Children's exposure to environmental lead: A review of potential sources, blood levels, and methods used to reduce exposure

Socioeconomic disparities in hygiene behaviors and their association with urinary metal levels in Chinese preschoolers

The relationship between personal hygiene and the risk of communicable diseases is well established, with socioeconomic status recognized as a significant factor in this context. Given that infectious diseases, environmental pollutants, and metals share pathways of entry into the human body, this study sought to investigate the correlation between hygiene practices and urinary metal levels in preschool-aged children. A cross-sectional analysis involving 1,477 preschoolers was conducted where urinary concentrations of 23 metals were determined using inductively coupled plasma mass spectrometry. Information about hygiene practices and socioeconomic status was collected from the children's guardians. The results of regression analyses revealed a significant association between improved hygiene practices and lower urinary levels of chromium, iron, and antimony (all p < 0.05), as well as with high household per capita monthly income. Compared to children from low-income families, children from high-income families had better hygiene behaviors (all p < 0.05). In low-income families, children with good hygiene behaviors had lower urinary chromium, iron, and antimony levels (all p < 0.05). Mediation analysis further suggested that bathing and hygiene practices could explain about 7.56% to 28.24% of the effects of urinary chromium, iron, and antimony levels related to household per capita monthly income (all p < 0.05). These findings emphasized that good hygiene behaviors might be a feasible way to reduce heavy metal exposure among children.

Standards for levels of lead in soil and dust around the world

Lead poisoning is a serious environmental health problem in every country in the world. Exposure to lead results in neurocognitive and behavioral changes, has adverse effects on the immune system, causes anemia, hypertension and perturbs other organ systems. The effects of lead poisoning are most critical for children because their bodies are growing and developing, and particularly because agents that reduce cognitive function and attention span as well as promote disruptive behavior will have life-long consequences. Lead exposure, especially to children, is a major health disparity issue. If the next generation starts with reduced cognitive ability, there will be significant barriers for development of skills and country-wide development. While there are many sources of exposure to lead, the commonest source is lead in soil and dust. Since lead is an element, it does not go away and past releases of lead into the environment remain as soil and dust contamination. This is an especially important route of exposure to children because children regularly play in soil and are exposed via hand-to-mouth activity. In addition to indoor sources of lead, contaminated soil is tracked on shoes or feet and blown by air currents into homes, accumulating in household dust which is a major source of exposure for both children and adults. The purpose of this review is to determine standards presumed to be health protective for lead and dust in different countries. We find that many countries have no standards for lead in soil and dust and rely on standards set by the World Health Organization or the US Environmental Protection Agency, and these standards may or may not be enforced. There is considerable variation in standards set by other countries.

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.

Associations of combined exposure to selected metal mixtures with thyroid hormones in children: a cross-sectional study in China

Background

Exposure to several metal elements has been found to be associated with thyroid hormone homeostasis. However, evidence for combined exposure is inconclusive, especially for children.

Objective

To examine the individual and joint effects of blood metal elements on thyroid hormones in children.

Methods

A total of 12,470 children aged 0-14 were collected from January 2018 to December 2021 in Hunan Children's Hospital. The concentrations of lead (Pb), iron (Fe), calcium (Ca), copper (Cu), zinc (Zn) and magnesium (Mg) in blood were detected via atomic absorption spectrometry (AAS). The levels of thyroid stimulating hormone (TSH), triiodothyronine (TT3, FT3) and total and free thyroxine (TT4, FT4) were measured by electrochemiluminescence immunoassay (ECLIA). Generalized linear regression (GLR) model and Quantile-based g-computation (QGC) were employed to estimate the association between metal exposure and thyroid hormone homeostasis.

Results

GLR model showed that a unit increase in ln-transformed Fe was associated with increases in TT3 (β = 0.163; P FDR < 0.001), TT4 (β = 12.255; P FDR < 0.001) and FT3 (β = 0.615; P FDR < 0.001), as well as decreases in TSH (β = -0.471; P FDR = 0.005) and FT4 (β = -1.938; P FDR < 0.001). The result of QGC analysis indicated a positive relationship of the ln-transformed concentration of metal mixture with the levels of TT3 (β = 0.018; P = 0.012), TT4 (β = 2.251; P < 0.001) and FT3 (β = 0.074; P < 0.001) in children. Fe was the predominant contributor among the metal mixture with positive contributions to TT3 (weight = 0.439), TT4 (weight = 0.502) and FT3 (weight = 0.450).

Conclusions

The combined metal exposure was associated with increased levels of TT3, TT4, and FT3 in children and Fe appeared to be the major contributor. Further studies are warranted to confirm our findings and elucidate the underlying mechanisms.

Stability of Lead(IV) Oxide in a Lead Pipe Scale and Its Potential Role in Corrosion Control

Lead(IV) oxide (PbO2) is an important component of the scale in many lead pipes used for water supply. Promoting conditions that maintain its stability could be an effective method for limiting lead release. In this study, we applied a method that combined electrochemical and free chlorine conditioning to form PbO2 scales on coupons. Lead coupons were then used to investigate the impacts of water stagnation time and residual free chlorine on PbO2 stability. Free chlorine depletion and associated lead release were investigated from 30 min to 5 days for different initial free chlorine concentrations (0.5-3.0 mg/L as Cl2). There was a lag time of up to 24 h between free chlorine depletion and observed lead increases. With daily readjustment of free chlorine to 0.2 mg/L or higher, the stability of the PbO2 scale on the lead coupon was maintained and dissolved lead remained consistently below 10 μg/L. This study provides information on key factors affecting reductive dissolution of PbO2 present in lead scales. It bridges the theoretical threshold free chlorine to maintain PbO2 stability with experimental results and provides implications for actual water quality monitoring and household drinking water use.

Time-trends of blood lead levels from 2020 to 2023 in pregnant and breastfeeding women from Adjara, Georgia-A birth registry-based study

BACKGROUND

In response to substantial lead exposure, the autonomous republic of Adjara in Georgia initiated complementary blood lead level (BLL) testing for pregnant women as part of their antenatal care services in 2020.

OBJECTIVES

To study the background BLLs in pregnant and breastfeeding women in Adjara and explore the time-trends of BLLs from September 2020 to July 2023.

METHODS

We used data on BLLs during pregnancy or postpartum from the lead screening program in Adjara, combined with data from the Georgian Birth Registry, totaling 9,510 women. To study the temporal changes in BLLs, we used independent samples t-tests and chi-square tests.

RESULTS

In 2020, the mean (standard deviation [SD]) BLL was 8.8 (5.4) μg/dL, declining annually by 1.0-2.2 μg/dL to reach 3.6 (2.5) μg/dL in 2023. The prevalence of pregnant women with BLLs ≥3.5, ≥5.0, and ≥10.0 μg/dL also decreased from 2020 to 2023. Specifically, 21.2% of women in their first trimester had BLLs ≥10 μg/dL in 2020, compared with 2.3% in 2023. Similarly, 73.5% had BLLs ≥5.0 μg/dL in 2020, which declined to 20.4% in 2023. Lastly, 89.1% had BLLs ≥3.5 μg/dL in 2020, decreasing to 38.6% in 2023.

DISCUSSION

In 2023, nearly 40% of women in their first trimester had BLLs of ≥3.5 μg/dL, a level considered the reference value in the United States (US) and corresponding to the 97.5th percentile among US children. From 2020 to 2023, the mean BLL in pregnant women decreased by 59%, accompanied by a considerable decline in the prevalence of women with BLLs ≥3.5, ≥5.0, and ≥10.0 μg/dL. Despite the encouraging downward trend in BLLs throughout the study period, our data indicate that a considerable number of fetuses continue to be exposed to harmful levels of lead and that lead exposure remains a significant public health challenge in Adjara.

Harnessing microbes for heavy metal remediation: mechanisms and prospects

Contamination by heavy metals (HMs) poses a significant threat to the ecosystem and its associated micro and macroorganisms, leading to ill effects on humans which necessitate the requirement of effective remediation strategies. Microbial remediation leverages the natural metabolic abilities of microbes to overcome heavy metal pollution effectively. Some of the mechanisms that aids in the removal of heavy metals includes bioaccumulation, biosorption, and biomineralization. Metals such as Cd, Pb, As, Hg, and Cr are passively adsorbed by energy independent process onto the surface by exopolysaccharide sequestration or utilizing energy to transfer metals into the cell and interact with the biomolecules to be sequestered, or being converted into its various valencies, thereby reducing the toxicity. Application of hyperaccumulators has shown to be effective in the removal of HMs especially while augmented with microbes to the rhizosphere region. Omics studies which include metabolomics and metagenomics provide significant information about the microbial diversities and metabolic processes involved in heavy metal remediation, allowing the development of more reliable and sustainable bioremediation approaches. This review also summarizes the recent advancements in microbial remediation, including genetic engineering and nanotechnology that has revolutionized and offered an unprecedented control and precision in the removal of HMs. These innovations hold a promising stand for enhancing remediation efficiency, scalability, and cost-effectiveness.

Tracking Childhood Lead Exposure in Early Industrial Romanians

Childhood lead exposure has been linked to severe adverse health outcomes throughout life. Measurements of lead in teeth have established that individuals living in contaminated environments show higher levels compared to individuals living further away, although less is known about when individuals are most susceptible to these exposures. We examined lead (Pb208) concentrations (ppm) in teeth over the first 2.5 years of life in 16 children born in the late 19th to early 20th century throughout Romania. This period of intense industrialization was characterized by increases in mining, coal burning, and oil refining-activities that contaminate air, water, and food with Pb. We hypothesized the distance from an operational mine or oil refinery, or being born in a city, would be positively associated with cumulative dentine Pb exposure (CDPE). We also predicted that Pb exposures would peak in the first six months of life when gastrointestinal (GI) absorption of Pb is likely highest. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) of sectioned tooth dentine followed by Bayesian statistical analyses revealed that living 30 km or more from a mine or oil refinery did not explain CDPE. However, being born in a city explained 42% of CDPE. All individuals showed maximum Pb exposures after six months of age, likely due to contaminated solid food and/or non-milk liquids. This research demonstrates how tooth formation can be coupled with comprehensive elemental mapping to analyse the context and timing of early-life neurotoxicant exposures, which may be extended to well-preserved teeth from clinical and historic populations.

Investigating Trace and Macro-element Composition of Herbal and Nutraceutical Dietary Supplements Marketed in Oman: Insights into Safety and Labeling

With the global increase in the use of dietary supplements to provide nutrients in one's regular diet, these supplements' potential health risks and benefits have become a topic of significant interest. Interestingly, as dietary supplements, the Food and Drug Administration (FDA) in the United States (USA), Europe, and most countries do not require manufacturers and distributors to obtain approval or provide safety assessments before marketing those products. This research explores for the first time 16 heavy, trace and macro-elemental contents, namely, As, Ni, Cd, Pb, Cu, Co, Mn, Cr, Zn, V, Fe, Al, K, Na, Mg, and Ca, within 24 nutraceutical and herbal supplements marketed in Oman. The research is focusing on ensuring their compositions, concentrations, and freedom of toxic elements. ICP-OES was utilized, preceded by a microwave digestion technique to digest the samples in concentrated HNO3 and HCl (3:1, v/v). The method was validated within linear ranges of 0.03-5.00 ppm and 1.0-200.0 ppm for micro- and macro-elements, respectively, with %recoveries ranging from 90 to 104%. The limits of detection ranged from 0.01 to 0.09 and 0.14 to 0.30 ppm, while the limits of quantification ranged from 0.03 to 0.28 and 0.46 to 0.91 ppm for micro- and macro-elements, respectively. The detected levels were compared to online databases for risk assessment. Although As and Cd were not detected in all samples, Pb was found in nine samples, with some exceeding regulated limits of exposure. About 80% of the samples contained Al, of which two samples were susceptible to serious health risks of exceeding exposure limits in their compiled doses. The locally harvested Omani herbal supplements revealed significant amounts of Zn, Mg, Mn, and Cu. The results highlighted the potential risks associated with both dosage compliance and labeling discrepancies.

Association between breakfast skipping and blood levels of lead and cadmium in children and adolescents aged 6-17 years: Results from the National Health and Nutrition Examination Survey 2013-2018

INTRODUCTION

Previous research suggests that fasting increases lead absorption in the gastrointestinal tract, and that regularly eating meals may reduce blood lead. However, there is insufficient evidence linking breakfast status and blood-metal levels in children. We assessed the cross-sectional association between breakfast consumption status and children and adolescent's blood levels of lead and cadmium. We also explored blood hemoglobin, serum ferritin, and age group as potential effect modifiers of these associations.

METHODS

This analysis included children and adolescents aged 6-17 years who participated in the National Health and Nutrition Examination Survey (NHANES) cycles 2013-2018 with complete data on breakfast consumption status (consumers vs. skippers), blood metals, and covariates (N=3722). Blood metal variables were log-transformed. Crude and covariate-adjusted, survey-weighted linear regression models were conducted for each blood metal outcome. Potential effect modification was explored using stratification.

RESULTS

Overall fewer participants reported skipping breakfast (n=719) than eating breakfast (n=3003). Mean (SE) concentrations of blood lead and cadmium (µg/L) were 0.63 (0.01) µg/dL and 0.13 (0.00) µg/L, respectively. Children and adolescents who skipped breakfast were more likely to be female (51.2%), older (mean 12.2 years, SE = 0.1), have a higher body mass index (mean 22.8 kg/m2, SE = 0.2), and a lower income-poverty ratio (mean 1.7, SE = 0.1) than breakfast consumers. No associations between breakfast consumption and any of the blood metals were found. When stratified by age (≤ 10, 11-13, and 14-17 years), children aged 11-13 years who consumed breakfast had lower log-transformed blood lead levels [β = -0.14 µg/L; 95% CI: (-0.25, -0.03)] compared to children of the same age who skipped breakfast.

CONCLUSION

Children 11-13 years-old who were breakfast consumers had lower blood lead levels compared to children of the same age who skipped breakfast. Our results support that encouraging breakfast consumption among school-age children may contribute to lower blood lead levels.

Enhancing copper and lead adsorption in water by in-situ generation of calcium carbonate on alginate/chitosan biocomposite surfaces

Chitosan (CS) and sodium alginate (SA)-based biocomposites (CSA) were prepared with the in-situ generation of Calcium Carbonate (CSAX_Ca) through a simple, straightforward, economical, and eco-friendly procedure. Different drying conditions (X) were tested to achieve suitable structural and surface characteristics to enhance adsorption capacity: freeze-dried (L), vacuum-dried with methanol (M), and freeze-dried + vacuum-dried with methanol (LM). Temperature and adsorbent dosage effects on the adsorption capacity of Cu2+ or Pb2+ were examined. Results showed that the higher-yielding biocomposite (CSALM_Ca) exhibited rapid adsorption and good diffusion properties, achieving removal above 90 % within contaminant initial concentration ranges of 10-100 mg/L. At 35 °C, a pseudo-second-order kinetic and the Langmuir model effectively described kinetics and isotherms, revealing maximum adsorption (qe, max) of 429 mgCu2+/L and 1742 mgPb2+/g. Characterization through FTIR, XRD, and SEM of the as-prepared adsorbents confirmed the presence of CaCO3 in vaterite and calcite forms and the influence of drying conditions on the material morphology. Post-adsorption material characterization, in combination with adsorption findings, revealed chemisorption processes involving Ca2+ ion exchange for Cu2+ or Pb2+, resulting in surface-insoluble compounds. The best-performing material showed that after three reuse cycles, the removal of Cu2+ and Pb2+ decreased to 75 % and 62 %, respectively.

Modulation of Kynurenic Acid Production by N-acetylcysteine Prevents Cognitive Impairment in Adulthood Induced by Lead Exposure during Lactation in Mice

Lead (Pb2+) exposure during early life induces cognitive impairment, which was recently associated with an increase in brain kynurenic acid (KYNA), an antagonist of NMDA and alpha-7 nicotinic receptors. It has been described that N-acetylcysteine (NAC) favors an antioxidant environment and inhibits kynurenine aminotransferase II activity (KAT II, the main enzyme of KYNA production), leading to brain KYNA levels decrease and cognitive improvement. This study aimed to investigate whether the NAC modulation of the brain KYNA levels in mice ameliorated Pb2+-induced cognitive impairment. The dams were divided into four groups: Control, Pb2+, NAC, and Pb2++NAC, which were given drinking water or 500 ppm lead acetate in the drinking water ad libitum, from 0 to 23 postnatal days (PNDs). The NAC and Pb2++NAC groups were simultaneously fed NAC (350 mg/day) in their chow from 0 to 23 PNDs. At PND 60, the effect of the treatment with Pb2+ and in combination with NAC on learning and memory performance was evaluated. Immediately after behavioral evaluation, brain tissues were collected to assess the redox environment; KYNA and glutamate levels; and KAT II activity. The NAC treatment prevented the long-term memory deficit exhibited in the Pb2+ group. As expected, Pb2+ group showed redox environment alterations, fluctuations in glutamate levels, and an increase in KYNA levels, which were partially avoided by NAC co-administration. These results confirmed that the excessive KYNA levels induced by Pb2+ were involved in the onset of cognitive impairment and could be successfully prevented by NAC treatment. NAC could be a tool for testing in scenarios in which KYNA levels are associated with the induction of cognitive impairment.

Designed bacteria based on natural pbr operons for detecting and detoxifying environmental lead: A mini-review

Lead (Pb), a naturally occurring element, is redistributed in the environment mainly due to anthropogenic activities. Pb pollution is a crucial public health problem worldwide due to its adverse effects. Environmental bacteria have evolved various protective mechanisms against high levels of Pb. The pbr operon, first identified in Cupriavidus metallidurans CH34, encodes a unique Pb(II) resistance mechanism involving transport, efflux, sequestration, biomineralization, and precipitation. Similar pbr operons are gradually found in diverse bacterial strains. This review focuses on the pbr-encoded Pb(II) resistance system. It summarizes various whole-cell biosensors harboring artificially designed pbr operons for Pb(II) biomonitoring with fluorescent, luminescent, and colorimetric signal output. Optimization of genetic circuits, employment of pigment-based reporters, and screening of host cells are promising in improving the sensitivity, selectivity, and response range of whole-cell biosensors. Engineered bacteria displaying Pb(II) binding and sequestration proteins, including PbrR and its derivatives, PbrR2 and PbrD, for adsorption are involved. Although synthetic bacteria show great potential in determining and removing Pb at the nanomolar level for environmental protection and food safety, some challenges must be addressed to meet demanding application requirements.

Identifying Sources of Lead Exposure for Children in the Republic of Georgia, with Lead Isotope Ratios

In the Republic of Georgia, a 2018 national survey estimated that more than 40% of children aged 2-7 years had a blood lead concentration (BLC) of more than 5 µg/dL. The objective of this study was to document the feasibility of employing lead isotope ratios (LIRs) to identify and rank the Pb (lead) exposure sources most relevant to children across Georgia. A cross-sectional survey between November 2019 and February 2020 of 36 children previously identified as having BLCs > 5 µg/dL from seven regions of Georgia involved the collection of blood and 528 environmental samples, a questionnaire on behaviours and potential exposures. The LIRs in blood and environmental samples were analysed in individual children and across the whole group to ascertain clustering. A fitted statistical mixed-effect model to LIR data first found that the blood samples clustered with spices, tea, and paint, then, further isotopically distinct from blood were sand, dust, and soil, and lastly, milk, toys, pens, flour, and water. Analysis of the LIRs provided an indication and ranking of the importance of Pb environmental sources as explanatory factors of BLCs across the group of children. The findings support the deployment of interventions aimed at managing the priority sources of exposure in this population.

Environmental health perceptions of urban youth from low-income communities: A qualitative photovoice study and framework

BACKGROUND

Children are amongst the most susceptible groups to environmental exposures, for both immediate and life-course health outcomes. Despite their increased susceptibility, children's knowledge, experiences and voices are understudied. A deeper understanding of children's environmental health perceptions has the potential to better inform policy, develop targeted interventions and improve public health outcomes.

METHODS

In this study, our community-academic partnership used the Photovoice research method to examine how urban children from low-income communities perceive environmental influences on their health. Twenty children, ages 10-12, took photographs and participated in focus group interviews regarding their perspectives on how the environment influences their health.

RESULTS

Qualitative analyses revealed five major thematic categories: environmental exposures, environmental health sentiments, environmental health outcomes, interest in environmental health and environmental health solutions. We used the findings to develop an environmental health perspective theoretical framework that can inform future work designed to promote the environmental health and well-being of children from low-income communities in urban communities.

CONCLUSION

Photovoice enabled children from low-income communities to capture and communicate their environmental health perceptions. These findings have the potential to inform and identify potential targets and opportunities for environmental health interventions and promotion in their communities.

PATIENT OR PUBLIC CONTRIBUTION

Partnerships with community-based organizations were central to the present study. By design, these community-based partners were involved in the conduct and procedures of the study.

Association between mediterranean diet and metal(loid) exposure in 4-5-year-old children living in Spain

Even relatively low levels of metals exposure may impact health, particularly among vulnerable populations such as infants and young children. However, little is known about the interplay between simultaneous metal exposures, common in real-life scenarios, and their association with specific dietary patterns. In this study, we have evaluated the association between adherence to Mediterranean diet (MD) and urinary metal concentrations individually and as an exposure mixture in 713 children aged 4-5-years from the INMA cohort study. We used a validated food frequency questionnaire to calculate two MD indexes scores: aMED and rMED. These indexes gather information on various food groups within the MD and score differently. To measure urinary concentrations of cobalt, copper, zinc, molybdenum, selenium, lead, and cadmium as exposure biomarkers, we used inductively coupled plasma mass spectrometry (ICP-MS), coupled with an ion chromatography (IC) equipment for arsenic speciation analysis. We applied linear regression and quantile g-computation, adjusted for confounders, to analyse the association between MD adherence and exposure to the metal mixture. High adherence to MD such as the quintile (Q) 5 MD was associated with higher urinary arsenobetaine (AsB) levels than Q1, with β values of 0.55 (confidence interval - CI 95% 0.01; 1.09) for aMED and 0.73 (CI 95% 0.13; 1.33) for rMED. Consumption of fish was associated with increased urinary AsB but reduced inorganic arsenic concentrations. In contrast, the aMED vegetables consumption increased urinary inorganic arsenic content. A moderate level of adherence to MD (Q2 and Q3) was associated with lower copper urinary concentrations than Q1, with β values of -0.42 (CI 95% -0.72; -0.11) for Q2 and -0.33 (CI 95% -0.63; -0.02) for Q3, but only with aMED. Our study, conducted in Spain, revealed that adhering to the MD reduces exposure to certain metals while increasing exposure to others. Specifically, we observed increase in exposure to non-toxic AsB, highlighting the significance of consuming fish/seafood. However, it is crucial to emphasize the necessity for additional efforts in reducing early-life exposure to toxic metals, even when adhering to certain food components of the MD.

A global meta-analysis of the correlation between soil physicochemical properties and lead bioaccessibility

Soil physiochemical properties play a vital role in bioaccessibility-based health risk assessment as it can determine the bioaccessibility and the true risk of potentially toxic elements in soil. However, the effects of soil properties on bioaccessibility still remains unclear. In this paper, 17 of the 1454 literatures with 474 samples were identified, screened and reviewed for exploring the correlation between soil physicochemical properties and lead bioaccessibility (BAc_Pb) through a meta-analysis approach. Five soil physicochemical parameters including pH, SOM, Clay, CEC and T-Pb were systematically analyzed using Principal component analysis, Pearson correlation analysis and survival analysis. The results showed that pH of simulated gastric juice is a major source of heterogeneity of the correlation between soil pH and BAc_Pb. In the gastric phase, the effect of alkaline soil on high BAc_Pb (BAc >50%) is more sensitive, and the effect of acidic soil on low BAc_Pb (BAc <50%) is more sensitive. However, in the small intestinal phase, soil pH displays little impacts on BAc_Pb in acidic, alkaline and neutral soils. Although three principal components explained 66.2% and 64.9% of the total variance of the urban, agricultural, and mining soils in gastric and small intestinal phases, respectively, there was no strong evidence that soil type can influence the BAc_Pb. The results of present study provide insights into the correlation between soil properties and BAc_Pb, and prediction of the bioaccessibility and bioavailability of Pb in different types of soil.

Structure, Antiferroelectricity and Energy-Storage Performance of Lead Hafnate in a Wide Temperature Range

Lead hafnate (PbHfO₃) has attracted a lot of renewed interest due to its potential as antiferroelectric (AFE) material for energy storage. However, its room temperature (RT) energy-storage performance has not been well established and no reports on the energy-storage feature of its high-temperature intermediate phase (IM) are available. In this work, high-quality PbHfO₃ ceramics were prepared via the solid-state synthesis route. Based on high-temperature X-ray diffraction data, the IM of PbHfO₃ was found to be orthorhombic, Imma space group, with antiparallel alignment of Pb²⁺ ions along the [001]_cubic directions. The polarization-electric field (P-E) relation of PbHfO₃ is displayed at RT as well as in the temperature range of the IM. A typical AFE loop revealed an optimal recoverable energy-storage density (W_rec) of 2.7 J/cm³, which is 286% higher than the reported data with an efficiency (η) of 65% at 235 kV/cm at RT. A relatively high W_rec value of 0.7 J/cm³ was found at 190 °C with an η of 89% at 65 kV/cm. These results demonstrate that PbHfO₃ is a prototypical AFE from RT up to 200 °C, making it a suitable material for energy-storage applications in a wide temperature range.

High-precision Pb isotopes of drinking water lead pipes: Implications for human exposure to industrial Pb in the United States

Millions of lead (Pb) pipes are still used in the drinking water distribution systems in many regions in the world. Human exposure to Pb from contaminated drinking water continues to be of concern in the United States (U.S.), as illustrated by the widely publicized "Flint Water Crisis" in 2015. The Pb isotopic composition of Pb-pipes potentially can be useful to identify human exposure to Pb from lead service lines (LSLs). In addition, as the LSLs were likely manufactured from similar industrial Pb sources as other Pb objects and materials in the USA, the Pb-pipes isotope data can provide information about the overall isotopic composition of the U.S. industrial Pb. In this work we present high-precision Pb isotope data from Pb-pipes excavated from different U.S. municipalities. The Pb-pipes show an extremely wide range of Pb isotopic compositions, with ²⁰⁶Pb/²⁰⁴Pb ranging from 17.004 to 22.010, ²⁰⁷Pb/²⁰⁴Pb from 15.460 to 15.921, and ²⁰⁸Pb/²⁰⁴Pb from 36.687 to 41.120. The wide isotope range is observed even in a single town, suggesting that no regional Pb isotope patterns can be expected within the continental USA. However, the high-precision MC-ICP-MS Pb data form a clear linear trend that, depending on the context, can be used to identify human Pb exposure. Furthermore, as the linear trend is a result of utilization of Pb ores from different domestic and international sources and secondary recycling of metallic Pb, it is likely representative of the overall isotopic composition of the U.S. industrial Pb pool. Therefore, the identified trend is the most accurate isotope representation of the U.S. anthropogenic Pb at present and can be used as first-order evaluation to determine if a person with elevated blood Pb levels was exposed to U.S. industrial Pb sources.

Heavy metal analysis in of indoor and outdoor dust extracts and cytotoxicity evaluation and inflammation factors on lung, gastric and skin cell lines

Dust particles (DPs) are one of the most important public health concerns in the urban environment. The presence of heavy metals (HMs) on the surface of DPs might increase the health risk of exposure to the DPs. Accordingly, The purpose of this study was to examine the content of HMs in the outdoor and indoor DPs in Neyshabur city and assess the cytotoxic effects of DPs exposure on lung, gastric, and skin cell lines. To this end, the city was divided into three areas, high-traffic, medium-traffic, and low-traffic (rural). The average concentration of the HMs in the indoor DPs were as follows, 655.5 μg g-1 for Zn, 114.6 μg g-1 for Cu, 77.7 μg g-1 for Cr, 108.6 μg g-1 for Ni, 52 μg g-1 for Pb, 12 μg g-1 for Co, and 3.3 μg g-1 for Cd, while the average concentration of Zn, Cu, Cr, Ni, Pb, Co, Cd in the outdoor DPs were 293.7 μg g-1, 200.6 μg g-1, 100.7 μg g-1, 68.4 μg g-1, 44.7 μg g-1, 18.6 μg g-1, 0.25 μg g-1, respectively. A higher concentration of HMs, as well as cytotoxicity, were revealed in the indoor samples compared to outdoor ones. The degree of cytotoxicity of DPs collected from high-traffic areas was higher than that of low and medium-traffic ones. In addition, treatment of AGS and L929 cells with indoor dust samples induced the expression level of inflammatory agents such as TNFα, IL6, and, CYP1A1 genes more than in outdoor dust samples (P < 0.05). Briefly, a higher level of HMs concentration and cytotoxicity effect on the given cell lines was observed in the samples taken from indoor environments and high-traffic areas.

Lead Disrupts Mitochondrial Morphology and Function through Induction of ER Stress in Model of Neurotoxicity

Lead exposure may weaken the ability of learning and memory in the nervous system through mitochondrial paramorphia and dysfunction. However, the underlying mechanism has not been fully elucidated. In our works, with SD rats, primary culture of hippocampal neuron and PC12 cell line model were built up and behavioral tests were performed to determine the learning and memory insults; Western blot, immunological staining, and electron microscope were then conducted to determine endoplasmic reticulum stress and mitochondrial paramorphia and dysfunction. Co-immunoprecipitation were performed to investigate potential protein–protein interaction. The results show that lead exposure may cripple rats’ learning and memory capability by inducing endoplasmic reticulum stress and mitochondrial paramorphia and dysfunction. Furthermore, we clarify that enhanced MFN2 ubiquitination degradation mediated by PINK1 may account for mitochondrial paramorphia and endoplasmic reticulum stress. Our work may provide important clues for research on the mechanism of how Pb exposure leads to nervous system damage.