Metal Exposure Research Articles

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.

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.

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.

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.

Groundwater Contamination by Heavy Metals in Malaysia: Sources, Transport, and Remediation Strategies

Groundwater contamination by heavy metals is a pressing environmental concern, particularly in regions highly dependent on groundwater as a freshwater source. While Malaysia primarily relies on river water, certain states and islands depend on groundwater for their supply. Research on heavy metal contamination in Malaysia’s groundwater remains limited, making it crucial to study the distribution and mobility of contaminants to develop appropriate remediation strategies. In addition to natural sources, anthropogenic activities such as landfills, mining, and the use of fertilizers contribute significantly to heavy metal pollution in groundwater. Factors like rainfall, fluctuating groundwater levels, and low soil pH can exacerbate heavy metal leaching into aquifers. Various models and techniques, including 2D resistivity imaging and MODFLOW, are used to assess groundwater flow and contaminant transport. These models suggest that contaminant concentrations decrease with increased depth and radial distance from pollution sources such as landfills and mining areas. The health risks associated with heavy metal exposure through groundwater consumption are significant, necessitating effective remediation strategies. Phytoremediation is an economical solution for groundwater containing low concentrations of heavy metals, while permeable reactive barriers may be suitable for more complex cases, pending detailed site investigation. This review aims to examine the current state of knowledge on heavy metal contamination in Malaysia’s groundwater, focusing on sources, distribution patterns, and movement of pollutants. It also seeks to evaluate existing remediation methods, including phytoremediation and permeable reactive barriers, while identifying gaps in research, particularly concerning risk assessments and heavy metal speciation.

Occupational exposure assessment of heavy metals in human scalp hair among tannery workers in Bahir Dar, Ethiopia: Indication of pollution

Ethiopia, is one of the African countries, has immense potential for skins and hides for the leather industries, which will play a crucial role in converting nations into manufacturing-driven economies through industrialization. The chemicals applied in the tanning process are a serious concern for employees and the community if proper safety measures are not taken. The pollution status of employees working in Anbessa and Bahir Dar tannery factories was evaluated by collecting hair samples. After the hair samples washed with acetone, and deionized water, the hair samples were digested with 4 mL of HNO3 and 2 mL of HClO4 for 1:30 h at 250 °C. The levels of metals (Cr, Pb, Zn, Cu, Ni, and Cd) were subsequently analyzed using a Flame Atomic Absorption Spectrophotometer (FAAS). The mean concentrations of Cu, Ni, Zn, Pb, and Cr in the Anbessa tannery factory workers were 17.34–22.75, 16.38–35.03, 235.4–369.2, 30.46–67.31, and 97.56–189.18, respectively, in the various working departments of the factory. Similarly, the concentrations of Cu, Ni, Zn, Cd, Pb, and Cr in the hair of Bahir Dar tannery workers were 30.1–105.9, 17.88–62.20, 216.9–762.1, 0.35–5.21, 33.42–91.42, and 118.5–305.7, respectively. Chromium was found to be the most accumulated metal next to Zn with in both tannery workers that highlighted significant occupational health risks. The principal component analysis (PCA) analysis provide an insights into the interactions between occupational factors and metal exposure. In conclusion, the results of hair analysis from the employees of tannery factories indicates alarming levels of metal exposure, especially for zinc and chromium, which might pose health problems in long time exposure. Thus, it's critical to monitor occupational activities that can harm human health and the environment.

Surface water quality assessment and probable health threats of metal exposure in the Tano South Municipality, Ahafo, Ghana

The prime goal of this study was to assess the surface water quality and the associated health risks for residents in the Tano South Municipality, Ghana. The WHO drinking water criteria were compared with the findings of an analysis of eight surface waters for parameters such as physiochemical parameters, nutrient levels, and concentrations of selected metals. An evaluation was performed regarding the potential non-carcinogenic and carcinogenic risks associated with metal exposure by oral and dermal absorption. The estimated water quality index indicated that seven water samples were deemed unsuitable for human consumption, while one sample indicated very low water quality. The fluoride levels in all water samples were below the limit of detection, although it guards against dental caries. All of the water samples had mean concentrations of Cd and Fe above WHO guideline values, while one water sample had a Pb concentration that was higher than recommended. Principal component analysis showed that aside from the natural source, human-induced sources such as runoff of excess chemicals and soil erosion from adjacent farm soils were responsible for the substantial levels of contaminants in surface water samples. There was a possibility of non-carcinogenic consequences for children in seven out of eight water samples. However, cancer risk for Cd and Pb was not likely for adults and children in the study area. Findings serve as a representative case study for other districts and call on water managers to treat surface waters to guard against harmful health consequences and safeguard the designated buffer zones.

The Role of Copper in Alzheimer's Disease Etiopathogenesis: An Updated Systematic Review.

Alzheimer's disease (AD) is the most common cause of dementia and cognitive decline in the elderly. Although the etiology of AD is unknow, an increase in amyloid precursor protein (APP) leads to the toxic aggregation of Aβ plaques. Several factors, such as hypertension, diabetes, dyslipidemia, smoking, hormonal changes, and metal exposure, could increase the risk of developing AD. In this review, we will examine the role of copper (Cu) in the pathophysiology of AD, as well as the mechanisms involved in neurotoxicity and cognitive decline. This review was conducted in accordance with PRISMA guidelines. We performed a comprehensive literature analysis over the last ten years on AD and Cu. Only late-onset Alzheimer's disease was considered; only studies on elderly people of both sexes were included. A total of seven articles were picked for this review, three studies focused on non-ceruloplasmin-bound Copper (non-Cp-Cu) and four on ceruloplasmin-bound Copper (Cp-Cu). The results showed higher Cu concentrations in patients compared to healthy controls. Elevated concentrations of Cu may contribute to the progression of AD, potentially interacting with ATP7B mutations, oxidative stress (OS), and amyloid-β plaques. Future research is needed to provide more robust evidence and better characterize the relationship between AD and Cu.

Emission Factors, Chemical Composition and Ecotoxicity of PM10 from Road Dust Resuspension in a Small Inland City

Road dust resuspension in urban environments can contribute to high human exposure to metal(loid)s, polycyclic aromatic hydrocarbons, and other potentially toxic organic compounds. However, for many regions, information on loadings, emission factors and chemical profiles is lacking to accurately apply emission inventories and source apportionment models. In the present study, PM10 samples were collected with an in situ road dust sampler from eleven representative streets of Bragança, an inland city of the Iberian Peninsula, and were analysed for organic and elemental carbon by a thermal-optical technique, elemental composition by ICP-MS and ICP-OES, and ecotoxicity by a luminescence inhibition bioassay with Allivibrio fischeri. A global emission factor of 5.36 ± 2.35 mg veh−1 km−1 was obtained but in suburban areas the values reached twice the average. Total carbon accounted for 14.9 ± 6.8% of the PM10 mass, while element oxides represented the largest share (28.6 ± 18.7%). Very high enrichments were found for typical traffic-related elements such as Cu, Zn, S, Pb and Ni. The geochemical index Igeo further confirmed that road dust of the study region is extremely contaminated by elements mainly originated from tyre and brake wear. Although the total non-carcinogenic and carcinogenic risks associated with metal exposure were found to be low for both children and adults, the bioluminescence inhibition assay showed (eco)toxic responses for all samples, indicating that road dust resuspension may pose a significant human health and ecological threat.

Association between multiple metal exposure and bone mineral density among Chinese adults.

Previous studies about metal exposures and bone mineral density (BMD) have mainly focused on individual metals. The objective of this study was to explore the association of single and multiple metal exposures with BMD among Chinese adults. We recruited 2922 participants from Tongji Hospital in Wuhan, China. The urinary concentrations of 21 metals were measured by the inductively coupled plasma mass spectrometer. BMD was measured using dual-energy X-ray absorptiometry. We applied linear regression and Bayesian kernel machine regression (BKMR) to examine the association of single and multiple metal exposure with BMD, respectively. The linear regression model showed that cadmium (Cd) and strontium (Sr) were associated with lower BMD (all P-trend < 0.05). Compared with the lowest quantiles, the β (95% CI) of BMD in the highest quartile of Cd and Sr was - 0.032 (- 0.049, - 0.016) and - 0.033 (- 0.049, - 0.018), respectively. The BKMR results showed that co-exposure to 21 metals was negatively associated with BMD among the total participants and males. Our study suggested that exposure to multiple metals was negatively associated with BMD, particularly among males. More prospective studies are needed to identify these associations and reveal the underlying mechanisms.

Impact of metals exposure on lung function and serum club cell secretory protein among schoolchildren: A mixture and mediation analysis

Particulate matter (PM) and its harmful components are significant contributors to respiratory diseases and impaired lung function, especially in children. Club cell secretory protein (CC16) is a maker of lung epithelium or club cell injuries. To date, the relationship between metals related with PM and CC16 and lung function impairment has been overlooked in children. We enrolled 603 schoolchildren exposed to different levels of PM in China. We found per doubling increase, urinary thallium, and iron was associated with a 3.42 % (95 % CI: 0.01, 6.72) and 3.09 % (95 % CI: 0.55, 5.56) decrease of serum CC16, respectively, whereas urinary cadmium was associated with a 4.74 % (95 % CI: 1.29, 8.31) increase of serum CC16. The Bayesian kernel machine regression (BKMR) model confirmed these associations and showed a potential synergistic interaction between thallium and cadmium. Urinary metal mixtures were associated with lower CC16 when they were below the 35th percentile compared with their median. Serum CC16 mediated 11.47 % (95 % CI: 0.06, 45.00) of the association between urinary thallium and FEV1/FVC decline. The inverted U-shaped association with CC16 and the mediation role of CC16 on associations with lung function provide insight into the mechanisms underlying lung injury induced by metals related with PM.

Investigating the Spatial Patterns of Heavy Metals in Topsoil and Asthma in the Western Salt Lake Valley, Utah

Mining activities, particularly in large excavations like the Bingham Canyon Copper Mine in Utah, have been increasingly linked to respiratory conditions due to heavy-metal-enriched waste and dust. Operating continuously since 1906, the Bingham Canyon Copper Mine contributes 4.4% of the Salt Lake Valley PM2.5 pollution. However, the extent of its contributions to larger-sized particulate matter (PM10) dust, soil and water contamination, and human health impacts is largely unknown. Aerosol optical depth data from Sentinel-2 imagery revealed discernible dust clouds downwind of the mine and smelter on non-prevailing-wind days, suggesting potential heavy metal dispersion from this fugitive dust and subsequent deposition to nearby surface soils. Our analysis of topsoils from across the western Salt Lake Valley found mean arsenic, copper, lead, and zinc concentrations to be well above global background concentrations. Also, the minimum values for arsenic and maximum values for lead were well above the US EPA regional screening levels for residential soils. Thus, arsenic is the metal of greatest concern for impacts on human health. Elevated concentrations of all metals were most notable near the mine, smelter, and tailings pond. Our study linked these elevated heavy metal levels to regional asthma outcomes through cluster analysis and distance-related comparison tests. Significant clusters of high asthma rates were observed in regions with elevated topsoil heavy metal concentrations, impacting both low- and high-income neighborhoods. The findings of this preliminary study suggest that the mine, smelter, and recent construction activities, especially on lands reclaimed from former tailings ponds, could be contributing to atmospheric dust containing high levels of heavy metals and exacerbating asthma outcomes for residents. However, the methods used in the study with aggregated health outcome data cannot determine causal links between the heavy metal contents of soil and health outcomes; they can only point to potential links and a need for further investigation. Such further investigation should involve individual-level data and control for potential confounding factors, such as socioeconomic status, access to healthcare, and lifestyle factors, to isolate the effect of metal exposures on asthma outcomes. This study focused on atmospheric deposition as a source of heavy metal enrichment of topsoil. However, future research is also essential to assess levels of heavy metals in subsoil parent materials and local surface and groundwaters to be able to assess the links between the sources or methods of soil contamination and health outcomes.