Current research provides limited evidence for connections between metal exposure, as an emerging environmental risk factor, and obstructive sleep apnea (OSA) risk. This study aimed to examine the associations between blood and urine metal exposure and OSA risk. This cross-sectional study recruited participants and extracted data from the 2017-2020 round survey of the National Health and Nutrition Examination Survey. OSA was ascertained using the STOP questionnaire. Eight metals in blood samples were detected in 3,857 participants, and seven metals in urine samples from 1,902 participants. The combined effects of blood or urinary metal mixtures on OSA were assessed using Weighted Quantile Sum (WQS) regression and Quantile-based g-computation (Qgcomp) models. Odds ratio (OR) with 95% confidence interval (CI) was estimated using a weighted logistic regression model. Restricted cubic spline (RCS) models were applied to display the nonlinear associations. Both the WQS model (OR: 1.362, 95% CI: 1.123-1.652) and the Qgcomp models (OR: 1.259, 95% CI: 1.070-1.483) revealed that urinary metal mixtures were positively associated with OSA, with mercury and nickel contributing the highest weights. For each metal, RCS models were applied but significant nonlinear associations were only observed between blood mercury and urinary chromium and OSA risk. In single-metal models, most individual metals did not show significant associations after adjustment. This study identified nonlinear associations between blood mercury and urinary chromium concentrations and OSA risk, and exposure to mixtures of urinary metals was associated with an increased OSA risk.

Exposure to heavy metals has been implicated in insulin resistance (IR), yet the mechanisms remain unclear. Systemic inflammation may link metal exposure to metabolic outcomes. We analyzed 3042 U.S. adults from NHANES 2021-2023. Blood lead, cadmium, mercury, selenium, and manganese were examined in relation to IR (HOMA-IR), with high-sensitivity C-reactive protein (hs-CRP) as the inflammatory mediator. We used survey-weighted regression, Baron-Kenny mediation, and weighted quantile sum (WQS) regression for the mixture, stratified by sex; sensitivity analyses additionally adjusted for body mass index (BMI) and smoking. In primary models, lead, cadmium, and mercury were inversely associated with HOMA-IR (lead β = -0.259), as was a WQS mixture dominated by these metals, and hs-CRP significantly mediated several associations. After additional adjustment for BMI and smoking, the inverse single-metal and mixture associations remained significant but were attenuated by roughly half, indicating substantial adiposity confounding. hs-CRP continued to mediate a smaller but significant share (roughly 10% to 30%, vs. 25% to 43% before adjustment). The positive manganese association did not survive BMI adjustment and is not robust. Mediation was larger in females and younger adults. In a nationally representative sample, blood lead, cadmium, and mercury, individually and as a mixture, were inversely associated with insulin resistance, with hs-CRP mediating a smaller but significant share after adjustment for adiposity. Because the associations are substantially attenuated by BMI and the design is cross-sectional, reverse causation is plausible. These findings are hypothesis-generating and motivate prospective studies.

Exposure to mercury (Hg), cadmium (Cd) and lead (Pb) in early life is associated with negative health effects. Pregnancy and lactation are particularly sensitive periods as stored maternal body burdens may be mobilized and transported to the child over placenta and in breast milk. The objective of the study was to evaluate relations between maternal and infant whole blood concentrations of Hg, Cd and Pb in a longitudinal study from pregnancy week 18 to 6 months postpartum. Whole blood Hg, Cd and Pb were measured in pregnancy week 18, 28 and 36, as well as 6 weeks, 4 and 6 months postpartum in 114 Norwegian pregnant and lactating women and their infants at age 6 months. Data on maternal nutrition and lifestyle factors, and months of exclusive breastfeeding were collected. Maternal whole blood Hg and Pb during pregnancy and postpartum were significant positive predictors for whole blood Hg and Pb in infants at six months, while no associations were observed for whole blood Cd. The majority of the infants were breastfed with a mean duration of exclusive breastfeeding of 3.8 (SD 1.5) months. Despite a substantial increase in maternal whole blood Hg, Cd and Pb concentrations postpartum, no associations were seen between infant heavy metal status and months of exclusive breastfeeding, indicating that placental transfer may be the major source of early life exposure to Hg and Pb. Public health interventions should focus on reducing the exposure of heavy metals to females from a very young age.

Association between blood mercury levels and estimated glomerular filtration rate in a Spanish population with high fish consumption: A cross-sectional study.

Bioaccumulation of trace elements by Leach's storm-petrels (Hydrobates leucorhous) in the North and South Atlantic Ocean during the non-breeding period.

Stroke occupies an important position in the global disease burden, but the combined effect of heavy metal exposure and the inflammatory marker C-reactive protein (CRP) on stroke remains unclear. Based on the National Health and Nutrition Examination Survey, this study explores the association between blood lead, blood cadmium, blood mercury, CRP, and the risk of stroke. A total of 8297 American adults aged 20 years and older were included in the National Health and Nutrition Examination Survey. Standardized questionnaires were used to collect stroke history and covariates such as age, gender, race, education, income poverty ratio, body mass index, smoking, drinking, hypertension, and diabetes; whole blood cadmium, lead, mercury, and serum CRP were measured. Weighted multivariate logistic regression was used to evaluate the relationship between heavy metal exposure and CRP outcomes; receiver operating characteristic curves were constructed to compare model performance; and a 3D interaction graph was used to evaluate the synergistic effect of plumbum and CRP. Baseline characteristics: the stroke group’s median age (69 years) was significantly higher than the non-stroke group’s (33 years). Stroke patients had higher blood lead, CRP, hypertension/diabetes rates, and body mass index, but lower blood mercury, education, income levels (P < .05). After adjustment, each unit increase in blood lead and CRP increased the risk of stroke by 7% (odds ratio [OR] = 1.07, 95% confidence interval: 1.00–1.14) and 19% (OR = 1.19, 95% confidence interval: 1.07–1.32), respectively; blood cadmium and mercury had no significant association. The Receiver Operating Characteristic curves showed model 2 (area under the curve = 0.80) outperformed model 1 (area under the curve = 0.64). In age subgroups, cadmium affected the 40- to 60-year age group (OR = 1.39); lead was positively and mercury negatively correlated with the ≥60 group; CRP rose in both groups. The 3D graph indicated that stroke risk increased when both blood lead and CRP levels were high. Blood lead and CRP are independent stroke risk factors. Each unit rise in blood lead raises stroke risk by 7%, and each unit increase in CRP raises it by 19%. When both are high, stroke risk may further rise, especially in the elderly. Clinically, regular monitoring of these factors aids in stroke risk assessment. For high-risk groups, including these in routine screening enables early risk identification.

Heavy metal exposure has been associated with various diseases. The purpose of this study was to determine the single and mutually adjusted associations between blood heavy metals and cognitive function in older adults. This observational study utilizes data from the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014 and involved 1460 participants aged ≥ 60 years. The concentrations of blood lead (Pb), cadmium (Cd), mercury (Hg), selenium (Se), and manganese (Mn) were measured using inductively coupled plasma mass spectrometry (ICP-MS). Cognitive function was assessed using the Immediate Recall Test (IRT), delayed recall test (DRT), animal fluency test (AFT), and digit symbol substitution test (DSST). Mutually adjusted linear regression models, restricted cubic spline (RCS) analyses, and subgroup analyses were performed to evaluate individual and mutually adjusted associations between blood metal concentrations and cognitive function. Multiple linear regression analysis revealed an inverse association between Cd concentrations and cognitive scores (β=-2.698, 95% CI: -4.842, -0.554). Blood Se levels were positive associations with cognitive scores (β = 0.049, 95% CI: 0.022, 0.076) and all four cognitive domains. The RCS showed that the dose-response association between Cd and cognitive scores appeared to be linear (P-nonlinear = 0.566), while Se exhibited a left-skewed inverted U-shaped curve with cognitive scores (P-nonlinear = 0.013). A high concentration of Cd is strongly associated with cognitive decline. However, the protective effect of Se on cognitive function plateaus after reaching a certain concentration. These findings may have significance for the development of interventions aimed at alleviating cognitive impairment.

First evidence of arsenic and mercury bioaccumulation and associated genotoxic effects in Caiman crocodilus in a mining-affected river in the Colombian Pacific.

BackgroundDental caries remains a major public health concern among children and adolescents. While established risk factors such as diet and oral hygiene are well recognized, the association between environmental heavy metal exposure and pediatric dental caries is not fully understood. This study examined the relationship between blood heavy metal concentrations and dental caries in a nationally representative pediatric population.MethodsData from 15,194 participants aged 5–19 years were obtained from the National Health and Nutrition Examination Survey (NHANES). Dental caries was assessed using the DMFT/S index. Blood lead, cadmium, and mercury concentrations were measured by inductively coupled plasma mass spectrometry. Multivariable logistic regression models were used to evaluate associations after adjustment for sociodemographic, nutritional, and hematological covariates. Multiple machine learning models were constructed to assess predictive performance, and SHAP values were applied to interpret feature importance.ResultsHigher blood concentrations of lead, cadmium, and mercury were independently associated with increased odds of dental caries (lead: OR = 1.10, 95% CI: 1.02–1.18; cadmium: OR = 1.18, 95% CI: 1.10–1.27; mercury: OR = 1.14, 95% CI: 1.06–1.22). Subgroup analyses demonstrated heterogeneity by age and socioeconomic status, with stronger associations for cadmium observed among adolescents and higher-income groups. Among the machine learning models, XGBoost showed the best predictive performance (AUC = 0.75), with cadmium ranking as the most influential feature.ConclusionBlood heavy metal concentrations were significantly associated with dental caries in children and adolescents, suggesting that environmental exposure may be an important correlate of pediatric caries risk.

BackgroundCardiovascular diseases (CVDs) are a primary cause of mortality in the elderly. Exposure to heavy metals such as lead, cadmium, and mercury has been suggested to increase CVD risk by inducing reactive oxygen species and inflammatory responses. The elderly are particularly susceptible to heavy metal exposure, which may increase their CVD risk. Despite this potential risk, evidence specifically focusing on the association between blood heavy metal levels and high-sensitivity C-reactive protein (hsCRP), a key predictor of CVDs, in the elderly remains limited. Therefore, the present study aimed to assess the relationship between blood lead, mercury, and cadmium concentrations and hsCRP in the elderly.MethodsWe analyzed 884 subjects (385 men, 499 women) aged 65 years and older without CVD history from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016–2017. Because KNHANES is a two-stage stratified clustered sample, all analyses applied stratum, cluster, and weight. Estimated geometric means (GMs) of hsCRP across demographic factors and heavy metal quartiles were compared using a complex samples general linear model (CSGLM). The association between blood heavy metals and hsCRP was examined using CSGLM, adjusting for age, sex, body mass index, estimated glomerular filtration rate, smoking status, alcohol consumption, education, physical activity, monthly income, and underlying diseases.ResultsThe estimated GM of hsCRP differed significantly by blood lead quartile (p = 0.035) and showed a significant increasing trend (p for trend = 0.019). In CSGLM analysis, elevated blood lead concentrations were significantly associated with increased hsCRP (β = 0.176, p = 0.032) after adjustment. However, blood mercury and cadmium concentrations showed no significant associations with hsCRP.ConclusionsThe observed association between blood lead concentrations and hsCRP suggests that elevated blood lead may contribute to increased CVD risk in the elderly. Given the susceptibility of this population, subsequent investigations are warranted to confirm this association and develop preventive strategies.

Tinnitus is a common symptom among adults in the United States. Increasing evidence indicates that prolonged exposure to heavy metals and excessive intake of trace elements from environmental pollution can increase the likelihood of hearing loss. Although studies have reported associations between heavy metals and hearing loss, the relationship between heavy metals and tinnitus remains uninvestigated. After accounting for the complex survey design, we assessed cross-sectional data on blood lead, cadmium, mercury, selenium, and manganese levels in 4950 participants from the National Health and Nutrition Examination Survey database (2012–2018). We used weighted multivariate logistic regression, weighted multivariate linear regression, restricted cubic spline regression, and receiver operating characteristic curve analysis to investigate the relationship between these 5 blood heavy metals and tinnitus. Subgroup and sensitivity analyses were performed to evaluate consistency across subgroups and the robustness of the findings. Compared with the lowest quartile (Q1), the odds of tinnitus were significantly higher in the highest quartiles of blood lead (odds ratio = 1.63, 95% CI: 1.23–2.16) and cadmium (odds ratio = 1.32, 95% CI: 1.02–1.70). Restricted cubic spline curves indicated a nonlinear association between the odds of tinnitus and blood lead, cadmium, mercury, and selenium levels. However, no nonlinear relationship was found regarding blood manganese levels (P for nonlinear = .1334; P total = .2446). Subgroup analyses suggested that sex and ethnicity may modify the strength of the association between blood cadmium and blood lead levels with tinnitus prevalence. The association between blood mercury levels and tinnitus was highly homogeneous and stable across all examined demographic and clinical subgroups. The link between blood selenium levels and tinnitus was more pronounced among males, non-Hispanic whites, and individuals aged 40 to 60 years. Blood lead, cadmium, mercury, and selenium levels were significantly associated with the prevalence of tinnitus. High levels of these metals may be potential indicators for tinnitus management.

Schoolchildren's exposure to potentially toxic metals/metalloids and cognitive impairments in communities of the Brazilian Amazon new agricultural frontiers.

Environmental exposure to heavy metals during pregnancy may adversely impact fetal development, particularly in low- and middle-income countries (LMICs) with limited environmental regulation. This study aimed to assess the relationship between maternal exposure to lead (Pb), cadmium (Cd), and mercury (Hg) and fetal growth parameters in an Indonesian population. A cross-sectional study of 127 pregnant women in their second trimester was conducted. Maternal characteristics and exposure sources were obtained via structured questionnaires. Blood concentrations of Pb, Cd, and Hg were measured using inductively coupled plasma mass spectrometry (ICP-MS). Fetal biometry was assessed by ultrasonography, and z-scores were calculated. Generalized additive models (GAMs) and linear mixed models (LMMs) with restricted cubic splines (RCS) were used to evaluate non-linear associations, adjusting for maternal age and secondhand smoke exposure. Among the 127 pregnant women, the median age was 30 years (range: 20-40 years), and the median blood concentrations of Pb, Cd, and Hg were 6.6, 0.022, and 0.021 µg/L, respectively. Fetal growth Z-scores were as follows: BPD_z = -0.48 (range: -2.5 to 2.5), HC_z = -0.38 (range: -2.0 to 2.0), AC_z = -0.56 (range: -2.5 to 2.0), FL_z = -0.62 (range: -2.5 to 2.5), and EFW_z = -0.75 (range: -3.0 to 2.0). Using linear mixed models with restricted cubic splines (RCS), Cd and Hg exposures were significantly associated with increased fetal Z-scores (Cd: β = 1.48, P < .001; Hg: β = .99, P < .001), while Pb showed a negative association (β = -.93, P < .001). Non-smokers exhibited more favorable fetal growth responses compared to those exposed to secondhand smoke. Maternal exposure to heavy metals showed non-linear effects on fetal growth. The findings underscore the need for environmental health monitoring and preventive measures during pregnancy.

Mercury (Hg) exposure from artisanal and small-scale gold mining (ASGM) remains a major public health concern, particularly in communities where mercury amalgamation is still widely practiced. Chronic mercury exposure is known to induce oxidative stress and may interfere with detoxification pathways involving glutathione S-transferase enzymes, including GSTP1 and GSTT1. This study aimed to assess blood mercury levels and PCR-based GSTP1 and GSTT1 gene profiles among artisanal gold miners in Central Java. A cross-sectional descriptive study was conducted using whole blood samples from 10 adult males, consisting of 5 artisanal gold miners and 5 non-miner controls. Blood mercury concentrations were measured spectrophotometrically, while GSTP1 and GSTT1 gene profiles were evaluated using polymerase chain reaction (PCR). Blood mercury levels in miners ranged from 20.244 to 67.987 µg/L, exceeding the recommended reference value of &lt;20 µg/L, whereas control subjects showed levels below the threshold. PCR analysis demonstrated expected GSTP1 and GSTT1 bands in all control samples. In contrast, miner samples showed variations in PCR band patterns, including larger than expected amplicons for GSTP1 and absence of GSTT1 amplification in two samples, which may indicate altered gene profiles associated with mercury exposure. In conclusion, artisanal gold miners exhibited elevated blood mercury levels alongside variations in GSTP1 and GSTT1 PCR profiles. Although the small sample size limits definitive genetic interpretation, these findings suggest that combined biomonitoring of mercury burden and detoxification-related gene profiles may provide useful preliminary indicators for assessing susceptibility to mercury exposure in ASGM settings.

Exposure to harmful trace elements can lead to their accumulation in various biological substrates, resulting in the development of acute and chronic diseases in humans and animals. The knowledge of bioaccumulation of trace elements in different biological substrates could provide important information on exposure to trace elements through the use of sentinel animals. The aim of this research was to study the potential bioaccumulation of various trace elements (Arsenic-As, Cobalt-Co, Nickel-Ni, Lead-Pb, Mercury-Hg and Titanium-Ti) in goat blood and hair and their relationship with haematological biomarkers. Hair was collected from 25 non-pregnant and non-lactating clinical healthy goats aged between 2 and 3 years reared in Sicily, to determine trace elements concentration by means of inductively coupled plasma mass spectrometer (ICP-MS). Blood in duplicate was collected at the same time to determine trace element concentration and haematological profile. A paired t-test and multiple regression analysis was performed to evaluate the relationship among As, Co, Ni, Pb, Hg and Ti and blood and hair, together with their relationship with haematological parameters, respectively. Statistical analysis showed a significant higher concentration of As (p < 0.0001) and Pb (p < 0.0001) in blood compared to hair and higher concentration of Co (p < 0.0001), Ni (p < 0.0001), Hg (p < 0.0001), and Ti (p < 0.0001) in hair compared to blood. Blood As and Ti showed a positive correlation with HGB (r = 0.48; p < 0.01; r = 0.52; p < 0.01). Blood Pb and Ti showed a positive correlation with HCT (r = 0.52; p < 0.01; r = 0.52; p < 0.01) and a negative correlation was observed for blood Co and WBC (r = -0.45; p < 0.01). The analysis of the results clearly indicates a strong correlation between the bioaccumulation of certain trace elements and some haematological parameters. These results should be examined thoroughly in goats to understand the significance of haematological factors in productive and reproductive activities.

Mercury (Hg) is a global contaminant that biomagnifies in marine food webs. Seabirds can serve as valuable bioindicators of marine Hg pollution due to their high trophic positions and broad distributions. However, the biological and spatial drivers of variation in seabird Hg levels remain unclear, and few studies have validated whether seabird-derived estimates of the spatial distribution of Hg are consistent with predictions from biogeochemical-ocean models. We conducted a global meta-analysis of total Hg (THg) concentrations in adult seabird blood. Based on our own fieldwork and a literature review, we compiled 478 mean THg values from 108 species representing >11,000 individuals. Blood THg increased in species feeding at higher trophic levels, with larger body mass, and those more likely to consume mesopelagic prey in oceanic waters. Additionally, blood THg might further increase in regions with low chlorophyll-a level, likely due to greater methylmercury uptake in areas with low-productivity. We subsequently developed models to predict global spatial variation in seabird blood THg, either from all species or only epipelagic prey feeders. Only our epipelagic prey feeder-based model showed a weak significant positive correlation with THg in particulate organic matter from biogeochemical-ocean models. However, the low correlation coefficient (r=0.23) indicates potential discrepancies between the two models. We suggest that future studies adopt our integrative approach, combining biological data and large-scale modeling, to improve our understanding of global marine Hg pollution. Together, these findings clarify the biological and environmental drivers of Hg exposure in seabirds and highlight the value of seabirds for global monitoring of marine Hg pollution.

BackgroundSmelter workers and chimney sweepers may be exposed to heavy metals via particulate matter through airways and skin uptake. We hypothesized that these workers have higher blood concentrations of arsenic, cadmium, chromium, lead, and mercury compared to an office-worker group. Furthermore, we hypothesized that their concentrations increased cross-week despite the use of properly fitted respiratory protective equipment (RPE). Our aim was to uncover workers’ general heavy metal concentrations and cross-week changes to provide further insight into industrial occupational exposure.MethodsWe conducted a cross-sectional study with 2 repeated measures. We quantified whole blood arsenic, cadmium, chromium, lead, and mercury 4 d apart. Participants answered a standardized questionnaire and log scheme on work exposure. Samples were analyzed using inductively coupled plasma mass spectrometry, and we used Wilcoxon's signed-rank test and multiple linear regression to assess heavy metal differences across the 4-d workweek and occupational groups.ResultsOut of 226 participants (99 smelter workers, 80 chimney sweepers, and 47 office workers), 185 participants provided blood samples. The final dataset included 151 participants. Overall, heavy metal concentrations were below Mayo Clinic's cutoff concentrations. Multiple linear regression analysis with confounders did not show higher concentrations of heavy metals in the exposed occupations compared to office workers. Instead, we found statistically significant lower chromium in smelter workers. Sensitivity power analysis showed that our nonsignificant findings in the other metals were underpowered. Wilcoxon's signed rank test did not show cross-week increase.ConclusionsIn our population of chimney sweepers and smelter workers with high percentage use of RPE, occupational exposure to heavy metals does not seem to increase workers blood heavy metals; lifestyle factors seem more important. Further studies with higher number of participants are warranted to ensure our findings.

BackgroundHeavy metals are recognized neurotoxicants implicated in depression, yet limited research examines combined metal impacts. This study aimed to investigate the joint effect of heavy metals on depression and identify key contributors within the mixture.MethodsAnalyzing National Health and Nutrition Examination Survey data, adults with complete data on nine urinary metals (antimony, barium, cadmium, cobalt, cesium, molybdenum, lead, thallium, and tungsten), three blood metals (cadmium, mercury, and lead), depression status, and key covariates were assessed via four methods (multivariate logistic regression, restricted cubic spline (RCS) regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR)) to evaluate metal–depression associations.ResultsAmong 8814 participants (731 with depression), those with depression showed higher urine and blood cadmium levels, but lower blood mercury and urine thallium levels compared to controls. Adjusted analyses linked elevated urine antimony (OR = 1.34, p = 0.029) and tungsten (OR = 1.42, p = 0.008) to increased depression risk, while higher urine thallium (OR = 0.52, p < 0.001) and blood mercury (OR = 0.7, p = 0.005) reduced risk. RCS analysis revealed nonlinear relationships between depression and urine cadmium (p = 0.004), cobalt (p = 0.005), lead (p = 0.024), antimony (p < 0.001), tungsten (p < 0.001), as well as blood cadmium (p < 0.001) and mercury (p < 0.001). The mixture analysis revealed both positive and negative exposure–response relationships, which were, respectively, dominated by urinary tungsten (29.3% weight in the WQS index) and blood mercury (44% weight). BKMR analysis confirmed multi-metal co-exposure elevates depression risk, and urinary barium showed the highest BKMR-derived posterior inclusion probability (PIP = 0.448).ConclusionOur findings link heavy metal mixtures to depression, identifying tungsten and antimony as risk contributors, versus inverse associations for mercury and thallium, with barium as a key interactive factor. Further studies are needed to validate these metal-specific impacts and uncover additional depression-linked metals.Graphical abstractSupplementary InformationThe online version contains supplementary material available at 10.1186/s40001-026-03850-x.

Occupational mercury poisoning is a significant work-related illness due to that mercury vapor and its compounds can enter the human body and cause systemic damage. Therefore, regular blood mercury monitoring is essential for occupationally exposed individuals. Among existing detection methods, mercury analyzers are widely used for direct blood mercury determination. Despite the utility of direct mercury analyser (DMA), their application to blood samples is often compromised by limitations such as method instability and mercury carryover. To address these challenges, this study introduces a DL-cysteine-assisted determination method. It is based on the principle that DL-cysteine forms stable complexes with mercury in blood, thereby mitigating container adsorption and memory effects. Specifically, DL-cysteine solution was incorporated into both the mercury calibration standards and the blood samples within the sample boat prior to analysis using a DMA. The limit of detection was 0.5 μg/L, and the limit of quantification was 1.5 μg/L. Method accuracy, evaluated by spiked recovery, ranged from 99.14% to 99.92%. Experiments demonstrated that the stability, recovery, and repeatability of the direct mercury determination method were improved by introducing DL-cysteine, which offers practical value in enhancing the performance of direct mercury determination methods and is suitable for routine blood mercury monitoring.

Determinants of human hair mercury, blood mercury, blood selenium, and plasma omega-3 fatty acid levels within northern Canada.