Environmental exposure to low-level lead (Pb) co-occurring with other neurotoxicants in early life and neurodevelopment of children

Sex-specific associations of a ferroalloy metal mixture with motor function in Italian adolescents

Background

Motor function is critical for children's health, yet remains an understudied neurodevelopmental domain. Exposure to metals has been linked with motor function, but no study has examined the joint effects of metal mixtures.

Methods

We evaluated cross-sectional associations between a metal mixture and motor function among 569 adolescents (10-14 years old) living near the ferroalloy industry. Concentrations of blood lead, hair manganese, hair copper, and hair chromium were quantified using inductively coupled plasma mass spectrometry. Neuropsychologists administered multiple fine motor function assessments: pursuit aiming, finger tapping, visual reaction time (VRT), and subtests from the Luria Nebraska battery. We estimated associations between motor function and the metal mixture using quantile-based g-computation and multivariable linear regression, adjusting for child age, sex, and socioeconomic status. We explored sex-specific associations in stratified models.

Results

Associations between the metal mixture and motor function were mostly null but were modified by sex. We observed a beneficial association among females: a quartile increase in all metals in the mixture was associated with a 2.6% faster average response time on the VRT (95% confidence interval [CI] = -4.7%, -0.5%), driven by Cu and Cr. In contrast, this association was adverse among males (ß = 1.5% slower response time [95% CI = -0.7%, 3.9%]), driven by Cu and Mn.

Conclusions

Results suggest that males may be more susceptible to the adverse effects of metal exposure on motor function during adolescence than females. Future studies, particularly prospective study designs, are warranted to further understand the associations of metal mixtures with motor function.

Commercially available mouthguards: Unearthing trace elements for the first time

The use of mouthguards is advocated by the American Dental Association for orofacial injury prevention and teeth protection. However, the chemical environment in the mouth may cause harmful substances within the mouthguard's polymer material to leach out and be absorbed by the user. Considering this, the present study for the first time analyzed commercially available mouthguards and disclosed the presence of trace elements. Specifically, an analytical method was developed based on closed-vessel microwave-assisted digestion and plasma-based atomic spectrometry for determining toxic trace elements in mouthguard samples. Initially, 75 elements were assessed and, thereafter, quantified cadmium (Cd), copper (Cu) and lead (Pb) in each sample by inductively coupled plasma mass spectrometry (ICP-MS). Method validation was carried out by analyzing a certified reference material of Low-Density Polyethylene, and by addition and recovery experiments. Results for copper were further validated by ICP optical emission spectrometry (ICP-OES). While most samples exhibited elemental levels beneath the method's limit of quantification, Cd, Cu and Pb were detected in four samples. Remarkably, one sample had Cu levels exceeding safe limits by 109 times, highlighting potential toxicity risks. This initial research underscores the need for stricter contamination control in mouthguard materials to minimize potentially health hazards.

Associations of maternal blood metal concentrations with plasma eicosanoids among pregnant women in Puerto Rico

BACKGROUND/AIM

Heavy metals are known to induce oxidative stress and inflammation, and the association between metal exposure and adverse birth outcomes is well established. However, there lacks research on biomarker profiles linking metal exposures and adverse birth outcomes. Eicosanoids are lipid molecules that regulate inflammation in the body, and there is growing evidence that suggests associations between plasma eicosanoids and pregnancy outcomes. Eicosanoids may aid our understanding of etiologic birth pathways. Here, we assessed associations between maternal blood metal concentrations with eicosanoid profiles among 654 pregnant women in the Puerto Rico PROTECT birth cohort.

METHODS

We measured concentrations of 11 metals in whole blood collected at median 18 and 26 weeks of pregnancy, and eicosanoid profiles measured in plasma collected at median 26 weeks. Multivariable linear models were used to regress eicosanoids on metals concentrations. Effect modification by infant sex was explored using interaction terms.

RESULTS

A total of 55 eicosanoids were profiled. Notably, 12-oxoeicosatetraenoic acid (12-oxoETE) and 15-oxoeicosatetraenoic acid (15-oxoETE), both of which exert inflammatory activities, had the greatest number of significant associations with metal concentrations. These eicosanoids were associated with increased concentrations of Cu, Mn, and Zn, and decreased concentrations of Cd, Co, Ni, and Pb, with the strongest effect sizes observed for 12-oxoETE and Pb (β:-33.5,95 %CI:-42.9,-22.6) and 15-oxoETE and Sn (β:43.2,95 %CI:11.4,84.1). Also, we observed differences in metals-eicosanoid associations by infant sex. Particularly, Cs and Mn had the most infant sex-specific significant associations with eicosanoids, which were primarily driven by female fetuses. All significant sex-specific associations with Cs were inverse among females, while significant sex-specific associations with Mn among females were positive within the cyclooxygenase group but inverse among the lipoxygenase group.

CONCLUSION

Certain metals were significantly associated with eicosanoids that are responsible for regulating inflammatory responses. Eicosanoid-metal associations may suggest a role for eicosanoids in mediating metal-induced adverse birth outcomes.

Chronic Lead Exposure in Adult Mice: Associations with miR-671/CDR1as Regulation, NF-κB Signaling, and Alzheimer's Disease-like Pathology

Long-term exposure to lead (Pb) can result in chronic damage to the body through accumulation in the central nervous system (CNS) leading to neurodegenerative diseases, such as Alzheimer's disease (AD). This study delves into the intricate role of miR-671/CDR1as regulation in the etiology of AD-like lesions triggered by chronic Pb exposure in adult mice. To emulate the chronic effects of Pb, we established a rodent model spanning 10 months of controlled Pb administration, dividing 52 C57BL/6J mice into groups receiving varying concentrations of Pb (1, 2, or 4 g/L) alongside an unexposed control. Blood Pb levels were monitored using serum samples to ensure accurate dosing and to correlate with observed toxicological outcomes. Utilizing the Morris water maze, a robust behavioral assay for assessing cognitive functions, we documented a dose-dependent decline in learning and memory capabilities among the Pb-exposed mice. Histopathological examination of the hippocampal tissue revealed tell-tale signs of AD-like neurodegeneration, characterized by the accumulation of amyloid plaques and neurofibrillary tangles. At the molecular level, a significant upregulation of AD-associated genes, namely amyloid precursor protein (APP), β-secretase 1 (BACE1), and tau, was observed in the hippocampal tissue of Pb-exposed mice. This was accompanied by a corresponding surge in the protein levels of APP, BACE1, amyloid-β (Aβ), and phosphorylated tau (p-tau), further implicating Pb in the dysregulation of these key AD markers. The expression of CDR1as, a long non-coding RNA implicated in AD pathogenesis, was found to be suppressed in Pb-exposed mice. This observation suggests a potential mechanistic link between Pb-induced neurotoxicity and the dysregulation of the CDR1as/miR-671 axis, which warrants further investigation. Moreover, our study identified a dose-dependent alteration in the intracellular and extracellular levels of the transcription factor nuclear factor-kappa B (NF-κB). This finding implicates Pb in the modulation of NF-κB signaling, a pathway that plays a pivotal role in neuroinflammation and neurodegeneration. In conclusion, our findings underscored the deleterious effects of Pb exposure on the CNS, leading to the development of AD-like pathology. The observed modulation of NF-κB signaling and miR-671/CDR1as regulation provides a plausible mechanistic framework for understanding the neurotoxic effects of Pb and its potential contribution to AD pathogenesis.

Geochemical evaluation, ecological and human health risk assessment of potentially toxic elements in urban soil, Southern India

Roadside soil contamination is mostly caused by human-caused pollutant deposition. PTEs are among the many substances that are harmful for both humans and the environment. PTE concentrations in roadside soil in Chennai, southern India, have been determined in this study. To evaluate the seriousness of the threats, more environmental and geochemical indices have been applied. 83 soil samples have been obtained from the study regions and focusing on important roads. Elemental analysis has been analyzed with ED-XRF and sieve-filtered samples focused on PTEs such as arsenic, barium, cobalt, chromium, copper, iron, potassium, nickel, lead, thorium, titanium, zinc, and uranium. Significant metallic variations have been found in soil samples around roads by the investigation. The elements this study examined section ascending in the following sequence: Fe > Ti > Zn > Cr > Pb > Cu > Ni > Th > As > U > K. In the research area, the CD classification denotes high contamination, whereas the CF indices show mild to significant pollution. PLI indicates moderate to high pollution, whereas EF suggests excessive enrichment. Igeo demonstrates a range from uncontaminated to highly contaminated. PERI showed high levels in the northern study region, whereas GUFI shows several hot spots indicating moderate to severe pollution. The Hazard Index (HI) values for all metals were less than one, demonstrating the absence of non-carcinogenic risks for both adults and children. Multivariate data show natural and anthropogenic PTEs in roadside soil. In addition, a soil quality monitoring system is needed to mitigate continual contamination risks.

The impact of psychosocial adversity on brain and behaviour: an overview of existing knowledge and directions for future research

Environmental experiences play a critical role in shaping the structure and function of the brain. Its plasticity in response to different external stimuli has been the focus of research efforts for decades. In this review, we explore the effects of adversity on brain's structure and function and its implications for brain development, adaptation, and the emergence of mental health disorders. We are focusing on adverse events that emerge from the immediate surroundings of an individual, i.e., microenvironment. They include childhood maltreatment, peer victimisation, social isolation, affective loss, domestic conflict, and poverty. We also take into consideration exposure to environmental toxins. Converging evidence suggests that different types of adversity may share common underlying mechanisms while also exhibiting unique pathways. However, they are often studied in isolation, limiting our understanding of their combined effects and the interconnected nature of their impact. The integration of large, deep-phenotyping datasets and collaborative efforts can provide sufficient power to analyse high dimensional environmental profiles and advance the systematic mapping of neuronal mechanisms. This review provides a background for future research, highlighting the importance of understanding the cumulative impact of various adversities, through data-driven approaches and integrative multimodal analysis techniques.

Prenatal exposure to metal mixtures and childhood temporal processing in the PROGRESS Birth Cohort Study: Modification by childhood obesity

Children are frequently exposed to various biological trace metals, some essential for their development, while others can be potent neurotoxicants. Furthermore, the inflammatory and metabolic conditions associated with obesity may interact with and amplify the impact of metal exposure on neurodevelopment. However, few studies have assessed the potential modification effect of body mass index (BMI). As a result, we investigated the role of child BMI phenotype on the relationship between prenatal exposure to metal mixtures and temporal processing. Leveraging the PROGRESS birth cohort in Mexico City, children (N = 563) aged 6-9 years completed a Temporal Response Differentiation (TRD) task where they had to hold a lever down for 10-14 s. Blood and urinary metal (As, Pb, Cd, and Mn) measurements were collected from mothers in the 2nd and 3rd trimesters. Child BMI z-scores were dichotomized to normal (between -2 and +0.99) and high (≥1.00). Covariate-adjusted weighted quantile sum (WQS) regression models were used to estimate and examine the combined effect of metal biomarkers (i.e., blood and urine) on TRD measures. Effect modification by the child's BMI was evaluated using 2-way interaction terms. Children with a high BMI and greater exposure to the metal mixture during prenatal development exhibited significant temporal processing deficits compared to children with a normal BMI. Notably, children with increased exposure to the metal mixture and higher BMI had a decrease in the percent of tasks completed (β = -10.13; 95 % CI: -19.84, -0.42), number of average holds (β = -2.15; 95 % CI: -3.88, -0.41), longer latency (β = 0.78; 95 % CI: 0.13, 1.44), and greater variability in the standard deviation of the total hold time (β = 2.08; 95 % CI: 0.34, 3.82) compared to normal BMI children. These findings implicate that high BMI may amplify the effect of metals on children's temporal processing. Understanding the relationship between metal exposures, temporal processing, and childhood obesity can provide valuable insights for developing targeted environmental interventions.

Association between prenatal exposure to rare earth elements and the neurodevelopment of children at 24-months of age: A prospective cohort study

The increasing consumption of rare earth elements (REEs) has resulted in a considerable risk of environmental exposure. However, the adverse effects of prenatal REEs exposure on children's neurodevelopment are not yet fully recognized. Therefore, we investigated the individual and joint effects of prenatal exposure to 13 REEs on children's neurocognitive development based on 809 mother-child pairs from a large birth cohort in Wuhan, China. Maternal urinary concentrations of 13 REEs were repeatedly measured by inductively coupled plasma mass spectrometry. Children's neurodevelopment [e.g., mental and psychomotor development index (MDI/PDI)] at 24-months was assessed using Bayley Scales of Infant Development of Chinese Revision. GEE and BKMR models were applied to estimate the individual and joint effects of prenatal REE exposure on child neurodevelopment level. After controlling for typical confounders, we observed that exposure to 9 REEs during the first trimester were significantly associated with decreased MDI scores [βs and 95% confidence intervals (CIs) ranging from -2.24 (-3.86 ∼ -0.63) to -1.44 (-2.26∼ -0.26)], and 7 REEs during third trimester were significantly associated decreased PDI scores [β and 95% CIs ranging from -1.95 (-3.19 ∼ -0.71) to -1.25 (-2.34 ∼ -0.16)]. Higher quantiles of REE mixture in first and third trimester were associated with decreased MDI and PDI score. Thulium, erbium in the first trimester and cerium, lanthanum in the third trimester accounted most importance to joint effects on MDI and PDI, respectively. In conclusion, prenatal exposure to higher concentrations of REEs during the first and third trimester were negative associated with children's neurodevelopment.

Proteome signatures of joint toxicity to arsenic (As) and lead (Pb) in human brain organoids with optic vesicles

Arsenic (As) and lead (Pb) are toxins found in the natural surroundings, and the harmful health outcomes caused by the co-exposure of such toxins have become a considerable problem. However, the joint neurotoxicity of As and Pb to neurodevelopment and the underlying mechanisms remain unclear. Pluripotent stem cell-derived human brain organoids are emerging animal model alternatives for understanding neurological-related diseases. Therefore, we utilized brain organoids with optic vesicles (OVB-organoids) to systematically analyze the neurotoxicity of As and Pb. After 24 h of As and/or Pb exposure, hematoxylin-eosin staining revealed that As and Pb exposure could cause disorders in the structure of the ventricular zone and general cell disarrangement in OVB-organoids. Immunostaining displayed that OVB-organoids are more susceptible to As and Pb co-exposure than independent exposure in apoptosis, proliferation, and cell differentiation. Meanwhile, even though As and Pb could both hinder cell proliferation, contrary to Pb, As could induce an increasing proportion of mitotic (G2/M) cells. The proteome landscape of OVB-organoids illustrated that Pb synergized with As in G2/M arrest and the common role of As and Pb in carcinogenesis. Besides, proteomics analyses suggested the consequential role of autophagy and Wnt pathway in the neurotoxicity of As and Pb co-exposure. Overall, our findings provide penetrating insights into the cell cycle, carcinogenesis, autophagy, and Wnt pathway underlying the As and Pb binary exposure scenarios, which could enhance our understanding of the mixture neurotoxicity mechanisms.

Biomarkers and Tourette syndrome: a systematic review and meta-analysis

Objective

This research aims to investigate whether peripheral biomarkers might differentiate individuals with Tourette syndrome (TS) from those without the condition.

Methods

A broad range of databases was searched through November 2022. This study employed a systematic literature review and subsequent meta-analysis of case-control studies that assessed the aberration of biomarkers of patients with TS and controls.

Results

A total of 81 studies were identified, out of which 60 met the eligibility criteria for inclusion in the meta-analysis. Following a meticulous screening procedure to determine the feasibility of incorporating case-control studies into the meta-analysis, 13 comparisons were statistically significant [CD3+ T cell, CD4+ T cell, CD4+ T cell to CD8+ T cell ratio, NK-cell, anti-streptolysin O antibodies, anti-DNase antibodies, glutamic acid (Glu), aspartic acid (Asp), ferritin (Fe), zinc (Zn), lead (Pb), vitamin D, and brain-derived neurotrophic factor (BDNF)]. Publication bias was found for anti-streptolysin O antibodies. Suggestive associations were evidenced for norsalsolinol (NSAL), neuron-specific enolase (NSE), and S100B.

Conclusion

In this study, we present empirical evidence substantiating the link between several peripheral biomarkers and the early diagnosis of TS. Larger and more standardized studies are necessary to replicate the observed results, elucidate the specificity of the biomarkers for TS, and evaluate their precision for use in clinical settings.

Assessment and Bioaccumulation of Heavy Metals in Water, Fish (wild and Farmed) and Associated Human Health Risk

Worldwide, anthropogenic activities are causing the natural environment and aquaculture systems to become heavily contaminated with heavy metals, which can lead to consumer's health problems. In the current study, wild and farmed fish (n = 30) and water samples (n = 6) have been collected from the Chashma barrage and fish farm to assess the heavy metals concentration, i.e., Cu, Cd, Pb, Zn and Cr, in the water and some important organs (gills, liver, muscle, brain and bones) of wild and farmed fish (Labeo rohita) using Graphite furnace Atomic absorption spectrometry. Bioaccumulation factor and human health risk assessment were calculated to measure the health status of both fish and humans. Results show that in wild and farm fish's gills, muscles and bones, the trend of the heavy metals was Zn > Pb > Cu > Cd > Cr. On the other hand, the brain and liver show Zn > Cu > Pb > Cd > Cr trend. Comparatively, the heavy metals concentration was mostly higher (P < 0.05) in wild fish. Further; in both fish habitats (water) the heavy metals (Cd and Pb) concentration was higher than the WHO standard level, while in the body, Cd was higher (P < 0.05) in all studied organs except the muscle, Cr was only lower (P > 0.05) in muscle and brain. Pb was higher (P < 0.05) in all studied organs of both fish. Bioaccumulation of heavy metals was mostly higher (P < 0.05) in wild fish than in farmed. EDI and THQ were higher in wild fish, but the HI value was lower than 1 for both fish. Moreover, the PCA analysis suggests a positive correlation between heavy metals concentration in fish organs and the water of both fish (wild and farmed). Results indicated that farmed fish showed less potential risk to humans than wild fish.

Lead exposure induced transgenerational developmental neurotoxicity by altering genome methylation in Drosophila melanogaster

Heavy metal toxicity is a significant global health concern, with particular attention given to lead (Pb) exposure due to its adverse effects on cognitive development, especially in children exposed to low concentrations. While Pb neurotoxicity has been extensively studied, the analysis and molecular mechanisms underlying the transgenerational effects of Pb exposure-induced neurotoxicity remain poorly understood. In this study, we utilized Drosophila, a powerful developmental animal model, to investigate this phenomenon. Our findings demonstrated that Pb exposure during the developmental stage had a profound effect on the neurodevelopment of F0 fruit flies. Specifically, we observed a loss of correlation between the terminal motor area and muscle fiber area, along with an increased frequency of the β-lobe midline crossing phenotype in mushroom bodies. Western blot analysis indicated altered expression levels of synaptic vesicle proteins, with a decrease in Synapsin (SYN) and an increase in Bruchpilot (BRP) expression, suggesting changes in synaptic vesicle release sites. These findings were corroborated by electrophysiological data, showing an increase in the amplitude of evoked excitatory junctional potential (EJP) and an increase in the frequency of spontaneous excitatory junctional potential (mEJP) following Pb exposure. Importantly, our results further confirmed that the developmental neurotoxicity resulting from grandparental Pb exposure exhibited a transgenerational effect. The F3 offspring displayed neurodevelopmental defects, synaptic function abnormalities, and repetitive behavior despite lacking direct Pb exposure. Our MeDIP-seq analysis further revealed significant alterations in DNA methylation levels in several neurodevelopmental associated genes (eagle, happyhour, neuroglian, bazooka, and spinophilin) in the F3 offspring exposed to Pb. These findings suggest that DNA methylation modifications may underlie the inheritance of acquired phenotypic traits resulting from environmental Pb exposure.

Health risk assessment of heavy metals in exposed workers of municipal waste recycling facility in Iran

Exposure to heavy metals (HMs) present in the particulate matter from municipal solid waste during pretreatment and recycling processes may pose a serious health risk to workers. This was the first study on the exposure of municipal solid waste (MSW) recycling workers to toxic metals. The concentrations of HMs (Cd, Pb, As, Co, Cr, Ni, Cu, Fe, Mn, and Zn) during personal exposure to PM2.5 among municipal waste recycling facility workers in Kashan City, Iran, were investigated from January 15 to March 15, 2023. The research was performed in the three main stages of the waste recycling process: dismantling, sorting, and collecting. PM2.5 samples were collected using a personal environmental monitor (PEM) attached to a sampling pump. The non-carcinogenic and carcinogenic health risk values and related uncertainty for waste recyclers from HMs inhalational exposure were calculated using USEPA methodology and Monte Carlo simulations. The results showed that the dismantlers exhibited the highest exposure concentrations of PM2.5 (mean 2148 ± 1257 μg m-3), followed by sorters (mean 1864 ± 965 μg m-3), and collectors (mean 1782 ± 876 μg m-3). Health risk assessment indicated that 95th percentile contents of Ni, As, Co, and Zn were responsible for the non-carcinogenic risk (HQ) values exceeding the acceptable level of 1. The contents of As, Ni, and Cr in PM2.5 caused a non-acceptable carcinogenic risk for waste recyclers due to inhalational exposure, as the carcinogenic risk (CR) values exceeded the acceptable threshold of 1 × 10-6. Monte Carlo simulation results revealed that the mean and median CR values from inhalational exposure to carcinogenic HMs exceeded the acceptable level of 1 × 10-6 for municipal waste recyclers. As results of this study indicated the high-risk to hazardous metals for waste recyclers due to occupational exposure in the MSW recycling sites, it is suggested to consider workers' exposure as the public health concern.

Beyond the outdoors: indoor air quality guidelines and standards - challenges, inequalities, and the path forward

In the last few decades, indoor air quality (IAQ) has become a major threat to public health. It is the fifth leading cause of premature death globally. It has been estimated that people spend ∼90 % of their time in an indoor environment. Consequently, IAQ has significant health effects. Although IAQ-related standards and guidelines, policies, and monitoring plans have been developed in a few countries, there remain several global inequalities and challenges. This review paper aims to comprehensively synthesize the current status of widely accepted IAQ guidelines and standards. It analyzes their global implementation and effectiveness to offer insights into challenges and disparities in IAQ policies and practices. However, the complexity of domestic environments and the diversity of international standards impede effective implementation. This manuscript evaluates international, national, and regional IAQ guidelines, emphasizing similarities and differences. In addition, it highlights knowledge gaps and challenges, urging the international scientific community, policymakers, and stakeholders to collaborate to advance IAQ standards and guidelines. The analysis evaluates the efficacy of guidelines, identifies deficiencies, and offers recommendations for the future of domestic air quality standards.

Remediation of lead-contaminated groundwater by oyster shell powder-peanut shell biochar mixture

Groundwater pollution caused by lead ions has become a widespread issue worldwide due to the ever-increasing development of industrial activities. Such pollution poses significant threats to both humans and the environment. Oyster shell powder-peanut shell biochar mixture (OSP-PSB mixture) was used for lead-contaminated groundwater treatment by permeable reactive barrier (PRB) technology. Basic characteristics of materials proved that OSP-PSB mixture has good adsorption properties; OSP with particle sizes ranging from 0.85 to 1.18 mm was used in this research; according to engineering and adsorption characteristics, OSP-PSB mixture (5:1) showed excellent permeability (4.35 × 10-4 cm/s) and lead adsorption capacity(27 mg/g); long-term permeability of the OSP-PSB mixture slightly decreased over time and met the permeability requirements for PRB; the removal mechanisms of lead ions by OSP-PSB mixture include precipitation, surface complexation, ion exchange, and physical adsorption. The experiment results showed that the OSP-PSB mixture fulfills the actual project requirements of PRB.

A new mechanistic insight into the association between environmental perfluorooctane sulfonic acid (PFOS) exposure and attention deficit and hyperactivity disorder (ADHD)-like behavior

Perfluorooctane sulfonic acid (PFOS) is one of the main residual environmental pollutants that threaten human health. PFOS exposure is positively correlated with the prevalence of attention deficit hyperactivity disorder (ADHD); however, the underlying mechanism is unknown. Given that dopamine (DA) is a crucial target for PFOS and that its dysfunction is a key role in ADHD development, it is speculated that PFOS exposure contributes to the occurrence of ADHD to some extent by disrupting DA homeostasis. To establish the relationship between PFOS exposure, DA dysfunction, and ADHD-like behavior, adult zebrafish were exposed to PFOS for 21 days using PFOS concentrations in the serum of patients with ADHD as the reference exposure dose. Results showed that PFOS caused ADHD-like behaviors, with the presence of the slightly elevated percentage of time spent in movement and prolonged time spent in reaching the target zone in the T-maze. Hyperactivity and cognitive ability impairment were more severe with increasing PFOS concentrations. Further investigation showed that PFOS exposure resulted in a decrease in the DA content, accompanied by a decrease in the number of dopaminergic neurons and a disturbance in the transcription profiles of genes associated with the dopaminergic system. Treatment with Ritalin effectively alleviated PFOS-induced ADHD-like behavior and restored DA levels, number of dopaminergic neurons, and expression of DA metabolism-related genes, suggesting that PFOS exposure induced ADHD-like behavior by triggering DA secretion disorder. This study enriches our understanding of the pathogenic mechanisms underlying ADHD development and emphasizes the importance of focusing on the health risks pertaining to environmental exposure.

Multiple exposures to heavy metals and changes in steroid hormones production in 4-year-old children

BACKGROUND

Prenatal exposure to multiple heavy metals can interfere with early neurodevelopment, lead to changes in sex hormone concentrations in children, and affect female reproductive health. To date, the influence of prenatal exposure to heavy metals on the endocrine system of children in Chinese electronic waste (e-waste) recycling areas has not been elucidated.

METHODS

Four weeks after delivery, 10 mL of human milk was collected for analysis of three heavy metals (lead (Pb), cadmium (Cd), and mercury (Hg)) via inductively coupled plasma mass spectrometry (ICP-MS). Four serum steroid hormones, including progesterone, testosterone, androstenedione (A-dione), and dehydroepiandrosterone (DHEA), were analyzed in 4-year-old children (25 boys and 17 girls). A multiple linear regression (MLR) model was implemented to investigate the association between each individual metal and serum steroid hormone. The exposure-response relationships were explored by generalized additive models (GAMs). Additionally, a Bayesian kernel machine regression (BKMR) model was used to assess the effects of multiple heavy metal exposures on each steroid hormone.

RESULTS

The MLR results show a significant positive association between a natural log unit increase in Hg and DHEA levels after adjusting for confounders (β = 65.50, 95% confidence interval (CI) = 4.37, 126.62). According to the GAM, the univariate exposure-response relationship of Hg on DHEA was almost linear. However, this association was attenuated based on the multiple metal MLR and BKMR results after accounting for multiple heavy metal exposures.

SIGNIFICANCE

Prenatal Hg exposure may affect sex hormones in children by affecting DHEA levels.

IMPACT STATEMENT

Prenatal maternal exposure to Hg may have long-term effects on the next generation. Hence, regulatory measures to reduce Hg exposure and long-term monitoring of children's health in e-waste areas are needed.

Pb inhibited C2C12 myoblast differentiation by regulating HDAC2

Myogenesis is a crucial process governing skeletal muscle development and homeostasis. Lead (Pb) exposure impaired the development and the health of bones, which slows the growth of children. However, it is far from clear what exactly the effects of Pb on skeletal muscle development are. In this study, C2C12 cells are commonly used as an in vitro model of muscle regeneration due to their ability to transition from a proliferative phase into differentiated myofibers. The dose of 1, 5, and 10 μM Pb were adopted to study the toxicity of Pb on C2C12 proliferation and differentiation. First, the effects of Pb on cell viability were detected and the results demonstrated that 5 μM and 10 μM Pb exposure decreased cell viability, while 1 μM Pb exposure has no obvious effects on cell viability. Then, 1-10 μM Pb exposure seriously reduced the C2C12 myoblasts differentiation, with the decrease of myogenic differentiation marker genes expression, including Muscle creatine kinase (MCK), Myosin Heavy Chain 4 (MYH4), Myogenin (MYOG), Myogenic Differentiation (MYOD). What's more, it was found that the epigenetic modifier histone deacetylase-2 (HDAC2) was upregulated after Pb exposure on C2C12 myoblasts. Further studies conclusively showed knockdown of HDAC2 ameliorated Pb-damaged C2C12 myoblasts differentiation, indicating HDAC2 plays a vital role in the Pb-induced C2C12 myoblasts differentiation deficits. In summary, these results demonstrated that Pb exposure inhibited C2C12 myoblasts differentiation by regulating HDAC2.

Cohort profile update: The Canadian Maternal-Infant Research on Environmental Chemicals Child Development study (MIREC-CD PLUS)

BACKGROUND

The pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study was established to determine whether maternal environmental chemical exposures were associated with adverse pregnancy outcomes in 2001 pregnant women.

OBJECTIVES

The MIREC-Child Development (CD PLUS) study followed this cohort with the goal of assessing the potential effects of prenatal exposures on anthropometry and neurodevelopment in early childhood.

POPULATION

MIREC families with children between the ages of 15 months and 5 years who had agreed to be contacted for future research (n = 1459) were invited to participate in MIREC-CD PLUS which combines data collected from an online Maternal Self-Administered Questionnaire with biomonitoring and neurodevelopment data collected from two in-person visits.

PRELIMINARY RESULTS

Between April 2013 and March 2015, 803 children participated in the Biomonitoring visit where we collected anthropometric measures, blood, and urine from the children. The Behavioural Assessment System for Children-2, Behaviour Rating Inventory of Executive Function, MacArthur-Bates Communicative Development Inventories and the Communication subscale of the Adaptive Behaviour Scale from the Bayley Scales of Infant and Toddler Development-III are available on close to 900 children. There were 610 singleton children who completed in-person visits for neurodevelopment assessments including the Social Responsiveness Scale, Wechsler Preschool Primary Scale of Intelligence-III and NEuroPSYchological assessments (NEPSY). Currently, we are following the cohort into early adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO).

CONCLUSIONS

Data collection for the MIREC-CD PLUS study is complete and analysis of the data continues. We are now extending the follow-up of the cohort into adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO). MIREC-CD PLUS is limited by loss to follow-up and the fact that mothers are predominately of higher socioeconomic status and 'White' ethnicity, which limits our generalizability. However, the depth of biomonitoring and clinical measures in MIREC provides a platform to examine associations of prenatal, infancy and childhood exposures with child growth and development.

Cognitive Performance and Exposure to Organophosphate Flame Retardants in Children: Evidence from a Cross-Sectional Analysis of Two European Mother-Child Cohorts

The knowledge of the effects of organophosphate flame retardants on children's neurodevelopment is limited. The purpose of the present research is to evaluate the association between exposure to organophosphate flame retardants and children's neurodevelopment in two European cohorts involved in the Human Biomonitoring Initiative Aligned Studies. The participants were school-aged children belonging to the Odense Child Cohort (Denmark) and the PCB cohort (Slovakia). In each cohort, the children's neurodevelopment was assessed through the Full-Scale Intelligence Quotient score of the Wechsler Intelligence Scale for Children, using two different editions. The children's urine samples, collected at one point in time, were analyzed for several metabolites of organophosphate flame retardants. The association between neurodevelopment and each organophosphate flame retardant metabolite was explored by applying separate multiple linear regressions based on the approach of MM-estimation in each cohort. In the Danish cohort, the mean ± standard deviation for the neurodevelopment score was 98 ± 12; the geometric mean (95% confidence interval (95% CI)) of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) standardized by creatinine (crt) was 0.52 µg/g crt (95% CI = 0.49; 0.60), while that of diphenyl phosphate (DPHP) standardized by crt was 1.44 µg/g crt (95% CI = 1.31; 1.58). The neurodevelopment score showed a small, negative, statistically imprecise trend with BDCIPP standardized by crt (β = -1.30; 95%CI = -2.72; 0.11; p-value = 0.07) and no clear association with DPHP standardized by crt (β = -0.98; 95%CI = -2.96; 0.99; p-value = 0.33). The neurodevelopment score showed a negative trend with BDCIPP (β = -1.42; 95% CI = -2.70; -0.06; p-value = 0.04) and no clear association with DPHP (β = -1.09; 95% CI = -2.87; 0.68; p-value = 0.23). In the Slovakian cohort, the mean ± standard deviation for the neurodevelopment score was 81 ± 15; the geometric mean of BDCIPP standardized by crt was 0.18 µg/g crt (95% CI = 0.16; 0.20), while that of DPHP standardized by crt was 2.24 µg/g crt (95% CI = 2.00; 3.52). The association of the neurodevelopment score with BDCIPP standardized by crt was -0.49 (95%CI = -1.85; 0.87; p-value = 0.48), and with DPHP standardized by crt it was -0.35 (95%CI = -1.90; 1.20; p-value = 0.66). No clear associations were observed between the neurodevelopment score and BDCIPP/DPHP concentrations that were not standardized by crt. No clear associations were observed with bis(1-chloro-2-propyl) phosphate (BCIPP) in either cohort, due to the low detection frequency of this compound. In conclusion, this study provides only limited evidence of an inverse association between neurodevelopment and exposure to BDCIPP and DPHP. The timing of exposure and effect modification of other organophosphate flame retardant metabolites and other substances should be the subject of further investigations that address this scientific hypothesis.

Chinese sapindaceous tree species (Sapindus mukorosii) exhibits lead tolerance and long-term phytoremediation potential for moderately contaminated soils

Heavy metal pollution in metropolitan soils poses significant risks to human health and the entire ecosystem. Effective mitigation strategies and technologies are crucial for addressing these environmental issues. Fast-growing trees are an essential part of phytoremediation projects all over the world and provide long-term ecological benefits to mankind. This study assessed the lead tolerance and phytoremediation potential of a fast-growing soapberry tree species (Sapindus mukorossi) in moderately contaminated soil. Two independent experiments were conducted to assess its tolerance at (i) germination level and (ii) prolonged growth stage. In the germination experiments, seeds were exposed to lead (II) nitrate Pb (NO₃)₂ at various concentrations (0, 5, 10, 20, 50, 100, 200, 300, 400 and 500 μM) for 120 days. Results showed significant differences in germination time, germination index, seedling vigor index, energy of germination, final germination, germination inhibition, seedling height and root/shoot weight compared to the control experiments. In the prolonged growth experiments, seedlings were grown for six months in soils amended/spiked with different Pb concentrations (T0 = 0, T1 = 20, T2 = 50, T3 = 100, T4 = 150 and T5 = 200 mg kg-1 soil) and their biomass was determined. The highest biomass achieved in six months (T0: 12.62 g plant-1), followed by (T1: 12.33 g plant-1), (T2: 12.42 g plant-1), (T3: 11.86 g plant-1), (T4: 10.86 g plant-1) and (T5: 10.06 g plant-1) respectively. S. mukorossi showed no visible signs of Pb toxicity over a six-month period. During six months of exposure, the total Pb content in S. mucrossi tissues were classified as roots > leaves > stems. The highest cumulative absorption of Pb occurred between the fourth and fifth months of exposure. Maximum transfer factor (TF) was detected during the fourth month ranging from 0.888 to 1.012 for the different Pb concentrations. Furthermore, the growth behavior, lead accumulation, bioconcentration factors (BCF) and tolerance index (TI) indicated that S. mucrossi may tolerate moderate Pb concentrations for longer periods. These findings suggest that S. mukorossi may be deployed for long-term phytoremediation coupled with urban forest applications in the future.

The Relationship between Blood Lead Level and Chronic Pain in US Adults: A Nationwide Cross-Sectional Study

INTRODUCTION

Lead toxicity has been a major public health problem worldwide, yet no study has investigated the association between lead exposure and chronic pain.

METHODS

We used data from three cycles of National Health and Nutrition Examination Survey (NHANES) with chronic pain status. We conducted univariate and multivariate logistic regression analyses to investigate the association between chronic pain and blood lead level (BLL). Subgroup analyses were performed to explore which confounding factor modified the association between chronic pain and BLL.

RESULTS

A total of 13,485 participants were included in our final analysis, out of which 1950 (14.46%) had chronic pain. In the fully adjusted model, a 1 μg/dL increase of BLL was associated with 3% higher risk of chronic pain. The highest BLL quartile (BLL > 2.40 μg/dL) was associated with a 32% increase in the risk of chronic pain compared with the lowest BLL quartile (BLL < 0.90 μg/dL). In the subgroup analyses, hypertension (P for interaction = 0.018) and arthritis (P for interaction = 0.004) status modified the association between BLL and chronic pain. Higher quartiles of BLL were associated with a higher risk of chronic pain only in individuals with hypertension or arthritis but not those without these conditions.

CONCLUSION

A higher BLL was associated with a higher risk of chronic pain. Further research is warranted to investigate whether a causal relationship exists between the two, as well as potential underlying mechanisms.

Lead, Cadmium, and Arsenic in Raw Cow's Milk in a Central Andean Area and Risks for the Peruvian Populations

Milk and its derivatives are basic foods in Peru, especially for children. The Junín region, in the central Andes, is one of the leading dairy basins. However, the safety of milk is affected by mining-metallurgical activities, wastewater dumping, organic residues, and inappropriate use of organophosphate fertilizers in agriculture whose contaminants reach the food chain, putting human health at risk. The purpose of this study was to evaluate the bioaccumulation of lead (Pb), cadmium (Cd), and arsenic (As) in milk produced on a representative farm in central Peru, which uses phosphorous agrochemicals and is adjacent to a small mineral concentrator and a municipal solid waste dump, and to evaluate the potential risk for the Peruvian population of 2-85 years considering three levels of daily intake by age, which constitutes the innovative contribution of the study. These three elements were quantified by flame atomic absorption spectrometry following standardized procedures. The mean contents of Pb (0.062 mg/kg), Cd (0.014 mg/kg), and As (0.030 mg/kg) in milk exceeded the maximum limits allowed by international standards. At all ages, the target quotient hazard followed a descending order of As > Pb > Cd, being > 1 in the case of As. The hazard index was >1 for children under 7, 9, and 11 years of age in the scenarios of low, medium, and high milk intake. The information is valid for formulating policies to prevent adverse health effects and develop standards and awareness programs, monitoring, and control of heavy metals in milk in Peru.

Toward an understanding of the role of the exposome on fragile X phenotypes

Fragile X syndrome (FXS) is the leading known monogenetic cause of autism with an estimated 21-50% of FXS individuals meeting autism diagnostic criteria. A critical gap in medical care for persons with autism is an understanding of how environmental exposures and gene-environment interactions affect disease outcomes. Our research indicates more severe neurological and metabolic outcomes (seizures, autism, increased body weight) in mouse and human models of autism spectrum disorders (ASD) as a function of diet. Thus, early-life exposure to chemicals in the diet could cause or exacerbate disease outcomes. Herein, we review the effects of potential dietary toxins, i.e., soy phytoestrogens, glyphosate, and polychlorinated biphenyls (PCB) in FXS and other autism models. The rationale is that potentially toxic chemicals in the diet, particularly infant formula, could contribute to the development and/or severity of ASD and that further study in this area has potential to improve ASD outcomes through dietary modification.

Environment and child well-being: A scoping review of reviews to guide policies

Background

Acting on social determinants is the most effective, efficient, and fairest strategy to improve population health and health equity. Because of their vulnerability and dependence, children are particularly exposed to the deleterious effects of their living environment. Taking these issues into account in the development of public policies and identifying levers for action are crucial. The objective of this scoping review of reviews is to identify the main environmental determinants on children's health and development, and their mechanisms of effect, to be addressed by public policies.

Methods

We conducted a scoping review of reviews in accordance with the method developed by Arksey and O'Malley, and Levac and colleagues' methodology advancement and the PRISMA guideline. Inclusion criteria were identified with the PICos (population-phenomena of interest-context-study design) framework. We used the PubMed database and conducted a thematic analyze.

Results

Forty-seven articles were selected. Their analysis allowed us to identify five categories of interdependent environmental determinants of child health: i) urban design ii) contaminants, iii) parenting environment, iv) social conditions, v) climate change. Together and in a systemic way, they act on the health of the child.

Conclusion

The review carried out allows us to propose a pragmatic framework for clarifying the effects of the physical, social, and economic environment on children's health and wellbeing.

Infant Saliva Microbiome Activity Modulates Nutritional Impacts on Neurodevelopment

Neurodevelopment is influenced by complex interactions between environmental factors, including social determinants of health (SDOH), nutrition, and even the microbiome. This longitudinal cohort study of 142 infants tested the hypothesis that microbial activity modulates the effects of nutrition on neurodevelopment. Salivary microbiome activity was measured at 6 months using RNA sequencing. Infant nutrition was assessed longitudinally with the Infant Feeding Practices survey. The primary outcome was presence/absence of neurodevelopmental delay (NDD) at 18 months on the Survey of Wellbeing in Young Children. A logistic regression model employing two microbial factors, one nutritional factor, and two SDOH accounted for 33.3% of the variance between neurodevelopmental groups (p < 0.001, AIC = 77.7). NDD was associated with Hispanic ethnicity (OR 18.1, 2.36-139.3; p = 0.003), no fish consumption (OR 10.6, 2.0-54.1; p = 0.003), and increased Candidatus Gracilibacteria activity (OR 1.43, 1.00-2.07; p = 0.007). Home built after 1977 (OR 0.02, 0.001-0.53; p = 0.004) and Chlorobi activity (OR 0.76, 0.62-0.93, p = 0.001) were associated with reduced risk of NDD. Microbial alpha diversity modulated the effect of fish consumption on NDD (X2 = 5.7, p = 0.017). These data suggest the benefits of fish consumption for neurodevelopment may be mediated by microbial diversity. Confirmation in a larger, randomized trial is required.

Early environmental exposure to oxytetracycline in Danio rerio may contribute to neurobehavioral abnormalities in adult zebrafish

The common antibiotic oxytetracycline (OTC) is nowadays commonly found in natural aquatic environments. However, the underlying mechanisms of low-dose OTC exposure and its neurotoxic effects on aquatic animals remain unknown. In this study, we exposed zebrafish larvae to environmental concentrations of OTC in early life and performed neurobehavioral, 16S rRNA gene sequencing, and transcriptomic analyses. OTC exposure resulted in hyperactivity of larvae and a significant reduction in the number of neurons in the midbrain. The expression levels of 15 genes related to neural function changed. Additionally, the composition of 65 genera of the gut microbiota of larvae was altered, which may be one of the reasons for the abnormal neural development. We further studied the long-term outcomes among adult fish long after cessation of OTC exposure. OTC treatment caused adult fish to be depressive and impulsive, symbolizing bipolar disorder. Adult fish exposed to OTC had significantly fewer neurons and their gut bacteria composition did not recover 104 days after terminating OTC exposure. Finally, we analyzed the correlation between the gut microbiota of larvae, genes related to neural function, and metabolites of adult fish brain tissue. The results showed that the abundance of several members of the biome in larvae was related to the transcription levels of genes related to neural function, which were related to the metabolic levels in the adult brain. In conclusion, our study showed that early-life exposure to environmental concentrations of OTC can lead to persistent neurobehavioral abnormalities until adulthood through dysbiosis in the gut microbiota.

Exposure of preterm neonates to toxic metals during their stay in the Neonatal Intensive Care Unit and its impact on neurodevelopment at 2 months of age

BACKGROUND

Premature neonates might be exposed to toxic metals during their stay in the neonatal intensive care unit (NICU), which could adversely affect neurodevelopment; however, limited evidence is available. The present study was therefore designed to assess the exposure to mercury, lead, cadmium, arsenic, and manganese of preterm neonates who received total parenteral nutrition (TPN) and/or red blood cell (RBC) transfusions during their NICU stay and the risk of neurodevelopment delay at the age of 2 months.

METHODS

We recruited 33 preterm neonates who required TPN during their NICU admission. Blood samples were collected for metal analysis at two different time points (admission and before discharge). Metals in the daily TPN received by preterm neonates were analyzed. Neurodevelopment was assessed using the Ages and Stages Questionnaire Edition 3 (ASQ-3).

RESULTS

All samples of TPN had metal contamination: 96% exceeded the critical arsenic limit (0.3 μg/kg body weight/day); daily manganese intake from TPN for preterm neonates exceeded the recommended dose (1 µg/kg body weight) as it was added intentionally to TPN solutions, raising potential safety concerns. All samples of RBC transfusions exceeded the estimated intravenous reference dose for lead (0.19 µg/kg body weight). Levels of mercury, lead and manganese in preterm neonates at discharge decreased 0.867 µg/L (95% CI, 0.76, 0.988), 0.831 (95%CI, 0.779, 0.886) and 0.847 µg/L (95% CI, 0.775, 0.926), respectively. A decrease in ASQ-3-problem solving scores was associated with higher levels of blood lead in preterm neonates taken at admission (ß = -0.405, 95%CI = -0.655, -0.014), and with plasma manganese (ß = -0.562, 95%CI = -0.995, -0.172). We also observed an association between decreased personal social domain scores with higher blood lead levels of preterm neonates before discharge (ß = -0.537, 95%CI = -0.905, -0.045).

CONCLUSION

Our findings provide evidence to suggest negative impacts on the neurodevelopment at 2 months of preterm infants exposed to certain metals, possibly related to TPN intake and/or blood transfusions received during their NICU stay. Preterm neonates may be exposed to levels of metals in utero.

Prenatal arsenic exposure, arsenic metabolism and neurocognitive development of 2-year-old children in low-arsenic areas

BACKGROUND

There is limited evidence on the effects of arsenic species and metabolic capacity on child neurodevelopment, particularly at low levels. Further, little is known about the critical window of exposure.

OBJECTIVE

To estimate the associations of arsenic exposure and arsenic metabolism in different pregnancy periods with neurodevelopment of two-year-old children.

METHODS

Concentrations of arsenobetaine (AsB), arsenite, arsenate, monomethyl arsenic acid (MMA), and dimethyl arsenic acid (DMA) in urine samples collected in three trimesters from 1006 mothers were measured using HPLC - ICPMS. Inorganic arsenic (iAs) was calculated as the sum of arsenite and arsenate. Total arsenic (tAs) was calculated as the sum of iAs, MMA and DMA. Child neurodevelopment was assessed with the Bayley Scales of Infant Development.

RESULTS

The geometric mean (GM) of SG-adjusted tAs in the first, second, third trimester was 16.37, 12.94, 13.04 μg/L, respectively. The mental development index (MDI) score was inversely associated with iAs and tAs. Compared to the 1st quartile, the MDI score decreased 0.43 (95%CI: -4.22, 3.36) for the 2nd, 6.50 (95%CI: -11.73, -1.27) for the 3rd, 5.42 (95%CI: -10.74, -0.10) for the 4th quartiles of iAs, and decreased 4.03 (95%CI: -7.90, -0.15) in the 4th quartile of tAs. In trimester-specific models, negative associations of DMA [-1.94 (95%CI: -3.18, -0.71)] and tAs [-1.61 (95%CI: -3.02, -0.20)] with the psychomotor development index (PDI) were only observed in 1st trimester.

CONCLUSIONS

Our study found inverse associations between prenatal arsenic exposure, especially in early pregnancy, and neurodevelopment of children at two years old, even at low exposure levels.

Prenatal Environmental Stressors and DNA Methylation Levels in Placenta and Peripheral Tissues of Mothers and Neonates Evaluated by Applying Artificial Neural Networks

Exposure to environmental stressors during pregnancy plays an important role in influencing subsequent susceptibility to certain chronic diseases through the modulation of epigenetic mechanisms, including DNA methylation. Our aim was to explore the connections between environmental exposures during gestation with DNA methylation of placental cells, maternal and neonatal buccal cells by applying artificial neural networks (ANNs). A total of 28 mother-infant pairs were enrolled. Data on gestational exposure to adverse environmental factors and on mother health status were collected through the administration of a questionnaire. DNA methylation analyses at both gene-specific and global level were analyzed in placentas, maternal and neonatal buccal cells. In the placenta, the concentrations of various metals and dioxins were also analyzed. Analysis of ANNs revealed that suboptimal birth weight is associated with placental H19 methylation, maternal stress during pregnancy with methylation levels of NR3C1 and BDNF in placentas and mother's buccal DNA, respectively, and exposure to air pollutants with maternal MGMT methylation. Associations were also observed between placental concentrations of lead, chromium, cadmium and mercury with methylation levels of OXTR in placentas, HSD11B2 in maternal buccal cells and placentas, MECP2 in neonatal buccal cells, and MTHFR in maternal buccal cells. Furthermore, dioxin concentrations were associated with placental RELN, neonatal HSD11B2 and maternal H19 gene methylation levels. Current results suggest that exposure of pregnant women to environmental stressors during pregnancy could induce aberrant methylation levels in genes linked to several pathways important for embryogenesis in both the placenta, potentially affecting foetal development, and in the peripheral tissues of mothers and infants, potentially providing peripheral biomarkers of environmental exposure.

Pyrethroid and Chlorpyrifos Pesticide Exposure, General Intellectual Abilities, and Executive Functions of School Children from Montevideo, Uruguay

Children's developing brains are susceptible to pesticides. Less is known about the effect of exposure to chlorpyrifos and pyrethroids on executive functions (EF). We measured urinary 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of chlorpyrifos, and urinary 3-phenoxybenzoic acid (3-PBA), a general, nonspecific metabolite of pyrethroids in first-grade children from Montevideo, Uruguay (n = 241, age 80.6 ± 6.4 months, 58.1% boys). EFs were assessed with the Intra-dimensional/Extra-dimensional shift (IED), Spatial Span (SSP), and Stockings of Cambridge (SOC) tests from the Cambridge Neuropsychological Test Automated (CANTAB) Battery. General intellectual ability (GIA) was assessed using the Woodcock-Muñoz Cognitive battery. Median (range) urinary TCPy and 3-PBA levels were 16.7 (1.9, 356.9) ng/mg of creatinine and 3.3 (0.3, 110.6) ng/mg of creatinine, respectively. In multivariable generalized linear models, urinary TCPy was inversely associated with postdimensional errors on the IED task β [95% CI]: -0.11 [-0.17, -0.06]. Urinary 3-PBA was inversely associated with the total number of trials -0.07 [-0.10, -0.04], and the total number of errors -0.12 [-0.18, -0.07] on the IED task. When TCPy and 3-PBA were modeled together, the associations did not differ from single-metabolite models. We found no evidence of effect modification by blood lead level (BLL). Pesticide exposure may affect EF performance in urban children.

The Effect of Smoking Habits on Blood Cadmium and Lead Levels in Residents Living Near a Mining and Smelting Area in Northwest China: a Cross-Sectional Study

Few studies have focused on environmental cadmium (Cd) and lead (Pb) exposure while exploring the effect of smoking on blood Cd (BCd) and blood Pb (BPb) levels. Moreover, essential trace elements affect the absorption, accumulation, and toxicity of Cd and Pb. To investigate the effect of smoking on BCd and BPb levels under high Cd and Pb exposure and the influence of essential trace elements on the effect, 301 residents living near a mining and smelting area in Northwest China were included in our study. After collecting health information and measuring BCd, BPb, serum iron, magnesium, and total calcium levels, we analyzed the association between smoking and BCd and BPb levels and the influence of the essential trace elements on the association. The results showed that BCd and BPb levels in smokers were significantly higher than those in non-smokers. There was a dose-response association between pack-years and the odds ratios (ORs) of high BCd and BPb levels in all participants compared with non-smokers. Serum iron, magnesium, and calcium had a negative effect on the elevations of the ORs of high BCd and BPb levels. In addition, smoking-related elevations of BCd and BPb levels vary by sex, age, BMI, and age of smoking initiation. Our findings present evidence for the effect of smoking on BCd and BPb levels under high Cd and Pb exposure and may provide guidance for the prevention and control of BCd and BPb elevations in residents living in Cd- and Pb-polluted areas.

Pb induces ferroptosis in choroid plexus epithelial cells via Fe metabolism

Pb can enhance blood-cerebrospinal fluid barrier (BCSFB) permeability and accumulate in brain tissue, leading to central nervous system (CNS) dysfunction. Choroid plexus (CP) epithelial cells are the main components of the BCSFB with crucial functions in BCSFB maintenance. However, the mechanism by which Pb exposure affects CP epithelial cells remains unclear. Here, ferroptosis was identified as the major programmed cell death modality by sophisticated high-throughput sequencing and biochemical investigations in primary cultured CP epithelial cells following Pb exposure. Bioinformatics analysis using the ferroptosis database revealed that 16 ferroptosis-related genes were differentially expressed in primary cultured CP epithelial cells following Pb exposure. Among them, Gpx4, Slc7a11, Tfrc, and Slc40a1 were hub ferroptosis-related genes. In addition, CP epithelial cells can be impaired when the concentration of the Pb²⁺ reached 2050 μg/L (10 μM PbAc), which included the decrease of cell viability, Gpx4 and Slc7a11 proteins expression, etc. Moreover, inhibition of ferroptosis enhanced CP epithelial cell viability and reduced BCSFB permeability in vitro following Pb exposure. In summary, ferroptosis of CP epithelial cells is involved in BCSFB dysfunction following Pb exposure. Gpx4, Slc7a11, Tfrc, and Slc40a1 are hub ferroptosis-related genes in CP epithelial cells.

Trends in elemental Pb concentrations within atmospheric PM2.5 and associated risk to human health in major cities of China

High concentrations of elemental lead (Pb) in the atmosphere pose a serious threat to human health. This study presents and summarizes data obtained from relevant literature on Pb concentrations within fine particulate matter (PM_2.5) recorded in major cities in China from 2008 to 2019. An environmental health risk assessment model was then used to evaluate the health hazards of inhaling Pb among adults and children in China. Owing to the promulgation and implementation of a series of air pollution control measures, the Pb concentrations within PM_2.5 measured in major cities in China showed a downward trend after peaking in 2013. The concentrations were higher in winter than in summer, and higher in northern cities than in southern cities. Although the Pb concentrations in most cities did not exceed the limit (500 ng/m³) set by China, they remained much higher than concentrations recorded in developed countries. The results of the environmental health risk analysis showed that the non-carcinogenic risk from atmospheric Pb exposure was higher in children than in adults (adult females > adult males), while the carcinogenic risk was higher in adults than in children. This study shows that even if the health risk of Pb in PM_2.5 does not exceed the acceptable limit, stricter Pb pollution control measures are required to safeguard population health due to the dangers of Pb.

Blood lead levels in children residing in a 115-year old urban settlement in Harare, Zimbabwe: a cross sectional study

BACKGROUND

Elemental lead (Pb) toxicity in children, irreversibly affects their growth and development. We assessed the prevalence of high blood Pb levels (BLL) in children living in a potentially high risk residential area and also assessed Pb levels in environmental specimens.

METHODS

This cross sectional study measured blood lead levels (BLL) in 86children living in Mbare, a densely populated suburb in Harare, Zimbabwe, characterised by dwellings progressively constructed from 1907 through to the 1940s, before the ban of leaded paint. Study participants of both genders were under 6 years of age. Potential risk factors of Pb poisoning were assessed. Pb levels were also assessed in soil, water and paint chip specimens from the study area.

RESULTS

The mean (standard deviation) BLL was 4.3 ± 0.75 g/dL. Twelve (13.95%) participants had BLL of > 5.0ug/dL. Our results showed no significant association between BLL and household income, participant behaviour/habits/activities, sources of drinking water, and the types of cookware used to prepare meals in their households.

CONCLUSION

Mean BLL observed in the current study were higher compared to those of children of similar age groups in the United States, suggesting that Pb contamination may be more ubiquitous in the Mbare flats area, potentially predisposing these children to impaired development.

Gestational lead exposure and its effects on fetal/infant development - A systematic review

Studies suggest that gestational exposure to lead (Pb) is related to spontaneous abortions, preterm birth, lower infant birth weight and length, and neurological dysfunctions. However, the evidence about its effects during pregnancy exposure on fetal and child development is still poor. Thus, the aim of this systematic review was to verify the association between prenatal exposure to Pb and the occurrence of neurobehavioral deficits, miscarriages, and child mortality. Observational studies with pregnant women exposed to Pb during pregnancy were included, without gender or ethnicity restrictions. The MEDLINE, Cochrane Library, EMBASE, Scopus, Web of Science, and LILACS databases were searched. The reading of titles and abstracts was conducted, followed by reading in full format and data extraction, that were performed independently by two reviewers. The included studies were evaluated by Downs and Black tool and qualitatively synthesized. Certainty of evidence was assessed by Grading of Recommendations Assessment, Development, and Evaluations (GRADE). The study protocol was registered with the Prospective Registry of Systematic Reviews (PROSPERO; CRD42022296750). Among twenty-one studies included, sixteen were classified as prospective cohort, two case-control, one nested case-control, one cohort, and one longitudinal study. No study that evaluated child mortality associated with gestational Pb exposure was found. There is a very low certainty of evidence in the association of gestational Pb exposure and neurobehavioral deficits or miscarriages. This systematic review reflects the poor evidence and the challenges of human toxicology studies, since it was not possible to associate gestational Pb exposure to neurobehavioral deficits, miscarriages, and child mortality.

Determinants of Exposure to Potentially Toxic Metals in Pregnant Women of the DSAN-12M Cohort in the Recôncavo Baiano, Brazil

Exposure to potentially toxic metals (PTM) threatens maternal and child health. We investigated the determinants of exposure to lead (Pb), cadmium (Cd), arsenic (As), and manganese (Mn) in 163 pregnant women from the Recôncavo Baiano, Brazil, enrolled in the DSAN-12M cohort. We measured these metals in biological samples (blood, toenails, and hair) and the Pb dust loading rates (RtPb) at their homes by graphite furnace atomic absorption spectrophotometry (GFAAS). Questionnaires were applied to collect sociodemographic and general habits data. Only 2.91% (n = 4) of the pregnant women had As levels above the detection limit. Few participants had levels above the recommended reference values for blood Pb (5.1; 95% CI: 2.1-10.1%), and Mn in hair or toenails (4.3; 95% CI: 2.3-10.1%). On the other hand, 61.1 (95% CI: 52.4-69.3%) had elevated blood Cd levels. After binary logistic regression, low socioeconomic status, domestic waste burning, being a passive smoker, multiparity, and renovating the house significantly increased the chances of having high levels of Mn, Pb, and Cd. We detected a worrying situation related to exposure to Cd, showing the urgency of implementing human biomonitoring in the general population, especially in situations of social vulnerability.

MiR-130/SNAP-25 axis regulate presynaptic alteration in anterior cingulate cortex involved in lead induced attention deficits

Brain volume decrease in the anterior cingulate cortex (ACC) after lead (Pb) exposure has been linked to persistent impairment of attention behavior. However, the precise structural change and molecular mechanism for the Pb-induced ACC alteration and its contribution to inattention have yet to be fully characterized. The present study determined the role of miRNA regulated synaptic structural and functional impairment in the ACC and its relationship to attention deficit disorder in Pb exposed mice. Results showed that Pb exposure induced presynaptic impairment and structural alterations in the ACC. Furthermore, we screened for critical miRNA targets responsible for the synaptic alteration. We found that miR-130, which regulates presynaptic vesicle releasing protein SNAP-25, was responsible for the presynaptic impairment in the ACC and attention deficits in mice. Blocking miR-130 function reversed the Pb-induced decrease in the expression of its presynaptic target SNAP-25, leading to the redistribution of presynaptic vesicles, as well as improved presynaptic function and attention in Pb exposed mice. We report, for the first time, that miR-130 regulating SNAP-25 mediates Pb-induced presynaptic structural and functional impairment in the ACC along with attention deficit disorder in mice.

Role of NF-κB in lead exposure-induced activation of astrocytes based on bioinformatics analysis of hippocampal proteomics

Lead (Pb), as a heavy metal, is used in batteries, ceramics, paint, pipes, certain ceramics, e-waste recycling, etc. Chronic Pb exposure can result in the inflammation of the central nervous system, as well as neurobehavioral changes. Both glial cells and neurons are involved in central nervous injury following Pb exposure. However, significant cellular events and their key regulators following Pb exposure remain to be elucidated. In this study, rats were randomly exposed to 250 or 500 mg/L PbAc for 9 weeks. Hippocampal proteomics was performed using isobaric tags for relative absolute quantification. Bioinformatics analysis was used to identify 301 and 267 differentially expressed proteins-which were involved in biological processes, including glial cell activation, neural nucleus development, and mRNA processing-in the low and high Pb exposure groups, respectively. Gene Set Enrichment Analysis showed that astrocyte activation was identified as a significant cellular event occurring in the low- or high-dose Pb exposure group. Subsequently, in vivo and in vitro models of Pb exposure were established to confirm astrocyte activation. As a result, glial fibrillary acidic protein expression in astrocytes was much higher in the Pb exposure group. Moreover, the mRNA expression of neurotoxic reactive astrocyte genes was much higher than that of the control group. The analysis of transcription factors indicated that NF-κB was screened as the top transcription factor, which might regulate astrocyte activation following Pb exposure in the rat hippocampus. The data also showed that the inhibition of NF-κB transcription suppressed astrocyte activation following Pb exposure. Overall, astrocyte activation was one of the significant cellular events following Pb exposure in the rat hippocampus, which was regulated by the NF-κB transcription factor, suggesting that inhibiting astrocyte activation may be a potential target for the prevention of Pb neurotoxicity.

Long term toxicities following developmental exposure to perfluorooctanoic acid: Roles of peroxisome proliferation activated receptor alpha

Perfluorooctanoic acid (PFOA) is a widespread persistent organic pollutant. Fertile chicken eggs were exposed to PFOA and incubated to hatch. At three time points post hatch (0-, 1- and 3-months old), chickens were subjected to electrocardiography and sacrificed. Serum was subjected to LC-MS/MS for PFOA concentration, and organs were subjected to histopathological assessments. Additionally, PPARα-silencing lentivirus was co-applied with PFOA exposure, and the corresponding phenotypes were evaluated. Western blotting was performed to assess expressions of FABPs and pSMAD2 in heart and liver samples. Considerable amount of PFOA were detected in hatchling chicken serum, but not in one-month-old or three-month-old chicken serum. PFOA exposure resulted in developmental cardiotoxicity and hepatotoxicity in hatchling chickens. Meanwhile, one-month-old chickens still exhibited elevated heart rate, but classical cardiac remodeling (thicker right ventricular wall) were observed in exposed animals. Three-month-old chickens exhibited similar results as one-month-old ones. PPARα silencing only had partial protective effects in hatchling chickens, but the protective effects seemed to increase as chickens aged. Western blotting results indicated that L-FABP was involved in PFOA-induced hepatotoxicity, while pSMAD2 was involved in PFOA-induced cardiotoxicity. In summary, developmental exposure to PFOA resulted in persistent cardiotoxicity, but not hepatotoxicity. PPARα participates in both cardiotoxicity and hepatotoxicity.

Effects of Pollution on Pregnancy and Infants

The fetus is particularly susceptible to environmental contaminants as it is developing at the time of pregnancy and is, therefore, more susceptible to their effects. Pregnancy loss, which includes stillbirth and spontaneous abortion (miscarriage), preterm labor and delivery, and neonatal death, is the worst pregnancy outcome. Stunting and its related health and developmental effects are particularly common in populations living in underdeveloped countries or those exposed to high levels of particle pollution. Several environmental toxins can affect an embryo, fetus, or infant as they are developing. This study explores the following questions: What part do pesticides, heavy metals, dioxin derivatives, and polychlorinated diphenyl compounds play as macroenvironmental pollutants in mutagenesis and teratogenesis? What effects do substances that exposed persons have considerable control over, such as alcohol, narcotics, and tobacco smoke, have on the microenvironment? What consequences should practitioners be aware of these toxins in terms of ethics and the law? This study seeks to assess pertinent primary scientific studies on how pollution affects the health of the fetus and newborn during pregnancy.

Sex-specific associations between cord blood lead and neurodevelopment in early life: The mother-child cohort (Shanghai, China)

The extent to which neurodevelopment is affected by prenatal lead exposure has not been conclusive. In addition, studies on the effects of sex on these relationships are inconsistent. The aim of this study was to investigate the impact of cord blood lead on neurodevelopment in children within sex subgroups. A total of 275 mother-child pairs from the Shanghai mother-child cohort were included. Umbilical cord blood lead was measured using graphite furnace atomic absorption spectrophotometry. The Bayley Scales for Infant Development-III (BSID-III) was used to measure the neurodevelopment of infants at the age of 18 ± 1.5 months. The median and interquartile range of cord blood lead levels in the total participants, male, and female children were 44.0 (24.5) μg/L, 44.0 (24.3) μg/L, and 46.0 (24.0) μg/L, respectively. According to multiple linear regression, cord blood lead concentrations showed a negative association with fine motor scores in all models associated with female children (β = -1.5; 95%confidence interval: -2.6, -0.4). However, prenatal lead levels were not associated with any of the BSID-III scores in male children. In addition, cord serum DHA was found positively related to fine motor scores in male children. Our findings suggest that prenatal lead exposure could lead to decreased motor function, although this phenomenon was only observed in female children. And DHA may be a protective factor against lead exposure in boys. Thus, further studies are needed to investigate the associations between prenatal lead exposure and neurobehavioral development, as well as the mechanism of sex differences.

Potentially Toxic Elements in Costume Cosmetics Used by Children and Adults Are Associated with Cancer Risk

(1) Background: Costume cosmetics, such as face paints and pancakes, are used by adults and children during Halloween, Carnival, or children's parties. However, the metallic-based pigments used as dyes in these products may contain toxic elements associated with different levels of exposure. Objectives: (a) to determine the Al, As, Ba, Cd, Co, Cr, Cu, Ni, Pb, Sb, Sn, and Sr concentrations in face paints and pancakes; and (b) to estimate cancer and non-cancer risks posed by the concentrations of each element in these products for dermal and ingestion exposure scenarios during children and adult use. (2) Methods: A total of 95 samples of face paints and pancakes (four brands in different textures and colors) were purchased at the largest high-street commercial center in São Paulo city, Brazil. An extraction procedure with nitric acid was carried out using a graphite-covered digester block. Toxic element determinations were performed using an ICP-MS. (3) Results: The non-cancer risks estimated were lower than 1, except for dermal exposure in adults for some target systems. High cancer risk values raise concerns in both groups. The risk for children ranged from 10^-8 to 10^-5 and proved higher in cases of accidental exposure by ingestion. For occupational exposure in adults, cancer risks were even higher, ranging from 10^-3 to 10^-5, with the highest values associated with dermal exposure. (4) Conclusions: The study results suggest the presence of potentially toxic elements (PTEs) in cosmetics should be regulated/monitored to protect human health, especially for occupational exposure and use by children.

Environmental Metal Exposure, Neurodevelopment, and the Role of Iron Status: a Review

PURPOSE OF REVIEW

Exposure to environmental metals, like lead (Pb), manganese (Mn), and methylmercury (Me-Hg), has consistently been implicated in neurodevelopmental dysfunction. Recent research has focused on identifying modifying factors of metal neurotoxicity in childhood, such as age, sex, and co-exposures. Iron (Fe) status is critical for normal cognitive development during childhood, and current mechanistic, animal, and human evidence suggests that Fe status may be a modifier or mediator of associations between environmental metals and neurodevelopment. The goals of this review are to describe the current state of the epidemiologic literature on the role of Fe status (i.e., hemoglobin, ferritin, blood Fe concentrations) and Fe supplementation in the relationship between metals and children's neurodevelopment, and to identify research gaps.

RECENT FINDINGS

We identified 30 studies in PubMed and EMBASE that assessed Fe status as a modifier, mediator, or co-exposure of associations of Pb, Me-Hg, Mn, copper (Cu), zinc (Zn), arsenic (As), or metal mixtures measured in early life (prenatal period through 8 years of age) with cognition in children. In experimental studies, co-supplementation of Fe and Zn was associated with better memory and cognition than supplementation with either metal alone. Several observational studies reported interactions between Fe status and Pb, Mn, Zn, or As in relation to developmental indices, memory, attention, and behavior, whereby adverse associations of metals with cognition were worse among Fe-deficient children compared to Fe-sufficient children. Only two studies quantified joint associations of complex metal mixtures that included Fe with neurodevelopment, though findings from these studies were not consistent. Findings support memory and attention as two possible cognitive domains that may be both vulnerable to Fe deficiency and a target of metals toxicity. Major gaps in the literature remain, including evaluating Fe status as a modifier or mediator of metal mixtures and cognition. Given that Fe deficiency is the most common nutritional deficiency worldwide, characterizing Fe status in studies of metals toxicity is important for informing public health interventions.

Melatonin alleviates lead-induced intestinal epithelial cell pyroptosis in the common carps (Cyprinus carpio) via miR-17-5p/TXNIP axis

Lead (Pb) has been concerned as one of the most severe hazardous contaminants, because it can cause pyroptosis in multiple tissues of mammals and birds. Melatonin (Mel) has attracted much interest for its role in governing intestinal injury via microRNAs (miRNAs). To explore the effect of Mel on Pb exposure-induced intestinal epithelial cell pyroptosis in common carps by regulating miR-17-5p/TXNIP axis, the Pb exposure and Pb-Mel treated models were constructed in vivo. The results elucidated that the suppressed expression of miR-17-5p and intensified level of TXNIP were primarily detected in Pb-exposed gut tissues, and both abolished with Mel addition, along with downregulated Pb-mediated elevated expression of NLRP3, CASP1, IL1β and GSDMD. Additionally, the targeting relationship between miR-17-5p and TXNIP were demonstrated by dual-luciferase reporter assay, and on this basis, miR-17-5p NC, mimic and inhibitor cell models were established. Thereby, Thereby, the expression of TXNIP in the miR-17-5p mimic groups was significant lower in the Pb-exposure but still elevated than the Control group, and the expression of NLRP3 and NLRP3-dependent pyrotposis-related genes performed consistent alterations. Noticeably, the expression of TXNIP suppressed with Mel addition even in the miR-17-5p inhibitor cell model, resulting in the inactivation of NLRP3 inflammasome-dependent pyroptosis. Overall, we draw the conclusion as Mel attenuates Pb-induced intestinal epithelial cell pyroptosis via miR-17-5p/TXNIP axis. The present study provides a novel perspective for toxicological mechanism of Pb, and new insights for the detoxification mechanism of Mel.

Determination of toxic metal burden and related risk factors in pregnant women: a biological monitoring in Sabzevar, Iran

Nowadays, the adverse effect of toxic metals on humans is well known, especially in the fetal period such as preventing cognitive development and congenital abnormalities of the central nervous system. Hence, this study aims to evaluate the toxic metal burden in mothers and newborns in Sabzevar. Obtained data can be useful for authorities in public health issues. To determine heavy metals in placental blood and umbilical cord blood, one hundred eighty blood samples were taken from ninety mothers referred to Shahidan Mobini Hospital for delivery. The amount of metals in samples was analyzed using inductively coupled plasma optical emission spectrometry (ICP OES). The results of this study revealed that 21.52%, 26.19%, and 60.71% of maternal blood samples (placental blood) and 16.47%, 56.47%, and 20% of umbilical cord blood samples were higher than the US center for disease control (CDC) recommended levels for Pb, Cd, and As respectively. According to the multiple linear regression analysis, the Pb (p = 0.054), As (p < 0.001), and Se (p < 0.001) levels had an association with the mother's living area. Also, there was a significant association between Se (0.021) and the age of the mother. However, the Se values in its optimum concentrations in the blood (60-140 μg/L) can decrease the adverse effects of toxic metals, 72.5% of the pregnant women had Se values below the 60 μg/L and only 6% of pregnant women had Se levels higher than 140 μg/L. We concluded that the mothers inhabiting the rural areas need more Se sources in their diets.

Lead exposure is non-linearly associated with subclinical myocardial injury in the general population without cardiovascular disease

Background and aims

Growing studies have focused on the effect of lead exposure on human circulatory system, while the relationship between lead exposure and subclinical myocardial injury (SC-MI) is still poorly known. Therefore, this study was to explore the effect of lead exposure on SC-MI.

Methods

The study included 6,272 individuals aged 40 and older without cardiovascular disease (CVD) from the third National Health and Nutrition Examination Survey. Blood lead was used as an alternative marker of lead exposure. Multivariable logistic regression models, restricted cubic spline and threshold effect analyses were performed to investigate the effect of blood lead on SC-MI.

Results

After adjusting for age, sex, race, diabetes, hypertension, systolic blood pressure, body mass index, waist-to-hip ratio, triglycerides, total cholesterol, creatinine, fasting plasma glucose and hemoglobin Alc, higher blood lead level was independently related to higher risk of SC-MI (OR 1.047, 95% CI [1.018, 1.077]; P = 0.003). Restricted cubic spline curve showed that there was a non-linear correlation between blood lead and SC-MI. Threshold effect analysis determined that the inflection point of blood lead was 3.8 ug/dl. When the blood lead level was higher than 3.8 ug/dl, there was an independent positive correlation between blood lead level and the risk of SC-MI (OR 1.031, 95% CI [1.009, 1.053]; P < 0.01). And similar associations were also observed among subgroups of male, ≤60 years, >60 years, never smoker, non-Hispanic White, non-Hispanic Black or without hypertension and diabetes.

Conclusions

Blood lead was non-linearly related to SC-MI in population free from CVD.