Very low lead exposures and children's neurodevelopment

Contribution of childhood lead exposure to psychopathology in the US population over the past 75 years

BACKGROUND

More than half of the current US population was exposed to adverse lead levels in childhood as a result of lead's past use in gasoline. The total contribution of childhood lead exposures to US-population mental health and personality has yet to be evaluated.

METHODS

We combined serial, cross-sectional blood-lead level (BLL) data from National Health and Nutrition Examination Surveys (NHANES) with historic leaded-gasoline data to estimate US childhood BLLs from 1940 to 2015 and calculate population mental-health symptom elevations from known lead-psychopathology associations. We utilized five outcomes: (1) General Psychopathology "points", reflecting an individual's liability to overall mental disorder, scaled to match IQ scores (M = 100, SD = 15); (2) Symptoms of Internalizing disorders (anxiety and depression) and Attention-deficit/Hyperactivity Disorder (AD/HD), both z-scored (M = 0, SD = 1); and (3) Differences in the personality traits of Neuroticism and Conscientiousness (M = 0, SD = 1).

RESULTS

Assuming that published lead-psychopathology associations are causal and not purely correlational: We estimate that by 2015, the US population had gained 602-million General Psychopathology factor points because of exposure arising from leaded gasoline, reflecting a 0.13-standard-deviation increase in overall liability to mental illness in the population and an estimated 151 million excess mental disorders attributable to lead exposure. Investigation of specific disorder-domain symptoms identified a 0.64-standard-deviation increase in population-level Internalizing symptoms and a 0.42-standard-deviation increase in AD/HD symptoms. Population-level Neuroticism increased by 0.14 standard deviations and Conscientiousness decreased by 0.20 standard deviations. Lead-associated mental health and personality differences were most pronounced for cohorts born from 1966 through 1986 (Generation X).

CONCLUSIONS

A significant burden of mental illness symptomatology and disadvantageous personality differences can be attributed to US children's exposure to lead over the past 75 years. Lead's potential contribution to psychiatry, medicine, and children's health may be larger than previously assumed.

Silent threats of lead-based paints in toys and households to children's health and development

Lead (Pb), a highly toxic heavy metal, poses a significant global health risk, particularly to children. Widely used in paint manufacturing for its remarkable corrosion-resistance properties Pb exposure has been linked to severe health issues, including reduced neurotransmitter levels, organ damage, potentially leading to death in extreme cases. Children Are particularly vulnerable, with Pb toxicity primarily affecting the brain, reproductive, kidneys, and cardiovascular systems. Approximately 0.6 million children worldwide suffer from cognitive impairments caused by Pb exposure. Despite varying Pb content regulations across countries, research has found that Pb concentration in paints often exceed permissible levels. A 0.01 mg/dL blood Pb level (BLL) is considered the threshold level as per the World Health Organization. However, recent studies reveal that significant health effects, including cognitive impairments in children, occur even at BLLs < 0.01 mg/dL. This review provides critical insights into the global production and use of Pb-based paints, release mechanisms of Pb, exposure pathways, and safety standards. It also highlights the harmful effects of Pb on human health, particularly in children, and its detailed toxicity mechanisms. Finally, this review identifies critical knowledge gaps and offers perspectives for future research.

Association of whole blood heavy metal concentrations with kidney function

Relatively elevated concentrations of arsenic, lead, and mercury are toxic to the kidneys. However, it is unknown whether kidney function is influenced by these metals in the general population without kidney diseases and without known exposure to these metals. We did a retrospective analysis of data collected from 58,864 outpatients in Germany from January 2014 to October 2022 undergoing measurements of arsenic, lead, and mercury. Routine clinical laboratory parameters were entered into the database if they were analyzed in the same patient within +/- four weeks of the metal analysis. The estimated glomerular filter rate (eGFR) was calculated using the 2021 CKD-EPI equation. The mean age of the study participants was 50.3 ± 17.1, of which 61.8% were women. Complete blood count, CRP, fasting glucose, liver and lipid values, and thyroid function parameters were within the normal range. Median (IQR) eGFR level was 92.14 (79.44-103.85) mL/min/1.73m2. Median (IQR) whole blood values for arsenic were 0.8 (0.4-1.5) µg/l, median (IQR) level for lead was 13.6 (9.5-19.5) µg/l, median (IQR) values for mercury were 0.8 (0.3-1.5) µg/l in whole blood. Arsenic (r= -0.131, p < 0.001, N = 11,211), lead (r = 0.318, p < 0.001, N = 21,733), and mercury (r= -0.149, p < 0.001, N = 22,670) levels correlate all inversely with eGFR. When plotting eGFR against whole blood metal concentrations, no lower safety thresholds were found. Multivariate analysis, considering age, sex, CRP, and fasting glucose as confounding factors, confirmed findings of independent associations of arsenic, lead, and mercury on eGFR. Subgroup analysis revealed that this inverse relationship was particularly pronounced in the lowest age tertile of all study participants. Concentrations of arsenic, lead, and mercury correlated independently inversely with eGFR in a German cohort that largely had a normal kidney function with no known exposure to heavy metals.

Association between some environmental risk factors and attention-deficit hyperactivity disorder among children in Egypt: a case-control study

BACKGROUND

Attention-Deficit Hyperactivity Disorder (ADHD) is a complex disease that negatively impacts the social and academic/occupational activities of children and is more common in boys than in girls.

METHODS

This case-control study aimed to assess the association between some environmental risk factors and ADHD among children in Alexandria, Egypt. It was carried out at the outpatient clinics of El Shatby Pediatric University Hospital in Alexandria, Egypt, with 252 children (126 cases and 126 controls). Hair samples were collected for analysis of lead and manganese levels using Atomic Absorption Spectrophotometer. A pre-designed interview questionnaire was used to determine the important environmental risk factors that may be related to ADHD.

RESULTS

Children from parents with low levels of education, living in crowded houses, and occupational exposure to chemical agents were found to be risk factors for ADHD. The mean ± SD hair lead level in ADHD children was 2.58 ± 1.95, while in controls was 1.87 ± 0.92, with a statistically significant difference (p < 0.001). The mean ± SD hair manganese level in ADHD children was 2.10 ± 1.54, while in controls was 1.11 ± 0.69, with a statistically significant difference (p < 0.001). The logistic regression model revealed that six factors had a significant association with ADHD: using of newspapers to wrap food 3 or more times a week (adjusted odds ratio (AOR) = 105.11, 95% CI: 11.18-988.26), daily TV watching by child for more than 5 h (AOR = 63.96, 95% CI: 2.56-1601.32), child's eating commercially packed noodles 3 times or more per week (AOR = 57.73, 95% CI: 3.77-593.93), using unpackaged flour in cooking (AOR = 44.47, 95% CI: 1.83-629.80), eating sweets daily by child (AOR = 6.82, 95% CI: 1.23-37.94), and lastly elevated hair Manganese level (AOR = 3.57, 95% CI: 1.24-10.29).

CONCLUSIONS

ADHD is a multi-factorial disorder, where many environmental risk factors contribute to its development. Future efforts to determine the best preventive strategy in Egypt must be based on a better knowledge of the role of environmental risk factors in the etiology of the disorder. Eliminating non-essential uses of lead and providing public education regarding the importance of safe disposal of lead-acid batteries and computers are necessary.

Validation of Psychometric Tools for Assessing Fatigue, Mood, and Sleep Quality: Application in the PREVES-STOP Study

Background and Objectives: Environmental pollution in regions like the Sarno River Basin in southern Italy significantly affects physical and psychological health. This study aimed to validate three novel psychometric tools-REST, HEAL-BDLC, and PEACE-for assessing fatigue, mood disturbances, and sleep quality in environmentally exposed populations. While correlations with heavy metal exposure will be addressed in a separate manuscript, this study focuses solely on psychometric validation. Materials and Methods: The PREVES-STOP Initiative recruited 88 participants aged 30-65 years from the Sarno River Basin. Participants completed psychometric questionnaires tailored to measure fatigue (REST), symptoms of depression and anxiety (HEAL-BDLC), and sleep quality (PEACE). Internal consistency, construct validity, and reliability were analyzed using Cronbach's alpha, correlation analyses, and principal component analysis (PCA). A subgroup received a nutraceutical intervention for us to explore their responsiveness to change over a two-week period. Results: REST (α = 0.969), HEAL-BDLC (α = 0.962), and PEACE (α = 0.736) demonstrated strong reliability. PCA confirmed the unidimensional structure of REST and the two-component structure of HEAL-BDLC (depression and anxiety dimensions) and PEACE (insomnia and sleep quality). Correlations with established measures, such as the WHO Well-Being Index, supported construct validity. Among the intervention participants, significant improvements were observed in fatigue (-12.5 REST median score), mood (-13.0 HEAL-BDLC median score), sleep (+1.5 PEACE median score), and overall well-being (+4.0 WHO-5 median score). Conclusions: REST, HEAL-BDLC, and PEACE are reliable and valid instruments for assessing nuanced health outcomes in environmentally exposed populations. They hold potential for guiding public health interventions and evaluating environmental remediation impacts. These findings lay the groundwork for future studies linking psychometric outcomes with heavy metal exposure.

Pan-European atmospheric lead pollution, enhanced blood lead levels, and cognitive decline from Roman-era mining and smelting

Ancient texts and archaeological evidence indicate substantial lead exposure during antiquity that potentially impacted human health. Although lead exposure routes were many and included the use of glazed tablewares, paints, cosmetics, and even intentional ingestion, the most significant for the nonelite, rural majority of the population may have been through background air pollution from mining and smelting of silver and lead ores that underpinned the Roman economy. Here, we determined potential health effects of this air pollution using Arctic ice core measurements of Roman-era lead pollution, atmospheric modeling, and modern epidemiology-based relationships between air concentrations, blood lead levels (BLLs), and cognitive decline. Findings suggest air lead concentrations exceeded 150 ng/m3 near metallurgical emission sources, with average enhancements of >1.0 ng/m3 over Europe during the Pax Romana apogee of the Roman Empire. The result was blood lead enhancements in young children of about 2.4 µg/dl above an estimated Neolithic background of 1.0 µg/dl, leading to widespread cognitive decline including a 2.5-to-3 point reduction in intelligence quotient throughout the Roman Empire.

Ambient Toxic Air Contaminants in the Maternal Residential Area during Pregnancy and Cerebral Palsy in the Offspring

BACKGROUND

Cerebral palsy (CP) is the most common permanent neuromotor disorder diagnosed in childhood. Although most cases have unknown etiology, emerging evidence suggests environmental risk factors of CP.

OBJECTIVES

We investigated whether ambient toxic air contaminants (TACs) in the maternal residential area during pregnancy, specifically volatile organic compounds (VOCs) and metals, were associated with offspring CP risk in California.

METHODS

We conducted a case-cohort study that included CP cases (N = 906 ) and a 20% random sample of all live singleton births (N = 184,954 ) who lived within a 5 -mile (8-km) radius of air toxics monitoring stations in California during 2005-2015 as the control comparison group. CP cases were ascertained from diagnostic records of the California Department of Developmental Services. We a priori selected TACs with suspected neurotoxicity and developmental toxicity, including 14 VOCs and 6 metals. We estimated the adjusted risk ratio (RR) and 95% confidence interval (CI) for CP and the average maternal residential exposures to each TAC over the entire pregnancy using modified Poisson regression. For air contaminant mixtures, we used quantile-based g-computation to estimate the effects of mixtures of VOCs or metals. Finally, we performed a negative control exposure analysis on exposure estimates of 36-48 months after delivery to evaluate uncontrolled confounding bias.

RESULTS

Maternal residential exposures to six VOCs (benzene, toluene, 1,3-butadiene, acetone, acetonitrile, and methylene chloride) and four metals (antimony, lead, nickel, and vanadium) were associated with 3%-25% higher risk of CP per interquartile range increase, and the estimated mixture effects of VOCs (RR = 1.24 ; 95% CI: 1.08, 1.43) or metals (RR = 1.38 ; 95% CI: 1.20, 1.58) were stronger. The observed associations were close to null for negative control exposures (36-48 months after delivery) to mixtures of VOCs or metals and CP.

DISCUSSION

In California, maternal prenatal residential exposure to VOCs and metals in the outdoor air, largely attributed to mobile traffic emission sources, was associated with an increased risk of CP in offspring. https://doi.org/10.1289/EHP14742.

Foreign Contaminants Target Brain Health

Neurodisease, caused by undesired substances, can lead to mental health conditions like depression, anxiety and neurocognitive problems like dementia. These substances can be referred to as contaminants that can cause damage, corruption, and infection or reduce brain functionality. Contaminants, whether conceptual or physical, have the ability to disrupt many processes. These observations motivate us to investigate contaminants and neurotoxicity collaboratively. This study investigates the link between pollutants and neuro-disease, examining transmission pathways and categorization. It also provides information on resources, causes, and challenges to minimize contamination risks. Contamination may cause various neuro-diseases, including Alzheimer's, Parkinson's, multi-system atrophy, Huntington's, autism spectrum disorder, psychiatric disorder, dementia, meningitis, encephalitis, schizophrenia, anxiety, and depression. The negative effects depend on the nature and extent of exposure. A comprehensive literature search was conducted using databases such as PubMed and Scopus, focusing on studies published till 2024. Studies were selected based on their examination of the relationship between environmental contaminants and brain health, emphasizing transmission pathways and the resulting neurological outcomes. Findings indicate that contaminants can penetrate the blood-brain barrier (BBB) via nasal, gut, and auditory routes, triggering harmful neurophysiological processes. This review highlights the urgent need for increased global awareness, policy interventions, and preventive measures to mitigate the long-term impacts of environmental contaminants on brain health, particularly in emerging nations.

Associations of gestational and childhood exposure to lead, cadmium, and fluoride with cognitive abilities, behavior, and social communication at 4 years of age: NICE birth cohort study

BACKGROUND

Early-life lead exposure affects cognitive development and emerging evidence suggests similar effects of cadmium and fluoride.

OBJECTIVE

To assess the impact of gestational and childhood exposure to lead, cadmium, and fluoride on cognitive abilities and behavioral and social communication problems.

METHODS

We studied 470 pregnant women (gestational week 29) and their 4-year-old children from the NICE cohort in northern Sweden. Concentrations of erythrocyte lead and cadmium and urinary cadmium were measured using inductively coupled plasma mass spectrometry and urinary fluoride with an ion-selective electrode. Urinary concentrations were specific-gravity adjusted. Associations of log2-transformed exposure concentrations with cognitive abilities (full-scale IQ and verbal comprehension by Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition), behavioral problems (Child Behavior Checklist), and social communication (Social Responsiveness Scale-Second Edition) were evaluated with multivariable-adjusted linear regression analysis.

RESULTS

Both gestational and cord erythrocyte lead concentrations were non-significantly inversely associated with child cognitive abilities (full-scale IQ: B [95%CI]: -1.2 [-2.9, 0.5] and -1.6 [-3.7, 0.4], respectively; per doubling of exposure). Similarly, both gestational and child urinary cadmium were inversely associated with cognitive abilities (full-scale IQ: -1.1 [-2.5, 0.3] and -1.1 [-2.5, 0.4], verbal comprehension: -1.2 [-3.1, 0.6] and -1.4 [-3.4, 0.6], respectively). Urinary fluoride concentrations showed no association with cognitive abilities. However, gestational fluoride was associated with increasing externalizing problems (0.9 [-0.3, 2.0]) and ADHD raw scores (0.3 [0.0, 0.6]). Childhood erythrocyte lead and urinary cadmium were non-significantly associated with increased behavioral problems (lead with total problems: 1.2 [-0.4, 2.9] and internalizing problems: 1.5 [-0.4, 3.4]; cadmium with externalizing problems: 1.1 [-0.2, 2.4]).

CONCLUSION

Despite non-significant associations, both lead and cadmium exposure showed consistent inverse associations with cognitive abilities at 4 years, whereas associations with behavioral problems were less conclusive, especially for cadmium. Results on fluoride indicated association with externalizing problems, including ADHD, but prevalence of behavioral problems was low, increasing uncertainty.

Epigenetic Mechanisms in Aging: Extrinsic Factors and Gut Microbiome

BACKGROUND/OBJECTIVES

Aging is a natural physiological process involving biological and genetic pathways. Growing evidence suggests that alterations in the epigenome during aging result in transcriptional changes, which play a significant role in the onset of age-related diseases, including cancer, cardiovascular disease, diabetes, and neurodegenerative disorders. For this reason, the epigenetic alterations in aging and age-related diseases have been reviewed, and the major extrinsic factors influencing these epigenetic alterations have been identified. In addition, the role of the gut microbiome and its metabolites as epigenetic modifiers has been addressed.

RESULTS

Long-term exposure to extrinsic factors such as air pollution, diet, drug use, environmental chemicals, microbial infections, physical activity, radiation, and stress provoke epigenetic changes in the host through several endocrine and immune pathways, potentially accelerating the aging process. Diverse studies have reported that the gut microbiome plays a critical role in regulating brain cell functions through DNA methylation and histone modifications. The interaction between genes and the gut microbiome serves as a source of adaptive variation, contributing to phenotypic plasticity. However, the molecular mechanisms and signaling pathways driving this process are still not fully understood.

CONCLUSIONS

Extrinsic factors are potential inducers of epigenetic alterations, which may have important implications for longevity. The gut microbiome serves as an epigenetic effector influencing host gene expression through histone and DNA modifications, while bidirectional interactions with the host and the underexplored roles of microbial metabolites and non-bacterial microorganisms such as fungi and viruses highlight the need for further research.

Multi-omics inhalation toxicity assessment of urban soil dusts contaminated by multiple legacy sources of lead (Pb)

Although animal studies have evaluated lead (Pb) toxicity, they are limited to soluble forms, such as Pb-acetate, which do not reflect the range found in the exposome. Recent studies on Pb speciation of residential soils in urban areas revealed that the initial Pb sources are not persistent and are extensively repartitioned into adsorbed forms of Pb rather than insoluble phosphates. We investigated the inhalation and neurological toxicity of dusts generated from a surficial soil sample collected from a residential site with an exposomic mixture of various Pb species, both adsorbed phases (Fe and Mn oxide, humate bound Pb) and mineral phases (Pb hydroxycarbonate, pyromorphite, galena). Mice inhaled East Chicago dust (ECD) generated from a composite soil sample for 4 h/day, 7 days/week, for 4 weeks. Mice were necropsied immediately, 1, 14 and 30 days post exposure to evaluate both toxicity and recovery. Exposure to ECD caused changes in memory and spatial learning in the Morris Water Maze test. RNAseq analysis of the hippocampus region revealed multiple differentially expressed genes and impacts on pathways involved in ion channel complexes, and neuron-to-neuron synapse. Metabolomics analysis of plasma highlighted significant alterations in metabolic processes immediately after exposure that resolved after 14 days of rest.

The relationship between lead levels and reading acquisition in Spanish speakers, evidence from Uruguayan schoolers

Lead is a well-known neurotoxicant that continues to affect children´s cognition and behavior. Nevertheless, we still have little evidence on the consequences of lead exposure on reading abilities, particularly in languages other than English.

OBJECTIVE

To investigate the cross-sectional association between blood lead levels (BLL), and pre-reading and reading abilities in first-grade children from Montevideo, Uruguay.

METHOD

Of 357 school children (age 67-105 months) enrolled into the study, 287(43 % girls) had a BLL measure and an assessment of pre-reading and reading abilities based on five tests (Verbal comprehension, Sound blending, Letter word identification, Sentence reading fluency, and Passage comprehension) from the Batería III Woodcock-Muñoz. Separate generalized linear models (GLM) were conducted on the relationship between BLL and each test score separately, adjusting for sex, maternal education, household assets, Home Observation for Measurement of the Environment Inventory score, season, test administrator, blood lead testing method, and school clusters.

RESULTS

The mean BLL was 4.0 ± 2.2 µg/dL, with no differences between the sexes. BLL was associated with a poorer vocabulary knowledge (β [95 % CI]): -0.20 [-0.39, 0.01]. For all the tests, children with BLLs ≥5 µg/dL tended to exhibit poorer performance than children with lower BLLs, but these associations were not statistically significant. When stratified by sex, some evidence of differential associations between BLLs and reading abilities emerged: BLLs were associated with higher phonological awareness in girls (0.32 [0.15, 0.48]) but not boys, and with lower reading comprehension in boys (-0.54 [-1.20, 0.13]) but not girls. Also, lead exposure (BLL ≥ 5 µg/dL) was more strongly and negatively associated with phonological awareness (-1.22 [-1.57, -0.86]) in boys than girls.

CONCLUSION

In this study of first-grade children learning to read in Spanish, we found an inverse association between lead exposure and vocabulary scores, as well as tendency toward lower performance on pre-reading and reading measures among children with BLLs ≥5 µg/dL. Pre-reading and reading abilities are relevant to literacy acquisition; further research is required to confirm these links in larger studies, and to investigate differences between boys and girls, and according to key sociodemographic characteristics.

Heavy Metals in Umbilical Cord Blood: Effects on Epigenetics and Child Development

Heavy metals like arsenic, mercury, cadmium, and lead are harmful pollutants that can change how our genes are regulated without altering the DNA sequence, specifically through a process called DNA methylation (DNAm) at 5-methylcytosine, an epigenetic mark that we will focus on in this review. These changes in DNAm are most sensitive during pregnancy, a critical time for development when these modifications can affect how traits are expressed. Historically, most research on these environmental effects has focused on adults, but now there is more emphasis on studying the impacts during early development and childhood. The placenta acts as a protective barrier between the mother and the baby, and by examining it, scientists can identify changes in key genes that might affect long-term health. This review looks at how exposure to heavy metals during pregnancy can cause changes in the gene regulation by DNAm in newborns, as seen in their umbilical cord blood. These changes reflect the baby's genetic state during pregnancy and can be influenced by the mother's environment and genetics, as well as the baby's own genetics.

The Challenges of Treating Lead Toxicity During the COVID-19 Pandemic

Despite decades of environmental reform, legacy lead is a persistent health hazard within communities. Secondary prevention with screening for childhood lead exposure typically occurs at the 12-month and 24-month well visits, and early identification of toxicity is of vital importance to reduce morbidity and mortality. Over the past few years, there have been multiple challenges impacting the management of lead toxicity, including the coronavirus disease 2019 pandemic, a national shortage of the chelation agent CaNa2EDTA, and housing-related concerns that may result in re-exposure of lead before lead abatement. This report identifies the importance of lead screening and limitations that a pandemic has placed on health care while emphasizing access to care and community resources needs to be a priority.

Association Between Ambient Air Pollution and Attention-Deficit/Hyperactivity Disorder (ADHD) in Children: A Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to assess the association between postnatal exposure to ambient air pollutants (particulate matter (PM)2.5, PM10, nitrogen dioxide (NO2)) and the risk of attention-deficit/hyperactivity disorder (ADHD) in children. Observational studies, including cohort, case-control, and cross-sectional designs, that examined the relationship between postnatal exposure to ambient air pollution and ADHD in children were included, while studies focusing on prenatal exposure or unrelated neurodevelopmental outcomes were excluded. A comprehensive search of databases including PubMed, Web of Science, Embase, and Ovid, last updated in May 2024, was conducted. The risk of bias in the selected studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools, with discrepancies resolved through discussion among four reviewers. A meta-analysis was performed, synthesizing results using hazard ratios (HR), odds ratios (OR), and risk ratios (RR) as effect sizes. Random effects models were applied in most analyses due to the expected variability between studies, while fixed effects models were employed where only two studies were available. A total of 25 studies were included, with sample sizes ranging from 174 to 35,103 children. The studies were conducted in different countries and varied in their design and pollutant exposure measurement methods. The meta-analysis demonstrated a significant association between PM2.5 exposure and ADHD, with moderate heterogeneity (I² = 74.2%). PM10 exposure was also significantly associated with ADHD, and the heterogeneity was reduced to 34.94% after excluding an influential outlier. NO2 exposure similarly showed a significant association with ADHD, with low heterogeneity (I² = 0%). Due to the limited number of studies per pollutant (ranging from two to six), publication bias was not assessed. Despite the significant findings, there were limitations, including moderate to high heterogeneity among studies and the small number of studies per pollutant, which restricted the ability to assess publication bias and impacted the robustness of the results. Differences in exposure measurement methods and study designs also contributed to variability in the findings. Nonetheless, the evidence suggests that postnatal exposure to ambient air pollutants, particularly PM2.5, PM10, and NO2, is significantly associated with an increased risk of ADHD in children. These results underscore the importance of conducting further large-scale, high-quality studies to explore these associations in greater depth and to elucidate the mechanisms underlying the link between air pollution and ADHD.

Do lead (Pb) content of lipsticks expose a health risk to children? A risk assessment study

BACKGROUND

Lead (Pb) content in lipsticks and potential life-long exposure of which might cause severe effects in consumers are an important concern for public. Thus, studies emphasize that lead exposure has no safe levels.

METHODS

From 10 different brands, in total, 25 solid, gloss and creamy lipsticks are deployed from Turkish markets that are also categorized in two different price ranges. In order to evaluate the blood Pb levels in children, the United States Environmental Protection Agency's 'Exposure Uptake Biokinetic Model' is utilized. To assess the health risk of chronic usage both for children and adults, oral daily systemic exposure levels are calculated with the worst-case scenario and are compared with Maximum Allowable Dose Level for lipsticks. For lifetime risk assessment, exposure is assumed to start by age 7, and four different exposure scenarios have been deployed.

RESULTS

The mean lead content of lipsticks shows significant statistical differences between the high- and low-priced lipstick groups. Daily level and total risk for lifetime Pb exposure from deployed lipsticks are below the acceptable risk levels but long-worn usage of products with routine monitoring of metal content is crucial for sensitive and unintended exposure groups.

Refined Cumulative Risk Assessment of Pb, Cd, and as in TCM Decoction Based on Bioavailability through In Vitro Digestion/MDCK Cells

In this study, the oral bioavailability of Pb, Cd, and As in three types of traditional Chinese medicines (TCMs) and TCM decoctions were investigated through in vitro PBET digestion/MDKC cell model. Furthermore, a novel cumulative risk assessment model associated with co-exposure of heavy metal(loid)s in TCM and TCM decoction based on bioavailability was developed using hazard index (HI) for rapid screening and target organ toxicity dose modification of the HI (TTD) method for precise assessment. The results revealed that the bioavailability of Pb, Cd, and As in three types of TCM and TCM decoction was 5.32-72.49% and 4.98-51.97%, respectively. After rapid screening of the co-exposure health risks of heavy metal(loid)s by the HI method, cumulative risk assessment results acquired by TTD method based on total metal contents in TCMs indicated that potential health risks associated with the co-exposure of Pb, Cd, and As in Pheretima aspergillum (E. Perrier) and Oldenlandia diffusa (Willd.) Roxb were of concern. However, considering both the factors of decoction and bioavailability, TTD-adjusted HI outcomes for TCMs in this study were <1, indicating acceptable health risks. Collectively, our innovation on cumulative risk assessment of TCM and TCM decoction provides a novel strategy with the main purpose of improving population health.

Cottage industry as a source of high exposure to lead: A biomonitoring study among people involved in manufacturing cookware from scrap metal

In low-income countries, a widespread but poorly studied type of cottage industry consists of melting scrap metal for making cookware. We assessed the exposure to lead (Pb) among artisanal workers, and their families, involved in manufacturing cookware from scrap metal. In a cross-sectional survey, we compared artisanal cookware manufacturing foundries with carpentry workshops (negative controls) and car battery repair workshops (positive controls), all located in residential areas, in Lubumbashi (DR Congo). We collected surface dust in the workspaces, and blood and urine samples among workers, as well as residents living in the cookware workshops. Trace elements were quantified in the samples by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In surface dust, median Pb concentrations were higher in cookware foundries (347 mg/kg) than in carpentries (234 mg/kg) but lower than in battery repair workshops (22,000 mg/kg). In workers making the cookware (n = 24), geometric mean (GM) Pb blood cencentration was 118 μg/L [interquartile range (IQR) 78.4-204], i.e. nearly twice as high as among carpenters [60.2 μg/L (44.4-84.7), n = 33], and half the concentration of battery repair workers [255 μg/L (197-362), n = 23]. Resident children from the cookware foundries, had higher urinary Pb [6.2 μg/g creatinine (2.3-19.3), n = 6] than adults [2.3 (2.2-2.5), n = 3]. Our investigation confirms the high Pb hazard linked to car battery repair and reveals a high exposure to Pb among artisanal cookware manufacturers and their families, especially children, in residential areas of a city in a low-income country.

Effectiveness of soil remediation intervention in abandoned used lead acid battery (ULAB) recycling sites to reduce lead exposure among the children

Lead (Pb) is a neurotoxin, and children are vulnerable due to their evolving physiology and high-risk behaviours. Soil remediation interventions have proven effective in reducing Pb exposure. The primary objective is to measure the effectiveness of soil remediation at abandoned used lead acid battery (ULAB) recycling sites, nearby household cleaning, and community awareness in reducing blood lead levels (BLLs) in children. Additionally, this study aims to examine associations of Pb exposure with hematological, cardiovascular, renal, immunological, and endocrinological parameters in children aged 0-12 years. This study employs a quasi-experimental design, with abandoned ULAB sites as intervention sites and two control sites in Bangladesh. The intervention includes soil remediation coupled with community education. Data will be collected prior to the intervention and at a 12-month follow-up, including a comprehensive Pb exposure survey and collect environmental, turmeric samples, and blood from the child. Pb concentrations in environmental samples and turmeric samples will be determined using XRF analyser. Child BLL will be measured using Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) and proposed biochemical parameters will be analysed using routine laboratory methods. This study could provide valuable insights for designing targeted interventions in similar settings and mitigating exposure to Pb.

Trust and subjective knowledge influence perceived risk of lead exposure

Lead exposure is a persistent environmental hazard that poses risks to human health. But motivating protective action is challenging with this low visibility hazard whose health effects are often subtle and chronic. Higher risk perception is generally associated with taking protective measures, so public health efforts prioritize risk messaging. Yet, little is known about perceptions of lead exposure risk among the U.S. public. Using cross-sectional data from a national survey of 1035 U.S. residents, we measured the role of trust in government management of lead and subjective knowledge about lead as predictors of perceived risk of lead exposure, controlling for demographic and environmental factors. We also assessed if subjective knowledge moderated the relationship between trust and perceived risk. Our results reveal positive relationships between trust in government management of lead, subjective knowledge about lead, and risk perception, which we attribute in part to the important role government agencies play in secondary prevention, or communicating the risks of environmental lead exposure. We also found that younger people and people living in a house built before lead paint regulations passed in 1978 perceived higher lead risks. Our findings suggest that general communication about lead risks should aim to increase people's subjective knowledge in a consistent and balanced way that improves trust in government messengers.

Gender-Specific Effects on the Cardiorespiratory System and Neurotoxicity of Intermittent and Permanent Low-Level Lead Exposures

Lead exposure is a significant health concern, ranking among the top 10 most harmful substances for humans. There are no safe levels of lead exposure, and it affects multiple body systems, especially the cardiovascular and neurological systems, leading to problems such as hypertension, heart disease, cognitive deficits, and developmental delays, particularly in children. Gender differences are a crucial factor, with women's reproductive systems being especially vulnerable, resulting in fertility issues, pregnancy complications, miscarriages, and premature births. The globalization of lead exposure presents new challenges in managing this issue. Therefore, understanding the gender-specific implications is essential for developing effective treatments and public health strategies to mitigate the impact of lead-related health problems. This study examined the effects of intermittent and permanent lead exposure on both male and female animals, assessing behaviours like anxiety, locomotor activity, and long-term memory, as well as molecular changes related to astrogliosis. Additionally, physiological and autonomic evaluations were performed, focusing on baro- and chemoreceptor reflexes. The study's findings revealed that permanent lead exposure has more severe health consequences, including hypertension, anxiety, and reactive astrogliosis, affecting both genders. However, males exhibit greater cognitive, behavioural, and respiratory changes, while females are more susceptible to chemoreflex hypersensitivity. In contrast, intermittent lead exposure leads to hypertension and reactive astrogliosis in both genders. Still, females are more vulnerable to cognitive impairment, increased respiratory frequency, and chemoreflex hypersensitivity, while males show more reactive astrocytes in the hippocampus. Overall, this research emphasizes the importance of not only investigating different types of lead exposure but also considering gender differences in toxicity when addressing this public health concern.

Mass-Spectrometry-Based Research of Cosmetic Ingredients

Cosmetic products are chemical substances or mixtures used on the skin, hair, nails, teeth, and the mucous membranes of the oral cavity, whose use is intended to clean, protect, correct body odor, perfume, keep in good condition, or change appearance. The analysis of cosmetic ingredients is often challenging because of their huge complexity and their adulteration. Among various analytical tools, mass spectrometry (MS) has been largely used for compound detection, ingredient screening, quality control, detection of product authenticity, and health risk evaluation. This work is focused on the MS applications in detecting and quantification of some common cosmetic ingredients, i.e., preservatives, dyes, heavy metals, allergens, and bioconjugates in various matrices (leave-on or rinse-off cosmetic products). As a global view, MS-based analysis of bioconjugates is a narrow field, and LC- and GC/GC×GC-MS are widely used for the investigation of preservatives, dyes, and fragrances, while inductively coupled plasma (ICP)-MS is ideal for comprehensive analysis of heavy metals. Ambient ionization approaches and advanced separation methods (i.e., convergence chromatography (UPC2)) coupled to MS have been proven to be an excellent choice for the analysis of scented allergens. At the same time, the current paper explores the challenges of MS-based analysis for cosmetic safety studies.

Adherence to the national guidance on foods and drinks to limit or avoid during pregnancy in England: the PEAR Study

OBJECTIVE

The National Health Service (NHS) England website provides guidance on foods/drinks to avoid or limit during pregnancy because of microbiological, toxicological or teratogenic hazards. The aims were to determine adherence and whether demographic characteristics were associated with adherence.

DESIGN

Cross-sectional study.

SETTING

Online survey of postpartum women resident in England during pregnancy.

PARTICIPANTS

Recently, postpartum women resident in England during their pregnancy (n 598; median age 33 (IQR 30-36) years) completed an online questionnaire (April-November 2022). Questions included those on consumption of twenty-one food/drink items that the NHS advises pregnant women to avoid/limit. The study is part of the Pregnancy, the Environment And nutRition (PEAR) Study. Summary statistics were used to determine proportions adhering to the guidance. Adjusted logistic regression was used to model the associations of adherence with demographic characteristics.

RESULTS

Adherence was generally high (>90 % for eight of ten food/drink items to be avoided). However, among pre-pregnancy consumers, several items were not completely avoided, for example, 81 % (128/158) for game meat/gamebirds, 37 % (176/478) for cured meats and 17 % (81/467) for soft cheeses. Greater educational attainment (e.g. caffeinated soft drinks OR 2·25 (95 % CI 1·28, 3·94)), greater maternal age (e.g. oily fish 1·64 (1·05, 2·56)) and lower parity (e.g. caffeinated coffee 0.28 (0.11, 0.69)) were the most usual characteristics associated with adherence.

CONCLUSION

Evidence of concerning levels of non-adherence for some food/drink items suggests a case for more education on some of the guidance, particularly for women with lower educational attainment, greater parity and greater maternal age. Further research on barriers to the implementation of the guidance is needed.

Firearm-Related Lead Exposure and Child Lead Levels in the United States, 2012-2018

OBJECTIVE

To determine if firearm ownership is positively related to elevated child lead levels at a state-level, even when accounting for other sources of lead.

STUDY DESIGN

For this cross-sectional ecological study, we investigated whether household firearm ownership rates (a proxy for firearm-related lead exposure) was associated with the prevalence of elevated child blood lead levels in 44 US States between 2012 and 2018. To account for potential confounding, we adjusted for other known lead exposures, poverty rate, population density, race, and calendar year. To address missing data, we used multiple imputation by chained equations.

RESULTS

Prevalence of elevated child blood lead positively correlated with household firearm ownership and established predictors of lead exposure. In fully adjusted negative binomial regression models, child blood lead was positively associated with household firearm ownership and older housing; each IQR (14%) increase in household firearm ownership rate was associated with a 41% higher prevalence of childhood elevated blood lead (prevalence ratio: 1.41, 95% CI: 1.11-1.79).

CONCLUSION

These data provide state-level evidence that firearms may be an important source of child lead exposure. More research is needed to substantiate this relationship and identify modifiable pathways of exposure at the individual level.

Who tests for lead and why? A 10-year analysis of blood lead screening, follow-up and CNS outcomes in a statewide US healthcare system

OBJECTIVES

This study aims to determine (1) which providers in US healthcare systems order lead tests, why and at what frequency and (2) whether current patient population lead levels are predictive of clinical outcomes.

METHODS

Retrospective medical record study of all blood lead tests in the Medical University of South Carolina healthcare system 2012-2016 and consequent evidence of central nervous system (CNS)-related disease across a potential 10-year window (2012-2022).

RESULTS

Across 4 years, 9726 lead tests resulted for 7181 patients (49.0% female; 0-94 years), representing 0.2% of the hospital population. Most tests were for young (76.6%≤age 3) and non-Hispanic black (47.2%) and Hispanic (26.7%) patients. A wide variety of providers ordered tests; however, most were ordered by paediatrics, psychiatry, internal medicine and neurology. Lead levels ranged from ≤2.0 µg/dL (80.8%) to ≥10 µg/dL (0.8%; max 36 µg/dL). 201 children (3.1%) had initial lead levels over the reference value for case management at the time (5.0 µg/dL). Many high level children did not receive follow-up testing in the system (36.3%) and those that did often failed to see levels fall below 5.0 µg/dL (80.1%). Non-Hispanic black and Hispanic patients were more likely to see lead levels stay high or go up over time. Over follow-up, children with high lead levels were more likely to receive new attention-deficit/hyperactivity disorder and conduct disorder diagnoses and new psychiatric medications. No significant associations were found between lead test results and new CNS diagnoses or medications among adults.

CONCLUSIONS

Hospital lead testing covers a small portion of patients but includes a wide range of ages, presentations and provider specialities. Lack of lead decline among many paediatric patients suggests there is room to improve provider guidance around when to test and follow-up.

Integral trends in research of lead exposure and child health from 2012 to 2022: a bibliometric analysis

Lead poisoning in children is a non-negligible and ongoing threat to children's health and optimal development worldwide. There is no sufficient scientometric analysis available on this subject, though. Aiming to uncover the research development, hotspots, and possible future orientation, we performed a scientometric analysis of related publications from 2012 to 2022. Initial information was accessed using the "Analysis Results" and "Create Citation Report" sections of the Web of Science core collection database, which were utilized to find original publications in this field of research. Biblioshiny and VOSviewer software were applied to further analyze and visualize the data. The research addressed a range of topics, including yearly publications, highly cited articles, co-cited references, journals, authors, nations, organizations, and keywords. A total of 883 articles were retrieved. From 2018 to 2021, the annual publication output was abundant and peaked in 2019. Among 111 countries, the USA obtained the highest number of documents issued, total citations, and total link strength. Meanwhile, most of the top 15 institutions, including the top four, are located in the USA. Further, we spotted greater scopes with development potential, including enhancing records to lessen exposure to harmful risks, improving methods for observing lead sources, and elucidating the gradient link between lead poisoning symptoms and concentrations. We anticipate that our research will assist researchers in summarizing previous research and providing perspectives for workable prospective study topics.

Fish and Seafood Safety: Human Exposure to Toxic Metals from the Aquatic Environment and Fish in Central Asia

Toxic metals that are released into aquatic environments from natural and anthropogenic sources are absorbed by aquatic organisms and may threaten the health of both aquatic organisms and humans. Despite this, there have been limited studies on the metal concentrations in fish and humans in Central Asia. This study summarizes the presence of the toxic metals arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb) in aquatic bodies, fish, and seafood products and conducts a risk assessment. While certain areas show a notable increase in fish and seafood consumption, the overall intake in Central Asia remains below recommended levels. However, in regions with high fish consumption, there is a potential for elevated exposure to toxic metals, especially Hg. The risk of exposure to toxic metals in fish and seafood in Central Asia emerges as a significant concern. Comprehensive monitoring, regulation, and remediation efforts are imperative to ensure the safety of water sources and food consumption in the region. Public awareness campaigns and the establishment of dietary guidelines play a crucial role in minimizing the health risks associated with consumption.

Assessment of Essential and Potentially Toxic Elements in Water and Sediment and the Tissues of Sciaena deliciosa (Tschudi, 1846) from the Coast of Callao Bay, Peru

The lorna drum Sciaena deliciosa is a coastal demersal species and one of the underlying artisanal fisheries in some areas of Peru, and is also a source of protein for Peruvian coastal dwellers. The investigation addresses concern about the environmental impact on this fish species and the potential risks to human health through the consumption of contaminated seafood. This research endeavors to assess the concentration of potentially toxic and essential elements in the muscle and liver tissues of S. deliciosa, in addition to the presence thereof in water and sediment capture areas on the coast of Callao, Peru. The study revealed that, in water samples, Ag, Ni, and Zn exceed Peruvian standards, but were below international standards, and Ba, P, Se, and Sn exceed international standards. In the sediments, As, Cd, Pb, Fe, and Zn were above international standards. In the fish, S. delicious muscle demonstrated As, Hg, and Pb exceeding at least one international standard. In the liver, As, Hg, Pb, and Cu exceed international standards. The study approach increased accuracy in risk assessments, offering crucial insights into the interplay between heavy metal pollution, water quality, and animal health, informing risk management strategies. Future studies can explore the long-term effects of heavy metal exposure on different organisms and consider their cumulative impact on health.

Lead and delinquency rates; A spatio-temporal perspective

Juvenile delinquency has significant social costs for perpetrators, victims, and communities. To understand the distribution of delinquency offenses this study considers the spatial clustering of juvenile delinquency with lead, race, and neighborhood deprivation using a longitudinal ecological design (N = 4390) and a hierarchical model implemented in a Bayesian methodology that allows space-time interaction. The results show lead exposure is positively related to delinquency offense rates, and over time delinquency rates have become more concentrated in areas with higher levels of lead exposure and shares of Black or African American residents. The study emphasizes the isolation of neighborhoods with social problems and the importance of monitoring patterns of lead and crime at local levels as communities implement lead exposure mitigation programs.

Involvement of Nrf2 Signaling in Lead-induced Toxicity

Nuclear factor erythroid 2-related factor 2 (Nrf2) is used as one of the main protective factors against various pathological processes, as it regulates cells resistant to oxidation. Several studies have extensively explored the relationship between environmental exposure to heavy metals, particularly lead (Pb), and the development of various human diseases. These metals have been reported to be able to, directly and indirectly, induce the production of reactive oxygen species (ROS) and cause oxidative stress in various organs. Since Nrf2 signaling is important in maintaining redox status, it has a dual role depending on the specific biological context. On the one hand, Nrf2 provides a protective mechanism against metal-induced toxicity; on the other hand, it can induce metalinduced carcinogenesis upon prolonged exposure and activation. Therefore, the aim of this review was to summarize the latest knowledge on the functional interrelation between toxic metals, such as Pb and Nrf2 signaling.

Early-Life Lead Exposure: Risks and Neurotoxic Consequences

BACKGROUND

Lead (Pb) does not have any biological function in a human, and it is likely no safe level of Pb in the human body. The Pb exposure impacts are a global concern for their potential neurotoxic consequences. Despite decreasing both the environmental Pb levels and the average blood Pb levels in the survey populations, the lifetime redistribution from the tissues-stored Pb still poses neurotoxic risks from the low-level exposure in later life. The growing fetus and children hold their innate high-susceptible to these Pb-induced neurodevelopmental and neurobehavioral effects.

OBJECTIVE

This article aims to evaluate cumulative studies and insights on the topic of Pb neurotoxicology while assessing the emerging trends in the field.

RESULTS

The Pb-induced neurochemical and neuro-immunological mechanisms are likely responsible for the high-level Pb exposure with the neurodevelopmental and neurobehavioral impacts at the initial stages. Early-life Pb exposure can still produce neurodegenerative consequences in later life due to the altered epigenetic imprints and the ongoing endogenous Pb exposure. Several mechanisms contribute to the Pb-induced neurotoxic impacts, including the direct neurochemical effects, the induction of oxidative stress and inflammation through immunologic activations, and epigenetic alterations. Furthermore, the individual nutritional status, such as macro-, micro-, or antioxidant nutrients, can significantly influence the neurotoxic impacts even at low-level exposure to Pb.

CONCLUSION

The prevention of early-life Pb exposure is, therefore, the critical determinant for alleviating various Pb-induced neurotoxic impacts across the different age groups.

Neuroepigenetics of ageing and neurodegeneration-associated dementia: An updated review

Gene expression is tremendously altered in the brain during memory acquisition, recall, and forgetfulness. However, non-genetic factors, including environmental elements, epigenetic changes, and lifestyle, have grabbed significant attention in recent years regarding the etiology of neurodegenerative diseases (NDD) and age-associated dementia. Epigenetic modifications are essential in regulating gene expression in all living organisms in a DNA sequence-independent manner. The genes implicated in ageing and NDD-related memory disorders are epigenetically regulated by processes such as DNA methylation, histone acetylation as well as messenger RNA editing machinery. The physiological and optimal state of the epigenome, especially within the CNS of humans, plays an intricate role in helping us adjust to the changing environment, and alterations in it cause many brain disorders, but the mechanisms behind it still need to be well understood. When fully understood, these epigenetic landscapes could act as vital targets for pharmacogenetic rescue strategies for treating several diseases, including neurodegeneration- and age-induced dementia. Keeping this objective in mind, this updated review summarises the epigenetic changes associated with age and neurodegeneration-associated dementia.

Development of a physiologically based toxicokinetic model for lead in pregnant women: The role of bone tissue in the maternal and fetal internal exposure

Epidemiological studies have shown associations between prenatal exposure to lead (Pb) and neurodevelopmental effects in young children. Prenatal exposure is generally characterized by measuring the concentration in the umbilical cord at delivery or in the maternal blood during pregnancy. To assess internal Pb exposure during prenatal life, we developed a pregnancy physiologically based pharmacokinetic (p-PBPK) model that to simulates Pb levels in blood and target tissues in the fetus, especially during critical periods for brain development. An existing Pb PBPK model was adapted to pregnant women and fetuses. Using data from literature, both the additional maternal bone remodeling, that causes Pb release into the blood, and the Pb placental transfers were estimated by Bayesian inference. Additional maternal bone remodeling was estimated to start at 21.6 weeks. Placental transfers were estimated between 4.6 and 283 L.day-1 at delivery with high interindividual variability. Once calibrated, the p-PBPK model was used to simulate fetal exposure to Pb. Internal fetal exposure greatly varies over the pregnancy with two peaks of Pb levels in blood and brain at the end of the 1st and 3rd trimesters. Sensitivity analysis shows that the fetal blood lead levels are affected by the maternal burden of bone Pb via maternal bone remodeling and by fetal bone formation at different pregnancy stages. Coupling the p-PBPK model with an effect model such as an adverse outcome pathway could help to predict the effects on children's neurodevelopment.

Using Artificial Intelligence to Identify Sources and Pathways of Lead Exposure in Children

CONTEXT

Sources and pathways of lead exposure in young children have not been analyzed using new artificial intelligence methods.

OBJECTIVE

To collect environmental, behavioral, and other data on sources and pathways in 17 rural homes to predict at-risk households and to compare urban and rural indicators of exposure.

DESIGN

Cross-sectional pilot study.

SETTING

Knox County, Illinois, which has a high rate of childhood lead poisoning.

PARTICIPANTS

Rural families.

METHODS

Neural network and K-means statistical analysis.

MAIN OUTCOME MEASURE

Children's blood lead level.

RESULTS

Lead paint on doors, lead dust, residential property assessed tax, and median interior paint lead level were the most important predictors of children's blood lead level.

CONCLUSIONS

K-means analysis confirmed that settled house dust lead loadings, age of housing, concentration of lead in door paint, and geometric mean of interior lead paint samples were the most important predictors of lead in children's blood. However, assessed property tax also emerged as a new predictor. A sampling strategy that examines these variables can provide lead poisoning prevention professionals with an efficient and cost-effective means of identifying priority homes for lead remediation. The ability to preemptively target remediation efforts can help health, housing, and other agencies to remove lead hazards before children develop irreversible health effects and incur costs associated with lead in their blood.

Lead Poisoning From Home-Prepared Indian Spices in 3 Families

Spice consumption, along with other environmental factors, can contribute to pediatric lead poisoning. Although public health efforts have increased awareness of contamination of spices, false assumptions regarding the safety of home-prepared spices have emerged. Here, we present the clinical features, family beliefs, and environmental toxicology of 3 spice-associated pediatric lead poisoning cases.

Refining risk estimates for lead in drinking water based on the impact of genetics and diet on blood lead levels using the Collaborative Cross mouse population

Blood lead (Pb) level (BLL) is a commonly used biomarker to evaluate associations with health effects. However, interventions to reduce the adverse effects of Pb require relating BLL to external exposure. Moreover, risk mitigation actions need to ensure protection of more susceptible individuals with a greater tendency to accumulate Pb. Because little data is available to quantify inter-individual variability in biokinetics of Pb, we investigated the influence of genetics and diet on BLL in the genetically diverse Collaborative Cross (CC) mouse population. Adult female mice from 49 CC strains received either a standard mouse chow or a chow mimicking the American diet while being provided water ad libitum with 1000 ppm Pb for 4 weeks. In both arms of the study, inter-strain variability was observed; however, in American diet-fed animals, the BLL was greater and more variable. Importantly, the degree of variation in BLL among strains on the American diet was greater (2.3) than the default variability estimate (1.6) used in setting the regulatory standards. Genetic analysis identified suggestive diet-associated haplotypes that were associated with variation in BLL, largely contributed by the PWK/PhJ strain. This study quantified the variation in BLL that is due to genetic background, diet, and their interactions, and observed that it may be greater than that assumed for current regulatory standards for Pb in drinking water. Moreover, this work highlights the need of characterizing inter-individual variation in BLL to ensure adequate public health interventions aimed at reducing human health risks from Pb.

Lead and arsenic contamination in henna samples marketed in Iran

Since ancient times, people around the world have used natural cosmetics to improve or change the appearance of their nails, skin, and hair. Henna is a plant-based dye that has been used over the centuries for medical and cosmetic purposes. The present work was aimed to investigate the presence of lead (Pb) and arsenic (As) in various types of commonly consumed henna samples in Iran. A total of thirty-nine henna samples from both local and imported products (3 colors in 13 brands) were randomly collected from popular and herbal medicine markets. The atomic absorption spectrometry (AAS) technique was used for the analysis of the samples. The amount of Pb and As in 100% samples was higher than the calculated limit of quantitation (LOQ). The concentrations of Pb and As in the samples were at the ranges of 9.56-16.94 μg/g and 0.25-1.12 μg/g, respectively. The mean level of Pb was higher in black and red products, compared with the green henna. The levels of Pb and As in 53.85% and 7.7% of the henna samples exceeded the permissible limits recommended by the World Health Organization (WHO), respectively. In addition, the mean levels of Pb and As contamination in the imported samples were significantly higher, in comparison to the local henna samples. To our knowledge, this is the first study assessing Pb and As contamination in the henna samples consumed in Iran. Our study demonstrated that there is a potential risk of exposure to Pb through henna in the Iranian consumers.

Are There Sex Differences in Interactive Associations of Environmental Exposure to Lead (Pb), Mercury (Hg), and Manganese (Mn) with GST Genes (GSTP1, GSTT1, and GSTM1) in Relation to ASD in Jamaican Children?

Background

Male preponderance is well-established in children with autism spectrum disorder (ASD). Glutathione S-transferase (GST) genes play a crucial role in suppressing oxidative stress triggered by environmental stressors.

Objective

To determine whether the association between metals and ASD differs by sex and by GST genes.

Methods

Using data from 344 pairs of sex-and age-matched cases and controls, we assessed the association of each metal with ASD or ASD severity, by applying conditional logistic regression (CLR) or general linear models (GLM). Sex was assessed as an effect modifier in separate GST genetic models.

Results

For Pb exposure, using a recessive model for the GSTP1 Ile105Val polymorphism, CLR revealed significant overall interaction between sex and GSTP1 (P = 0.04). However, sex-specific matched odds ratios revealed marginally lower odds of the Val/Val genotype among ASD cases than controls in females (MORfemales= 0.23 (95% CI): 0.05-1.11, P = 0.06), but not among males (MORmales= 1.18 (95% CI): 0.66-2.16, P = 0.57) in the adjusted model. GLMs for Hg exposure detected significant overall interactions in GSTP1 co-dominant and recessive genetic models. For example, the mean difference in ASD severity among children with Val/Val genotype compared to those with Ile/Ile or Ile/Val were MORfemales= -0.26 and MORmales= 1.30, respectively, in the adjusted model.

Conclusion

The association of Pb and Hg with ASD significantly differed by sex under the GSTP1 co-dominant and recessive genetic models. Such findings reflect potential sex differences in metal detoxification mechanisms. Replication is warranted due to the limited sample size of female participants.

What are quantitative traits and how can they be used in autism research?

Quantitative traits are measurable characteristics distributed along a continuous scale thought to relate to underlying biology. There is growing interest in the use of quantitative traits in behavioral and psychiatric research, particularly in research on conditions diagnosed based on reports of behaviors, including autism. This brief commentary describes quantitative traits, including defining what they are, how we can measure them, and key considerations for their use in autism research. Examples of measures include behavioral report scales like the Social Responsiveness Scale and Broader Autism Phenotype Questionnaire, as well as biological measurements, like certain neuroimaging metrics; such measures can capture quantitative traits or constructs like the broader autism phenotype, social communication, and social cognition. Quantitative trait measures align with the Research Domain Criteria (RDoC) approach and can be used in autism research to help gain a better understanding of causal pathways and biological processes. They can also be used to aid identification of genetic and environmental factors involved in such pathways, and thereby lead to an understanding of influences on traits across the entire population. Finally, in some cases, they may be used to gauge treatment response, and assist screening and clinical characterization of phenotype. In addition, practical benefits of quantitative trait measures include improved statistical power relative to categorical classifications and (for some measures) efficiency. Ultimately, research across autism fields may benefit from incorporating quantitative trait measures as a complement to categorical diagnosis to advance understanding of autism and neurodevelopment.

Firearm-related lead exposure and pediatric lead levels in Massachusetts: A decade of evidence (2010-2019)

The US has more firearms than any other country in the world and uses lead ammunition almost exclusively. Lead exposure is a significant public health concern and children are at the greatest risk given their exposure to take-home lead. Firearm-related take-home lead exposure may be one of the greatest influences on elevated pediatric blood lead levels. For this ecological and spatial investigation of the relationship between firearm licensure rates as a proxy for firearm-related lead exposure and prevalence of children with blood lead levels ≥5 μg/dL in 351 cities/towns in Massachusetts, we used 10 years of data (2010-2019). We examined this relationship against other known contributors to pediatric lead exposure including old housing stock (lead paint/dust), occupations, and lead in water. Pediatric blood lead levels were positively correlated with licensure, poverty, and certain occupations and negatively correlated with lead in water and police or firefighter employment. Firearm licensure was a major significant predictor of pediatric blood lead alone (β = 0.13; 95% CI, 0.10, 0.17) and across all regression models. The final model predicted over half the variation in pediatric blood lead (Adjusted R2 = 0.51). Negative binomial analysis found cities/towns with more firearms had higher pediatric blood lead levels (highest quartile fully adjusted prevalence ratio ((aPR) = 1.18; 95% CI, 1.09, 1.30) with a significant increase in pediatric blood lead per increase in firearms (p < 0.001). There were no significant spatial effects, suggesting that although there could be other factors impacting elevated pediatric blood lead, they are unlikely to influence spatial associations. Our paper provides compelling evidence of a potential and dangerous link between lead ammunition and child blood lead levels and is the first to do so using multiple years' worth of data. More research is required to substantiate this relationship on the individual-level and into prevention/mitigation.

Prenatal blood lead levels and Birth Weight: a Meta-analysis study

Purpose

Lead, a known toxic metal, causes several adverse reproductive effects, including low birth weight. Fortunately, the exposure level has sharply decreased during the recent decades, but a definitive safe level did not introduce for pregnant women yet. The current meta-analysis study aimed to conduct a quantitative estimation of maternal and umbilical cord blood lead effects on birth weight.

Methods

Two researchers have independently searched the scientific literature for retrieving related studies using the PRISMA criteria for data extraction. Twenty-one full-text articles were selected from primary 5006 titles, limited by the English language and published between 1991 and 2020 on humans.

Results

The pooled mean of maternal and umbilical cord blood lead levels were 6.85 µg/dL (95% CI: 3.36-10.34) and 5.41 µg/dL (95%CI: 3.43-7.40), respectively. The correlation coefficient analysis showed a significant inverse association between the mean maternal blood lead level and birth weight, which was confirmed by Fisher Z-Transformation analysis (-0.374, 95% CI: -0.382, -0.365, p < 0.01). In addition, a significantly lower birth weight (∆: 229 gr, p < 0.05) was found in the relatively high level of maternal blood lead than in low-level exposure (> 5 µg/dL vs. ≤ 5 µg/dL, respectively).

Conclusion

In short, the present study findings suggest an increasing maternal blood lead levels could be a potential risk factor for reducing birth weight. Thus, pregnant women should avoid lead exposure, as much as possible.

Supplementary information

The online version contains supplementary material available at 10.1007/s40201-022-00843-w.

Lead immobilization for environmentally sustainable perovskite solar cells

Lead halide perovskites are promising semiconducting materials for solar energy harvesting. However, the presence of heavy-metal lead ions is problematic when considering potential harmful leakage into the environment from broken cells and also from a public acceptance point of view. Moreover, strict legislation on the use of lead around the world has driven innovation in the development of strategies for recycling end-of-life products by means of environmentally friendly and cost-effective routes. Lead immobilization is a strategy to transform water-soluble lead ions into insoluble, nonbioavailable and nontransportable forms over large pH and temperature ranges and to suppress lead leakage if the devices are damaged. An ideal methodology should ensure sufficient lead-chelating capability without substantially influencing the device performance, production cost and recycling. Here we analyse chemical approaches to immobilize Pb2+ from perovskite solar cells, such as grain isolation, lead complexation, structure integration and adsorption of leaked lead, based on their feasibility to suppress lead leakage to a minimal level. We highlight the need for a standard lead-leakage test and related mathematical model to be established for the reliable evaluation of the potential environmental risk of perovskite optoelectronics.

Complexities in attributing lead contamination to specific sources in an industrial area of Philadelphia, PA

Globally, lead (Pb) contamination is one of the top ten chemical exposure issues affecting public health. The identification of specific Pb sources provides valuable information to determine assignment of liability for site cleanup, improve sampling plans and develop remedial strategies. This paper examines Pb concentrations and Pb isotopic data from samples collected at and near the site of a Pb paint production facility with a long operating history. Although high soil Pb concentrations were found at the site, Pb concentrations in surrounding neighborhoods did not simply decline with distance from the site. We evaluated soil concentrations and isotopic mixing lines to explore potential sources of Pb pollution. Three-isotope plots showed overlap of site samples and the surrounding neighborhood, consistent with pollution from the facility affecting offsite soils. A major challenge in separation of potential sources, however, is that the isotopic signatures of other potential Pb sources fall within the range of the soil data. The long operational site history, soil disturbances, the presence of nearby smelters, and other local and remote sources affect identification of lead sources. This analysis demonstrates that source attribution can be confounded by incomplete site and material sourcing information. An integrated approach that includes in-depth site characterization and an evaluation of historical activities (e.g., Pb ores used over time, amounts of Pb emitted by all area smelters, land use changes, and soil disturbances) is important for determining source attribution. This analysis provides insight into future site investigations where soil lead contamination has resulted from a long industrial history in an urban setting.

Silicon fertilization enhances the resistance of tobacco plants to combined Cd and Pb contamination: Physiological and microbial mechanisms

Remediation of soil contaminated with cadmium (Cd) and lead (Pb) is critical for tobacco production. Silicon (Si) fertilizer can relieve heavy metal stress and promote plant growth, however, it remains unknown whether fertilization with Si can mitigate the effects of Cd and Pb on tobacco growth and alter microbial community composition in polluted soils. Here we assessed the effect of two organic (OSiFA, OSiFB) and one mineral Si fertilizer (MSiF) on Cd and Pb accumulation in tobacco plants, together with responses in plant biomass, physiological parameters and soil bacterial communities in pot experiments. Results showed that Si fertilizer relieved Cd and Pb stress on tobacco, thereby promoting plant growth: Si fertilizer reduced available Cd and Pb in the soil by 37.3 % and 28.6 %, respectively, and decreased Cd and Pb contents in the plant tissue by 42.0-55.5 % and 17.2-25.6 %, resulting in increased plant biomass by 13.0-30.5 %. Fertilization with Si alleviated oxidative damage by decreasing malondialdehyde content and increasing peroxidase and ascorbate peroxidase content. In addition, Si fertilization increased photosynthesis, chlorophyll and carotenoid content. Microbial community structure was also affected by Si fertilization. Proteobacteria and Actinobacteria were the dominant phylum in the Cd and Pb contaminated soils, but Si fertilization reduced the abundance of Actinobacteria. Si fertilization also altered microbial metabolic pathways associated with heavy metal resistance. Together, our results suggest that both organic and mineral Si fertilizers can promote tobacco growth by relieving plant physiological stress and favoring a heavy metal tolerant soil microbial community.

Reference intervals for cd, hg, Mn and Pb in the general children population (3-14 years) of Kinshasa, Democratic Republic of Congo (DRC) between June 2019 and June 2020

The reference intervals (RIs), proposed by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and the International Union of Pure and Applied Chemistry (IUPAC), were derived for Cd, Hg, Mn and Pb in the blood and urine of the children population living in Kinshasa (n = 200, aged 3-14 years with 97 girls). Levels of metals were measured using coupled plasma mass (ICP-MS). In blood, the proposed RIs [P5-P95 (GM)] were 0.022-1.112 μg/L (0.074), 35.69-144.50 μg/L (71.43), 0.060 to 1.161 μg/L (0.208) and 6.597-15.740 μg/L (9.882) for Cd, Pb, Hg and Mn, respectively. Urinary levels [(P5-P95 (GM)] were 0.082-1.530 μg/L (0.366) for Cd, 1.827-18.500 μg/L (5.458) for Pb, 0.323-1.953 μg/L (0.709) for Hg and 0.070 to 1.703 μg/L (0.186) for Mn. As compared to the CDC updated blood Pb reference value (35 μg/L), Pb levels remain higher of public health concern. Cd and Mn levels were similar to those found in the same city in 2015 and databases involving non-occupationally exposed populations from other countries. Hg levels significantly lower than those found in the same city in 2015, probably due to exclusion criteria of metal exposure applying in the present survey (occupationally exposed to the studied metals, smoking habits, amalgam tooth fillings, fish consumption habit more than one time per week, etc.). These background metal exposures will be useful for future occupational and/or environmental surveys as well as undertaking a reliable regulation of chemical exposure in Kinshasa via a national HBM program.

Provision of information by midwives for pregnant women in England on guidance on foods/drinks to avoid or limit

BACKGROUND

The National Health Service (NHS) website gives guidance for pregnant women in England on foods/drinks to avoid or limit because of microbiological, toxicological or teratogenic hazards. These include, for example, some types of soft cheeses, fish/seafood and meat products. This website and midwives are trusted sources of information for pregnant women, but the ways in which midwives can be supported to provide clear and accurate information are unknown.

AIMS

The aims were to: (1) determine midwives' accuracy of recall of information and confidence in delivering the guidance to women; (2) identify barriers to provision; (3) identify the ways in which midwives provide this information to women.

METHODS

Registered Midwives practicing in England completed an online questionnaire. Questions included those on what information they provided and their confidence in delivering it, the ways they provided information on foods to avoid/limit, their recall of some of the guidance, and what resources they used. Ethics approval was given by the University of Bristol.

RESULTS

More than 10% of midwives (n = 122) were 'Not at all confident/Don't know' in providing advice about ten items, including game meat/gamebirds (42% and 43%, respectively), herbal teas (14%) and cured meats (12%). Only 32% correctly recalled overall advice on eating fish, and only 38% the advice on tinned tuna. The main barriers to provision were lack of time in appointments and lack of training. The most usual methods of disseminating information were verbal (79%) and signposting to websites (55%).

CONCLUSION

Midwives were often unconfident about their ability to provide accurate guidance, and recall on items tested was frequently mistaken. Delivery of guidance by midwives on foods to avoid or limit needs to be supported by appropriate training and access to resources, and sufficient time in appointments. Further research on barriers to the delivery and implementation of the NHS guidance is needed.

Intermittent Lead Exposure Induces Behavioral and Cardiovascular Alterations Associated with Neuroinflammation

The nervous system is the primary target for lead exposure and the developing brain appears to be especially susceptible, namely the hippocampus. The mechanisms of lead neurotoxicity remain unclear, but microgliosis and astrogliosis are potential candidates, leading to an inflammatory cascade and interrupting the pathways involved in hippocampal functions. Moreover, these molecular changes can be impactful as they may contribute to the pathophysiology of behavioral deficits and cardiovascular complications observed in chronic lead exposure. Nevertheless, the health effects and the underlying influence mechanism of intermittent lead exposure in the nervous and cardiovascular systems are still vague. Thus, we used a rat model of intermittent lead exposure to determine the systemic effects of lead and on microglial and astroglial activation in the hippocampal dentate gyrus throughout time. In this study, the intermittent group was exposed to lead from the fetal period until 12 weeks of age, no exposure (tap water) until 20 weeks, and a second exposure from 20 to 28 weeks of age. A control group (without lead exposure) matched in age and sex was used. At 12, 20 and 28 weeks of age, both groups were submitted to a physiological and behavioral evaluation. Behavioral tests were performed for the assessment of anxiety-like behavior and locomotor activity (open-field test), and memory (novel object recognition test). In the physiological evaluation, in an acute experiment, blood pressure, electrocardiogram, and heart and respiratory rates were recorded, and autonomic reflexes were evaluated. The expression of GFAP, Iba-1, NeuN and Synaptophysin in the hippocampal dentate gyrus was assessed. Intermittent lead exposure induced microgliosis and astrogliosis in the hippocampus of rats and changes in behavioral and cardiovascular function. We identified increases in GFAP and Iba1 markers together with presynaptic dysfunction in the hippocampus, concomitant with behavioral changes. This type of exposure produced significant long-term memory dysfunction. Regarding physiological changes, hypertension, tachypnea, baroreceptor reflex impairment and increased chemoreceptor reflex sensitivity were observed. In conclusion, the present study demonstrated the potential of lead intermittent exposure inducing reactive astrogliosis and microgliosis, along with a presynaptic loss that was accompanied by alterations of homeostatic mechanisms. This suggests that chronic neuroinflammation promoted by intermittent lead exposure since fetal period may increase the susceptibility to adverse events in individuals with pre-existing cardiovascular disease and/or in the elderly.

Associations of Prenatal Chemical and Nonchemical Stressors with Early-Adulthood Anxiety and Depressive Symptoms

BACKGROUND

Prenatal exposure to environmental chemicals may increase risk of childhood internalizing problems, but few studies have explored the potential for longer-term consequences of such exposures.

OBJECTIVE

We evaluated associations between prenatal organochlorine and metal levels and early adulthood internalizing symptoms, considering whether sociodemographic/nonchemical stressors modified these associations.

METHODS

Participants were 209 young adults, born (1993-1998) to mothers residing in or near New Bedford, Massachusetts. As part of the early-adult assessment, self-reported anxiety (7-item Generalized Anxiety Disorder scale) and depressive (8-item Patient Health Questionnaire) symptoms (≥10: elevated symptoms) were ascertained. We previously analyzed levels of cord serum organochlorines [hexachlorobenzene, dichlorodiphenyldichloroethylene (p,p'-DDE), polychlorinated biphenyls (ΣPCB4: sum of congeners 118, 138, 153, 180)] and whole blood lead shortly after participants' birth, and levels of cord whole blood manganese from archived samples at the time of the adolescent study visit. We used modified Poisson regression models and quantile g-computation, adjusting for sociodemographics, and explored whether biological sex, race/ethnicity (proxy for unmeasured consequences of racism), prenatal social disadvantage (assessed when participants were neonates), and quality of the home environment (assessed during adolescence) modified these associations.

RESULTS

Participants were (mean±standard deviation) 22.1±1.5 y old, 76% Non-Hispanic White, and 67% female. Prenatal hexachlorobenzene, p,p'-DDE, and lead exposures were moderately associated with increased risk of elevated anxiety symptoms. There were strata-specific associations for prenatal social disadvantage and quality of home environment such that adverse associations of p,p'-DDE and lead and the overall mixture with anxiety and depressive symptoms were largely only evident in those with lower nonchemical stress [e.g., risk ratio and 95% confidence interval (CI) per doubling p,p'-DDE for anxiety: 1.54 (95% CI: 1.20, 1.99) in high-quality home environments and 0.77 (95% CI: 0.51, 1.16) in low-quality home environments]. Associations between prenatal hexachlorobenzene and p,p'-DDE and anxiety symptoms were stronger for underrepresented racial/ethnic group participants vs. Non-Hispanic Whites. We found minimal evidence for sex-specific effects, and no consistent associations with manganese or ΣPCB4.

DISCUSSION

Prenatal organochlorine pesticides and lead exposure possibly increases risk of internalizing problems, particular anxiety symptoms, in young adults. Varying risk was observed by sociodemographic/nonchemical stressor strata, demonstrating the importance of considering interactions between chemical and other stressors. https://doi.org/10.1289/EHP11171.

Association between lower-level of environmental lead exposure and reactive and proactive aggression in youth: Sex differences

Lead exposure during childhood has been associated with a variety of negative outcomes, including antisocial/aggressive behavior. However, different subtypes of antisocial behavior have been found to have different neurobiological correlates, and it is unclear whether lead exposure is related to specific subtypes of aggressive behavior. The objective of the study was to examine relationships between childhood blood lead levels (BLL) and proactive and reactive aggression. Further, given prior findings of sex differences in the effects of lead exposure, we examine whether there are sex differences in these relationships. In a sample of 818 youth (47.2% girls) ages 10-13 in China, we assessed BLL and administered the Reactive Proactive Aggression Questionnaire. Results show that BLLs were associated with reactive, but not proactive aggression. There was a significant interaction between BLL and sex in predicting aggression; boys with higher BLL scored higher in both proactive and reactive aggression than boys with lower BLL, but these differences were not present for girls. These findings suggest that lead exposure may have broad effects on antisocial behavior, but that boys may be more susceptible than girls. These findings may provide insights to identifying protective factors that could be potential targets for intervention.