Metal Exposure Research Articles

Machine learning model for age-related macular degeneration based on heavy metals: The National Health and Nutrition Examination Survey 2005 to 2008.

Age-related macular degeneration (AMD) is the leading cause of blindness in older people in developed countries. It has been suggested that heavy metal exposure may be associated with the development of AMD, but most studies have focused on the effects of a single metal with traditional methods. In this study, we analyzed the relationship between 13 urinary heavy metal concentrations and AMD using NHANES data between 2005 and 2008. We constructed and compared 11 machine learning models to identify the best model for predicting AMD risk. We further interpreted the models by Permutation Feature Importance (PFI), Partial Dependence Plot (PDP) analysis, and SHapley Additive exPlanations (SHAP) analysis. 216 AMD patients out of 2380 participants. The random forest (RF) model performed optimally in predicting the risk of AMD, with an AUC value of 0.970. PFI analyses revealed that age and urinary cadmium (Cd) were the main factors influencing the risk of AMD. SHAP analyses further confirmed the significance of Cd concentration in predicting the risk of AMD, and we revealed a significant interaction with significant interaction of race. Our study firstly explored the relationship between heavy metal exposure levels and AMD based on machine learning techniques, found that urinary Cd concentration had the greatest impact on AMD, and revealed the superior predictive performance of machine learning methods. Furthermore, our study provided a new perspective for early screening and intervention of AMD.

Interactive association of metals and Life's Essential 8 with mortality in U.S. adults: a prospective cohort study from the NHANES dataset.

Life's Essential 8 (LE8) is a novel assessment of cardiovascular health (CVH) by evaluating lifestyle, and reports of the associations between LE8 and urinary metals on mortality have been very limited. This study aimed to conduct a prospective cohort study and investigate the combined effects of metals and LE8 on mortality in U.S. adults. This study enrolled participants with complete information on urinary metals, LE8, mortality status, and confounders from the National Health and Nutrition Examination Survey (2005-2018). The Cox regression model, adaptive lasso penalized regression, and restricted cubic spline were used to analyze the individual effects of metals and LE8 on all-cause mortality. The additive and multiplicative interaction scales and quantile g-computation were used to evaluate the interaction and combined effects. Stratified analyses were performed to clarify whether metals and LE8 interacted with other variables to influence all-cause mortality. A total of 8017 participants were included in this study. The concentrations of cadmium, cobalt, lead, antimony, and thorium were greater in the low CVH group than in the high CVH group [median (µg/L): 0.29 vs. 0.19, 0.36 vs. 0.35, 0.48 vs. 0.39, 0.05 vs. 0.04, and 0.07 vs. 0.06]. The interaction between cadmium and LE8 was statistically significant, with a synergy index of 1.169 (95% CI: 1.004, 1.361). The stratified analyses showed that the interaction between age and LE8 had an impact on all-cause mortality (P for interaction = 0.004). In this representative sample of the U.S. population, we found that the combined effect of cadmium, lead, thallium, and LE8 was positively associated with all-cause mortality. Furthermore, the interaction between cadmium and LE8 influenced all-cause mortality. So people should adopt healthy behaviors and reduce heavy metal exposure to minimize the risk of adverse health outcomes.

Cross-sectional study on urinary metal concentrations in young adult residents of Emirate of Sharjah, United Arab Emirates.

Human biomonitoring is crucial for regulatory toxicology, yet data on biomarker concentrations in the UAE are lacking. This study addresses this gap by analyzing urinary concentrations of 16 metals in UAE young adults, assessing correlations with personal characteristics, dietary patterns, and lifestyle habits. A cross-sectional pilot study was conducted among 144 randomly selected young adults (71 males and 73 females) from Sharjah, UAE, between January and March 2023. Participants provided urine samples, which were analyzed for 16 heavy metals using ICP-OES, and completed detailed questionnaires covering sociodemographic factors, lifestyle, and dietary habits. Descriptive statistics were used to summarize participant characteristics, and linear regression analysis was applied to explore associations between metal concentrations and factors such as gender, dietary habits, and exposure to environmental risks. Non-parametric tests, including the Mann-Whitney test, were used to assess differences by gender. Statistical significance was set at p < 0.05. Ethical approval was obtained, and informed consent was secured before participation. Significant findings include dietary influences on metal exposure, with rice consumption linked to higher metal concentrations. Sex differences were significant, with females showing elevated levels of arsenic, lead, and cadmium. Lifestyle factors, such as smoking and incense use, were correlated with increased barium and boron levels. This study highlights the significant role of dietary habits, especially the consumption of rice, in metal exposure among young adults in Sharjah. The findings highlight the urgent need for comprehensive human biomonitoring to understand environmental exposures and reform public health policies. The gender-specific differences in metal distribution suggest the necessity for targeted public health strategies. The study, however, is limited by its cross-sectional nature and the focus on a specific geographic area, warranting further research for broader generalizability. Future investigations, particularly on the impact of incense exposure on metal levels, are essential for developing comprehensive health interventions and preventive strategies in the UAE.

Immune defense adaptation of Strauchbufo raddei population in heavy metal polluted area: Insights from developmental and environmental perspectives

The adjustment of immune defense mechanisms is a crucial aspect of biological adaptation to stressful environments. Amphibians, with their unique metamorphic process, experience distinct life stages and exhibit diverse immune defense components. While previous studies have focused on specific immune changes during particular life stages under stress, this research addresses a critical gap by exploring the adaptive immune defense strategies of Strauchbufo raddei in heavy metal-polluted environments. We conducted laboratory experiments, exposing offspring from both polluted and unpolluted areas to control and heavy metal treatments, while continuously monitoring changes in immune components during key metamorphic stages. Notably, we examined the role of the skin microbiome, a crucial but often overlooked barrier against pathogens. The results indicated that individuals from polluted areas exhibited some tolerance to heavy metal exposure, though overall immune function remained diminished. During metamorphosis, when immune defenses are most vulnerable, the skin microbiome rapidly enriched beneficial bacteria, preventing pathogenic colonization and playing a pivotal role in maintaining immune defense in contaminated environments. Moreover, our research highlights energy allocation strategies involving corticosterone and body fat content, enabling populations to maintain development despite immune compromise. The immune adaptations observed may be fixed through genetic assimilation, suggesting a rapid evolutionary response to environmental stress. However, this reduces phenotypic plasticity, making populations more vulnerable to future environmental changes. This study provides key insights into the survival strategies of amphibian populations in heavy metal-contaminated areas, laying the foundation for future research on molecular and evolutionary adaptations.

Environmental Heavy Metal Exposure and Associated Cardiovascular Diseases in Light of the Triglyceride Glucose Index.

Cardiovascular diseases (CVD), primarily ischemic heart disease and stroke, remain leading global health burdens. Environmental risk factors have a major role in the development of CVD, particularly exposure to heavy metals. The Triglyceride Glucose Index (TyG), a measure of insulin resistance and CVD risk, is the primary focus of this study, which summarizes the most recent findings on the effects of lead (Pb), arsenic (As), and cadmium (Cd) on CVD risk. A higher risk of CVD is correlated with an elevated TyG index, which has been linked to insulin resistance. Exposure to Cd is associated with disturbance of lipid metabolism and oxidative stress, which increases the risk of CVD and TyG. Exposure reduces insulin secretion and signaling, which raises the TyG index and causes dyslipidemia. Pb exposure increases the risk of CVD and TyG index via causing oxidative stress and pancreatic β-cell destruction. These results highlight the need of reducing heavy metal exposure by lifestyle and environmental modifications in order to lower the risk of CVD. To comprehend the mechanisms and create practical management plans for health hazards associated with heavy metals, more study is required.

Akkermansia muciniphila attenuates the association between specific metal exposures during pregnancy and depressive symptoms in late childhood

Akkermansia muciniphila attenuates the association between specific metal exposures during pregnancy and depressive symptoms in late childhood

Modulatory effects of inorganic mercury (Hg (II)) and lead (Pb (II)) on immune responses of Pekin ducklings (Anas platyrhynchos domesticus) upon a viral-like immune challenge

Trace metal contamination is ubiquitous around the world and may affect the health of wildlife. Divalent trace metals, including ions of mercury (Hg) and lead (Pb), have been shown to be immunotoxic to avian species. However, little is known about the immunomodulatory effects of trace metal exposure on viral infections, especially in young birds, who may be more sensitive. Therefore, the objective of the current study is to provide more insights in the causality between trace metal exposure and the effects of exposure on the immune responses in young waterfowls. Pekin duckling was used as an animal model to investigate the effects of inorganic divalent Hg (II) and Pb (II) on avian immune responses upon a viral-like challenge with double-stranded RNA. Our results indicate that Hg (II) altered the immune gene expression 24 h post-challenge, as reflected by induction of pro-inflammatory genes IL-8, iNOS, TLR3 and TLR7, and a significant decrease of microRNA-155. Ducklings exposed to Pb (II) showed lower levels of natural antibodies, reduced white blood cell counts and lower heterophil proportions 24 h post-challenge. Although inorganic divalent Hg (II) and Pb (II) showed specific differential effects on the immune response of Pekin ducklings, the overall adverse immunomodulatory outcomes in both cases point to inflammation, impaired B-cell function, and weaker immunocompetence.

Associations of mixed metals exposure with cognitive impairment risk: a cross-sectional study in Chinese adults.

Associations between exposure to single metals and cognitive impairment or related outcomes have been reported in many previous studies. However, co-exposure to more than one metal is common situation. In recent years, studies on the effects of exposure to multiple metals on cognitive impairment or related outcomes have increased, but remain very limited, with a focus on populations with occupational exposure to metals, children, and adolescents. The potential relationships between exposure to metal mixtures and risk of cognitive impairment in adults remain to be clarified. To determine the associations between blood metal mixtures and cognitive impairment risk. Inductively coupled plasma mass spectrometry (ICP-MS) was utilized to detect the blood levels of lead (Pb), iron (Fe), copper (Cu), calcium (Ca), magnesium (Mg), and zinc (Zn). Multivariable logistic regression and Bayesian kernel machine regression (BKMR) models were employed to assess the relationships of exposure to these blood metal mixtures with the risk of cognitive impairment. It was found that four metals (Pb, Fe, Cu, and Mg) were positively correlated with cognitive impairment in each single metal model. The association of Pb and Cu remained significant after adjusting for these six metals, with the odds ratios (95% confidence intervals) in the highest quartiles of 9.51 (4.41-20.54, p-trend <0.01) and 4.87 (2.17-10.95, p-trend <0.01), respectively. The BKMR models indicated that co-exposure levels of Ca, Cu, Fe, Mg, Pb, and Zn were related to increased risk of cognitive impairment at ≥25th percentile compared with median, and Pb and Cu mainly contributed to the joint effect. In addition, the interaction effects of Mg and Pb/Pb and Cu on the risk of cognitive impairment were observed. Co-exposure of six metals (Pb, Fe, Cu, Ca, Mg, and Zn) increased the risk of cognitive impairment in Chinese adults, with Pb and Cu likely to have greater impact. Potential interaction effects of Mg and Pb, Pb and Cu on the risk of cognitive impairment may exist.

Erratum: Comparative Analysis of Heavy Metal Exposure Concentrations and Volatile Organic Compound Metabolites among Residents in the Affected Area According to Residential Distance from a Coal-fired Power Plant

Erratum: Comparative Analysis of Heavy Metal Exposure Concentrations and Volatile Organic Compound Metabolites among Residents in the Affected Area According to Residential Distance from a Coal-fired Power Plant

Prenatal metal exposures and kidney function in adolescence in Project Viva.

The developing kidney is vulnerable to prenatal environmental factors such as metal exposure, potentially altering the risk of later-life kidney dysfunction. This study examines the relationship between prenatal metal exposures, individually and as mixtures, and adolescent kidney function in Project Viva, a prospective longitudinal birth cohort in Massachusetts, USA. We used data on metals measured in blood during pregnancy including 15 in the first trimester and four in the second trimester. We calculated estimated glomerular filtration rate (eGFR) in adolescents (mean: 17.7 years) using cystatin C- (eGFRcys) and creatinine-based (eGFRcreat) equations for children. We used linear regression for single metal analyses, and Bayesian kernel machine regression and quantile-based g-computation for mixture analyses, adjusting for relevant covariates. To account for multiple comparisons in the single metal analyses, we applied the Holm-Bonferroni procedure to control the false discovery rate. This study included 371 participants with first trimester metals and adolescent eGFR, and 256 with second trimester metals. Each doubling in first trimester cadmium concentration was associated with lower adolescent eGFRcys (β:-1.51; 95% CI:-2.83, -0.18). Each doubling in first trimester chromium (β:-1.45; 95% CI:-2.71, -0.19), nickel (β:-1.91; 95% CI:-3.65, -0.16), and vanadium (β:-1.69; 95% CI:-3.21, -0.17) was associated with lower adolescent eGFRcreat. After adjusting for multiple comparisons, p-values for associations between adolescent eGFR and chromium, nickel, vanadium and cadmium did not meet the criteria for significance. Metal mixture analyses did not identify statistically significant associations with adolescent eGFR. These findings have important implications for future studies investigating the potential mechanisms through which prenatal metal exposures affect long-term kidney health in children.

Enhancing Aseptic Inflammation Resolution with 1-(2-Ethoxyethyl)-4-(pent-1-yn-1-yl)piperidin-4-yl Propionate: A Novel β-Cyclodextrin Complex as a Therapeutic Agent

The synthesized compound, 1-(2-ethoxyethyl)-4-(pent-1-yn-1-yl)piperidin-4-yl propionate (EPPP), and its 1:1 complex with β-cyclodextrin (EPPPβCD) have been characterized for the first time through a comprehensive suite of analytical methods. This study explores the therapeutic potential of EPPPβCD in modulating immune responses and accelerating the resolution of septic inflammation induced by chromium and vanadium ions in outbred male rats. The research highlights the significant impact of EPPPβCD on the dynamics of regulatory T lymphocytes (Tregs), notably causing a reduction in the CD4+CD25+ fractions at the onset of inflammation. This effect is attributed to the inhibition of Treg proliferation, which is crucial in hastening the resolution of inflammation. These findings underscore the potential of EPPPβCD as a promising therapeutic agent in controlling and mitigating inflammation mediated by heavy metal exposure, thereby offering a new avenue for the development of anti-inflammatory treatments.

A field study of the molecular response of brown macroalgae to heavy metal exposure: An (epi)genetic approach

Our understanding of the relative contribution of genetic and epigenetic mechanisms to organismal response to stress is largely biased towards specific taxonomic groups (e.g. seed plants) and environmental stresses (e.g. drought and salinity). In previous work, we found intraspecific differences in heavy metal (HM) uptake capacity in the brown macroalgae Fucus vesiculosus. The molecular mechanisms underlying these differences, however, remained unknown. Here, we evaluated the concentrations of HMs, and characterized the genetic (single nucleotide polymorphisms) and epigenetic (cytosine DNA methylation) variability in reciprocal transplants of F. vesiculosus between two polluted and two unpolluted sites on the NW Spanish coast after 90 days. Genetic and epigenetic differentiation did not explain the phenotypic differentiation observed, possibly due to the combined effect of multiple environmental factors acting on the algae in their natural habitats. Nonetheless, we provide further evidence of intraspecific genetic differentiation in F. vesiculosus at short spatial scales, as well as first evidence of population-specific epigenetic changes in brown macroalgae in response to changes in environmental conditions (i.e. transplantation ex situ). We propose that both genetic and, to some extent, epigenetic mechanisms might impinge upon the adaptive potential of this species to environmental change, but this needs to be further addressed.

Exposure to copper metal enhances the tolerance of An. gambiae s.s. over multiple generations while reducing both fertility and fecundity in this primary malaria vector.

Background Anopheles s.l. displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a significant biological cost, which can adversely affect its ecological fitness. This study investigated the larval metal exposure on larval development and reproduction of An. gambiae s.s., a laboratory susceptible strain, kisumu. Methods Stage 2 larvae of Anopheles gambiae, Kisumu were exposed to C1 = 484 μg L-1, C2 = 300 μg L-1 and 0 μg L-1 (control) of copper chloride. Larval mortality, pupation time, pupation rate, gonotrophic cycle length, fecundity and fertility of larvae/adults were assessed over six generations. Results Results revealed that larval mortality rate was significantly higher in the C1 groups of each group (p = 0.000), but this mortality rate decreased over generations. Pupation time was extended to 13 and 14 days respectively for C2 and C1 groups (p = 0.000) compared to the control group. Similar results were observed for the gonotrophic cycle, which increased from 4 days at G0 to more than 6 days at generation 5 in adults of C1. The pupation rate in generation 4 (C1) and generation 5 of the same group (p = 0.000) as well as the emergence rate in generation 4 (C2, p = 0.000) and generation 5 (C1 and C2, p = 0.000) decreased significantly compared to the control group. The average number of eggs laid was lower in the test groups from generation 4 to generation 5 (C1 and C2, p = 0.00) and egg fertility was also negatively affected by exposure of the larval stage of An. gambiae s.s. to copper. Conclusion Although studies have already shown that copper induces resistance in An. gambiae s.l. to insecticides, this study has shown that this adaptation requires a non-negligible biological cost in the life of the insect.

Combined Restraint Stress and Metal Exposure Paradigms in Rats: Unravelling Behavioural and Neurochemical Perturbations.

Accumulation of heavy metals (Mn and Ni) and prolonged exposure to stress are associated with adverse health outcomes. Various studies have shown the impacts of stress and metal exposures on brain function. However, no study has examined the effects of co-exposure to stress, Mn, and Ni on the brain. This study addresses this gap by evaluating oxidative and glial responses, apoptotic activity, as well as cognitive processes in a rat model. Adult Wistar rats were exposed to vehicle (control), restraint stress, 25mg/kg of manganese (Mn) or nickel (Ni), or combined restraint stress plus Mn or Ni. Following treatment, rats were subjected to several behavioural paradigms to assess cognitive function. Enzyme activity, as well as ATPase levels, were evaluated. Thereafter, an immunohistochemical procedure was utilised to evaluate neurochemical markers of glial function, myelination, oxidative stress, and apoptosis in the hippocampus, prefrontal cortex (PFC), and striatum. Results showed that stress and metal exposure increased oxidative stress markers and reduced antioxidant levels. Further, combined stress and metal exposure reduced various forms of learning and memory ability in rats. In addition, there were alterations in Iba1 activity and Nrf2 levels, reduced Olig2 and myelin basic protein (MBP) levels, and increased caspase-3 expression. These neurotoxic outcomes were mostly exacerbated by co-exposure to stress and metals. Overall, our findings establish that stress and metal exposures impaired cognitive performance, induced oxidative stress and apoptosis, and led to demyelination effects which were worsened by combined stress and metal exposure.

Mild polarization electric field in ultra-thin BN-Fe-graphene sandwich structure for efficient nitrogen reduction

The electrocatalytic N2 reduction reaction (NRR) is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient conditions. The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst, correct electron transfer direction, and electron tunneling distance between bare electrode and active sites. By coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method, an ultrathin sandwich catalyst, i.e., Fe atoms (polarized electric field layer) sandwiched between ultrathin (within electron tunneling distance) BN (catalyst layer) and graphene film (conducting layer), is fabricated for electrocatalytic NRR. The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure. The sandwich electrocatalyst NRR system achieve NH3 yield of 8.9 μg h−1 cm−2 and Faradaic Efficiency of 21.7%. The N2 adsorption, activation, and polarization electric field changes of three sandwich catalysts (BN-Fe-G, BN-Fe-BN, and G-Fe-G) during the electrocatalytic NRR are investigated by experiments and density functional theory simulations. Driven by applied voltage, the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

Sensitivity improvement of a deuterium-deuterium neutron generator based in vivo neutron activation analysis (IVNAA) system.

Our lab has been developing a deuterium-deuterium (DD) neutron generator-based neutron activation analysis (NAA) system to quantify metals and elements in the human body in vivo. The system has been used to quantify metals such as manganese, aluminum, sodium in bones of a living human. The technology provides a useful way to assess metal exposure and to estimate elemental deposition, storage and biokinetics. It has great potential to be applied in the occupational and environmental health fields to study the association of metal exposure and various health outcomes, as well as in the nutrition field to study the intake of essential elements and human health. However, the relatively low sensitivity of the system has greatly limited its applications. Neutron moderation plays an important role in designing an IVNAA facility, as it affects thermal neutron flux in irradiation cave and radiation exposure to the human subject. This study aims to develop a novel thermal neutron enhancement method to improve the sensitivity of the in vivo neutron activation analysis (IVNAA) system for elemental measurement but still maintain radiation dose. Utilizing a compact DD neutron source, we propose a new and practical moderator design that combines high density polyethylene with heavy water to enhance thermal neutrons by reducing thermal neutron absorption. All material dimensions are calculated by PHITS, a general-purpose Monte Carlo simulation program. The improvement of the new design predicted by the Monte Carlo simulation for the quantification of one of the elements, manganese was verified by experimental irradiation of manganese-doped bone equivalent phantoms. For the same radiation dose, a 67.9% thermal neutron flux enhancement is reached. With only 4.2% increase of radiation dose, the simulated thermal neutron flux and activation can be further increased by 84.2%. A 100% thermal neutron enhancement ratio is also achievable with a 20% dose increase. The experimental results clearly show higher manganese activation gamma ray counts for each specific phantom, with a significantly reduced minimum detection limit. Additionally, the photon dose was suppressed. The thermal neutron enhancement method can increase the number of useful neutrons significantly but maintain the radiation dose. This greatly decreased the detection limit of the system for elemental quantification at an acceptable dose, which will broadly expand the application of the technology in research and clinical use. The method can also be applied to other neutron medical applications, including neutron imaging and radiotherapy.

Human health risk assessment of metal contamination in cereals and pulses in the mica mining areas of Jharkhand, India

This study was carried to investigate the contamination levels of heavy in food crops (rice, wheat, maize, and pulses) grown in the vicinity of the mica mine in Jharkhand, India. Except for Pb and Zn in select places, the metal concentrations in the food crops were below the maximum allowed levels for food in India. The principal component analysis identified three components that accounted for 71.3 % of the variability in the data. The components that were retrieved indicated that soil, irrigation water, and air dust deposition could be the sources of metals in the food crops. The estimated daily intake (EDI) and target hazard quotient (THQ) of food crop consumption were used to highlight the potential health concerns associated with metal exposure. In several samples, local individuals' daily intakes of Pb was greater than the WHO's recommended daily intakes of these heavy metals. Taking into account the geometric mean of metal concentrations in food crops samples from the, the hazard index (HI) for the consumers was 10.28 which is far above unity. Pb, Co, and As were the primary contributors to the potential non-carcinogenic risk. The HI ranged from 7.22 to 18.29 across different locations, indicating a significant health risk to the consumers of locally grown food crops in the vicinity of the mica mining areas.

Accumulation of heavy metals (Cr, Cu, As, Cd, Pb, Zn, Fe, Ni, Co) in the water, soil, and plants collected from Edayar Region, Ernakulam, Kerala, India

The accumulation of heavy metals in the environment is a significant concern due to their potential toxicity and persistence. This study investigates the levels of heavy metal contamination in the water, soil, and plants of the Edayar region in Ernakulam, Kerala, India. The region has experienced industrialization and urbanization, leading to concerns about heavy metal pollution. The study aims to assess the concentrations of chromium (Cr), copper (Cu), arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn), iron (Fe), nickel (Ni), and cobalt (Co) in water, soil, aquatic and terrestrial plants. Samples were collected from various locations within the Edayar region, and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was conducted to quantify heavy metal concentrations. The findings of this study will contribute to the assessment of heavy metal pollution in the Edayar region. Plants with a high diversity index were taken for analysis from both aquatic and terrestrial habitats. Scoparia dulcis L. seems to specialize in metal accumulation, possibly for protective purposes. Synedrella nodiflora Gaertn demonstrates adaptability to metal-rich environments through robust metal uptake and tolerance mechanisms. Alternanthera philoxeroides (Mart.) Griseb, on the other hand, appears to have developed mechanisms to manage heavy metal exposure. The results indicate significant levels of heavy metal contamination across all samples, with the highest concentrations detected in soil, followed by water and plants. Chromium and lead levels in soil exceeded the permissible limits set by international standards, posing potential risks to human health and the ecosystem. The accumulation patterns in plants varied, with higher bioaccumulation factors observed for zinc and copper, suggesting their preferential uptake. This study highlights the urgent need for remediation strategies and continuous monitoring to mitigate the impact of heavy metal pollution in the Edayar region. The results will help in understanding the environmental impact of human activities.

The Effect of Larval Exposure to Heavy Metals on the Gut Microbiota Composition of Adult Anopheles arabiensis (Diptera: Culicidae).

Anopheles arabiensis is a highly adaptable member of the An. gambiae complex. Its flexible resting behaviour and diverse feeding habits make conventional vector control methods less effective in controlling this species. Another emerging challenge is its adaptation to breeding in polluted water, which impacts various life history traits relevant to epidemiology. The gut microbiota of mosquitoes play a crucial role in their life history, and the larval environment significantly influences the composition of this bacterial community. Consequently, adaptation to polluted breeding sites may alter the gut microbiota of adult mosquitoes. This study aimed to examine how larval exposure to metal pollution affects the gut microbial dynamics of An. arabiensis adults. Larvae of An. arabiensis were exposed to either cadmium chloride or copper nitrate, with larvae reared in untreated water serving as a control. Two laboratory strains (SENN: insecticide unselected, SENN-DDT: insecticide selected) and F1 larvae sourced from KwaZulu-Natal, South Africa, were exposed. The gut microbiota of the adults were sequenced using the Illumina Next Generation Sequencing platform and compared. Larval metal exposure affected alpha diversity, with a more marked difference in beta diversity. There was evidence of core microbiota shared between the untreated and metal-treated groups. Bacterial genera associated with metal tolerance were more prevalent in the metal-treated groups. Although larval metal exposure led to an increase in pesticide-degrading bacterial genera in the laboratory strains, this effect was not observed in the F1 population. In the F1 population, Plasmodium-protective bacterial genera were more abundant in the untreated group compared to the metal-treated group. This study therefore highlights the importance of considering the larval environment when searching for local bacterial symbionts for paratransgenesis interventions.

The Impact of Genetic Polymorphisms for Detecting Genotoxicity in Workers Occupationally Exposed to Metals: A Systematic Review.

The present study aims to provide a systematic review of studies on the essential and nonessential metal exposure at occupational level, genotoxicity, and polymorphisms and to answer the following questions: Are genetic polymorphisms involved in metal-induced genotoxicity? In this study, 14 publications were carefully analyzed in this setting. Our results pointed out an association between polymorphism and genotoxicity in individuals exposed to metals, because 13 studies (out of 14) revealed positive relations between genotoxicity and polymorphisms in xenobiotics metabolizing and DNA repair genes. Regarding the quality of these findings, they can be considered reliable, as the vast majority of the studies (12 out of 14) were categorized as strong or moderate in the quality assessment. Taken as a whole, occupational exposure to metals (essentials or not) induces genotoxicity in peripheral blood or oral mucosa cells. Additionally, professional individuals with certain genotypes may present higher or lower DNA damage as well as DNA repair potential, which will certainly impact the level of DNA damage in the occupational environment.