it may also become a risk factor in case of causing an increase in soil salinity and/or heavy metal concentration of soil. No-tillage can retain soil moisture, helping to reduce irrigation water necessity, and thus lower amounts of heavy metals and salts are added to soil under wastewater irrigation conditions. The objective of this study was to analyze the effects of wastewater irrigation at different levels of on silage maize cultivation under conventional tillage and no-tillage conditions by comparing to full irrigation with fresh water. The two-year experiment was planned according to the split-plots design in the random blocks with three replications. The results indicated that full irrigation with wastewater increased soil salinity, organic matter content, total nitrogen, plant available phosphous, exchangeable cations, exchangeable sodium percentage and soil essential and non-essential heavy metal contents, but decreased soil pH and lime content. Increasing rates in organic matter content, total nitrogen, plant available phosphorus and exchangeable potassium were higher, but in electrical conductivity, and heavy metal accumulation were lower in soil under no-tillage as compared to conventional tillage. Contamination and enrichment factors and geographic accumulation index showed that non-essential heavy metal contamination due to cadmium and nickel, increased in full irrigation with wastewater. Irrigation with wastewater also increased heavy metal accumulation in silage maize. No-tillage can be a recommendable water management practice considering that the risks of soil salinity and heavy metal accumulation can be reduced and that soil fertility can be increased. Also, in reducing the risk of accumulation of cadmium and nickel in soil, 33% deficit irrigation with wastewater can make no-tillage more available.

LITERATURE REVIEW: METALLOTHIONEIN SEBAGAI PROTEIN PENGIKAT LOGAM UNTUK BIOREMEDIASI LOGAM BERAT

Background: The purpose of bioremediation is to remove or reduce dangerous compounds to improve environmental quality, one of which is heavy metals. Metal-binding proteins can minimize the impact of heavy metal pollution from the environment. This metal binding protein can accumulate metals by microorganisms. One of the known metal-binding proteins is metallothioneins (MTs). This protein can minimize the effects of heavy metals in the environment by creating protein-metal ion complex bonds. This review article provides a comprehensive insight into the role of metallothionein as a metal-binding protein for heavy metal accumulation, and the mechanisms involved in heavy metal bioremediation Methods: The method used is a literature review using reputable national and international journals. Results: Based on the results of a literature review, metallothionein can be found in many organisms such as bacteria, humans, plants, invertebrates, and mammals. Metallothionein can accumulate heavy metals that contain highly conserved cysteine residues. These residues allow MTs to bind, transport, and store various essential (Zn and Cu) and non-essential (Cd and Hg) heavy metals via thiolate bonding. Conclusion: Heavy metals are dangerous for the survival of living things and can cause damage to vital functions. One of the metal-binding proteins is metallothionein, which is involved in the organism's tolerance to heavy metal content and can accumulate it, so that the effects of heavy metals can be minimized.

Gene expression variation underlying tissue-specific responses to copper stress in Drosophila melanogaster.

Copper is one of a handful of biologically necessary heavy metals that is also a common environmental pollutant. Under normal conditions, copper ions are required for many key physiological processes. However, in excess, copper results in cell and tissue damage ranging in severity from temporary injury to permanent neurological damage. Because of its biological relevance, and because many conserved copper-responsive genes respond to nonessential heavy metal pollutants, copper resistance in Drosophila melanogaster is a useful model system with which to investigate the genetic control of the heavy metal stress response. Because heavy metal toxicity has the potential to differently impact specific tissues, we genetically characterized the control of the gene expression response to copper stress in a tissue-specific manner in this study. We assessed the copper stress response in head and gut tissue of 96 inbred strains from the Drosophila Synthetic Population Resource using a combination of differential expression analysis and expression quantitative trait locus mapping. Differential expression analysis revealed clear patterns of tissue-specific expression. Tissue and treatment specific responses to copper stress were also detected using expression quantitative trait locus mapping. Expression quantitative trait locus associated with MtnA, Mdr49, Mdr50, and Sod3 exhibited both genotype-by-tissue and genotype-by-treatment effects on gene expression under copper stress, illuminating tissue- and treatment-specific patterns of gene expression control. Together, our data build a nuanced description of the roles and interactions between allelic and expression variation in copper-responsive genes, provide valuable insight into the genomic architecture of susceptibility to metal toxicity, and highlight candidate genes for future functional characterization.

Micro-essential and toxic heavy metals in surface water of Harike wetland - India

Wetlands are consequential habitats with diverse flora and fauna. The overutilization of these habitats led to the implementation of conservational strategies which includes Ramsar convention. Harike wetland is the largest wetland in northern India, declared as a Ramsar site. However, the recent industrialization and anthropogenic activities may result in the ecological degradation of this wetland. The wetland is eminently polluted due to industrial discharges, therefore the present study was undertaken to investigate heavy metal status of Harike wetland. The analysis included bio-essential (chromium, manganese, iron, cobalt, nickel, copper, zinc) and non-essential (arsenic, mercury, cadmium, lead) heavy metals. The concentration of heavy metals in the surface water was determined using inductively Coupled Plasma-Mass Spectrometry and the recovered values were compared to the global and national standards. Among all the heavy metals analysed the mean concentrations of iron (437.983 µg/l), mercury (4.011 µg/l) and lead (156.719 µg/l) were recorded to be alarming. The higher concentration of heavy metals may be directly related to the inlet from river Sutlej, as the water is contaminated by various industrial, domestic and agricultural sources. Therefore, continuous monitoring and adequate measures need to be implemented to improve the water quality of internationally recognized wetland.