Childhood lead poisoning and the new Centers for Disease Control and Prevention guidelines for lead exposure

Neighborhood-scale lead (Pb) speciation in Akron, Ohio (USA) soils: primary sources, post-deposition diagenesis, and high concentrations of labile Pb

Lead (Pb) poses a significant risk to infants and children through exposure to contaminated soil and dust. However, there is a lack of information on Pb speciation and distribution at the neighborhood-scale. This work aimed to determine: (1) the distribution of acid-extractable (labile) Pb and other metals ([M]AE) in two neighborhoods in Akron, Ohio (USA) (Summit Lake and West Akron; n = 82 samples); and (2) Pb speciation and potential sources. Total metal concentration ([M]T) and [M]AE was strongly correlated for Pb and Zn (R2 of 0.66 and 0.55, respectively), corresponding to 35% and 33% acid-extractability. Lead and Zn exhibited a strong positive correlation with each other (R2 = 0.56 for MT and 0.68 for MAE). Three types of Pb-bearing phases were observed by electron microscopy: (1) galena (PbS)-like (5-10 μm); (2) paint chip residuals (10-20 μm); and (3) Pb-bearing Fe-oxides (20 μm). Isotope ratio values for PbAE were 1.159 to 1.245 for 206Pb/207Pb, and 1.999 to 2.098 for 208Pb/206Pb, and there was a statistically significant difference between the two neighborhoods (p = 0.010 for 206Pb/207Pb and p = 0.009 for 208Pb/206Pb). Paint and petrol are the dominant sources of Pb, with some from coal and fly ash. Lead speciation and distribution is variable and reflects a complex relationship between the input of primary sources and post-deposition transformations. This work highlights the importance of community science collaborations to expand the reach of soil sampling and establish areas most at risk based on neighborhood-dependent Pb speciation and distribution for targeted remediation.

Blood Homocysteine Levels Mediate the Association Between Blood Lead Levels and Cardiovascular Mortality

Lead is a heavy, toxic metal and its exposure to humans can lead to increased risk of cardiovascular disease development and mortality. Lead exposure has been shown to induce hyperhomocysteinemia (HHCy) which may be a major pathogenic risk for the risk of CVDs. The aim of this study was to investigate whether homocysteine (Hcy) mediates the effect of lead on cardiovascular mortality. A total of 17,915 adults aged ≥ 20 who participated in the National Health and Nutrition Examination Survey (1999 to 2006). Information on mortality was ascertained via probabilistic matching to the death certificates from the National Death Index recorded up to December 31, 2015. Cox proportional hazards regression was performed to assess the association between blood lead levels and mortality. Mediation via Hcy was examined using a logit model. During a mean follow-up of 11.6 years, the incidences of CVD mortality were 0.73, 2.18, 3.03 and 4.94 per 1000 person-years across quarterlies of blood lead levels from low to high. Following multivariable adjustment, blood lead levels were strongly associated with CVD mortality in all mortality models (p-trend < 0.001). This association remained statistically significant after further adjusting for quartiles of homocysteine (model 3; HR 1.38 (95% CI 1.01-1.89) p-trend < 0.001). Furthermore, blood lead levels increased the odds of CVD mortality via homocysteine (indirect effect) (OR 1.42 (95% CI 1.30-1.55)), demonstrating the mediatory effect of homocysteine. This the first study that demonstrates that increased homocysteine mediates nearly half of CVD mortality related to blood lead levels.

Environmental contaminants and child development: Developmentally-informed opportunities and recommendations for integrating and informing child environmental health science

Child environmental health (CEH) science has identified numerous effects of early life exposures to common, ubiquitous environmental toxicants. CEH scientists have documented the costs not only to individual children but also to population-level health effects of such exposures. Importantly, such risks are unequally distributed in the population, with historically marginalized communities and the children living in these communities receiving the most damaging exposures. Developmental science offers a lens and set of methodologies to identify nuanced biological and behavioral processes that drive child development across physical, cognitive, and socioemotional domains. Developmental scientists are also experts in considering the multiple, hierarchically-layered contexts that shape development alongside toxicant exposure. Such contexts and the individuals acting within them make up an overarching "child serving ecosystem" spanning systems and sectors that serve children directly and indirectly. Articulating how biobehavioral mechanisms and social-ecological contexts unfold from a developmental perspective are needed in order to inform CEH translation and intervention efforts across this child-serving ecosystem. Developmentalists can also benefit from integrating CEH science findings in their work by considering the role of the physical environment, and environmental toxicants specifically, on child health and development. Building on themes that were laid out by Trentacosta and Mulligan in 2020, this commentary presents recommendations for connecting developmental and CEH science and for translating such work so that it can be used to promote child development in an equitable manner across this child-serving ecosystem. These opportunities include (1) Using Developmentally-Informed Conceptual Models; (2) Applying Creative, Sophisticated, and Rigorous Methods; (3) Integrating Developmentally-Sensitive Intervention Considerations; and (4) Establishing Interdisciplinary Collaborations and Cross-Sector Partnerships.

Environmental assessment of pediatric Lead exposure in Tehran; a prospective cross-sectional study

Background

Ingestion and inhalation are common routes of exposure for lead in humans. Developing countries still have unacceptably high rates of lead toxicity, especially in children. Studies on probable risk factors of lead poisoning in Iranian children are insufficient. In this study, we aimed to evaluate possible environmental factors in children with high blood lead concentrations living in Tehran and neighboring cities.

Methods

In a prospective cross-sectional study between March 2018 and March 2019 we followed all children referred from two pediatric gastrointestinal clinics with blood lead level (BLL) > 5 μg/dL in metropolitan Tehran to investigate possible environmental risk factors in their home. Household specimens including scratched wall paint, house floor dust, windowsill dust, tap water, and consumed spice were evaluated using atomic absorption method to detect lead concentrations. Epidemiological and environmental data collected through in-depth interviews with parents/guardians. Industrial areas were defined based on municipality maps on industrial places.

Results

Thirty of 56 parents/guardians with BLL > 5 μg/dL agreed to be followed through environmental investigation. The only categorical statistically significant risk factor was a history of lead poisoning in the family and living in an industrial zone. There was a positive correlation between BLL and interior windowsills dust lead level, r = 0.46, p = 0.01. Scratched paint lead level and BLL showed a significant positive correlation, r = 0.50, p = 0.005. House floor dust lead level (median = 77.4, p < 0.001) and interior windowsill dust lead level (median = 291, p = 0.011) were both significantly higher than the environmental protection agency (EPA) standards of 40 μg/ft2, 250 μg/ft2. Interior windowsill dust lead concentrations were significantly higher in industrial areas (p = 0.026).

Conclusion

Children’s playing environment should be cleaned more often to reduce dust. Moreover, specific rules may need to be implemented for paint lead concentrations and air pollution, especially in industrial areas.

Environmental assessment of pediatric Lead exposure in Tehran; a prospective cross-sectional study

BACKGROUND

Ingestion and inhalation are common routes of exposure for lead in humans. Developing countries still have unacceptably high rates of lead toxicity, especially in children. Studies on probable risk factors of lead poisoning in Iranian children are insufficient. In this study, we aimed to evaluate possible environmental factors in children with high blood lead concentrations living in Tehran and neighboring cities.

METHODS

In a prospective cross-sectional study between March 2018 and March 2019 we followed all children referred from two pediatric gastrointestinal clinics with blood lead level (BLL) > 5 μg/dL in metropolitan Tehran to investigate possible environmental risk factors in their home. Household specimens including scratched wall paint, house floor dust, windowsill dust, tap water, and consumed spice were evaluated using atomic absorption method to detect lead concentrations. Epidemiological and environmental data collected through in-depth interviews with parents/guardians. Industrial areas were defined based on municipality maps on industrial places.

RESULTS

Thirty of 56 parents/guardians with BLL > 5 μg/dL agreed to be followed through environmental investigation. The only categorical statistically significant risk factor was a history of lead poisoning in the family and living in an industrial zone. There was a positive correlation between BLL and interior windowsills dust lead level, r = 0.46, p = 0.01. Scratched paint lead level and BLL showed a significant positive correlation, r = 0.50, p = 0.005. House floor dust lead level (median = 77.4, p < 0.001) and interior windowsill dust lead level (median = 291, p = 0.011) were both significantly higher than the environmental protection agency (EPA) standards of 40 μg/ft², 250 μg/ft². Interior windowsill dust lead concentrations were significantly higher in industrial areas (p = 0.026).

CONCLUSION

Children's playing environment should be cleaned more often to reduce dust. Moreover, specific rules may need to be implemented for paint lead concentrations and air pollution, especially in industrial areas.

Low-level exposure to lead, mercury, arsenic, and cadmium, and blood pressure among 8-17-year-old participants of the 2009-2016 National Health and Nutrition Examination Survey

BACKGROUND

Dysregulation of systolic, diastolic blood pressure (SBP, DBP), and pulse pressure (PP) in children may predict elevated blood pressure (BP) in adulthood. Toxicant exposure is widely studied as a risk factor for high BP in adults, but not in children. We assessed the joint associations between lead (Pb), mercury (Hg), arsenic (As), and cadmium (Cd) exposure and SBP, DBP, and PP among 8-17 year-old participants (n = 1642) of the 2009-2016 National Health and Nutrition Examination Survey (NHANES).

METHODS

Participants with at least two BP measures were included. Urinary As and Cd were adjusted for urinary creatinine concentrations. Blood Pb, Hg, and urinary As, Cd were natural log-transformed. Bayesian Kernel Machine Regression (BKMR) analyses were conducted to assess the associations between the toxicant mixture and BP measures. Multivariable regression models assessed the associations between individual toxicants, and the four toxicants simultaneously with each of the outcomes. Interactions with sodium intake were tested.

RESULTS

Exposure to all toxicants was low, with median (5%, 95%) level: Pb, 0.57 (0.26, 1.60) μg/dL; Hg, 0.37 (0.19, 2.12) μg/L; As, 5.61 (1.37, 33.2) μg/g creatinine, Cd, 0.06 (0.03, 0.23) μg/g creatinine. Toxicant mixture showed a statistically significant, inverse association with DBP, but not other BP measures. Linear regressions revealed no association between toxicants, individually or together, and BP measures. No evidence of interaction of sodium intake with any of the toxicants was observed.

CONCLUSIONS

In a nationally representative sample of 8-17 year-olds, we found suggestive inverse association of the mixture of low-level Pb, Hg, As, and Cd, with DBP. Longitudinal studies with multiple toxicants are needed to understand the interactive effects of toxicants on children's BP.

Inaction on Lead Despite the Relevant Knowledge: Predictors, Covariates, and Outreach Implications

Testing residential soil and paint for lead provides actionable information. By showing where and how much lead exists on the residence, it allows one to quantify risk and determine the best ways to reduce exposure along with the corresponding health and financial costs. For these reasons, several federal and state programs offer outreach to audiences on the benefits of testing residential soil and paint for lead. Not all individuals who know about lead’s adverse health effects, however, test their residence for lead, potentially limiting the actionable information that could have helped to reduce their exposure. Such individuals represent a challenge to outreach programs and the broader public health objectives. There is, thus, a need to understand who such individuals are and why they behave this way, allowing us to develop a specialized outreach program that addresses the problem by targeting the relevant sub-population. Using survey data, we quantitatively determine the profiles of individuals who, despite knowing about lead’s adverse health effects, are unlikely to test their residence for lead, finding statistically significant socio-economic predictors and behavioral covariates. We also find a geographic component to it, further helping outreach professionals learn how to allocate their limited resources.

Maternal Δ-aminolevulinic acid dehydratase 1-2 genotype enhances fetal lead exposure and increases the susceptibility to the development of cerebral palsy

Limited epidemiologic studies questioned the association between pre- and postnatal lead exposure and the development of cerebral palsy (CP). Moreover, the genotypes of δ-aminolevulinic acid dehydratase (δ-ALAD) in CP patients and their mothers and their association to the blood lead levels (BLLs) were not previously studied. This study aimed to evaluate the association between δ-ALAD gene polymorphism and BLL in cases of CP and their mothers. A case control study was carried out on 23 CP cases and equal number of healthy matched controls. The mothers of the included children were asked to answer a questionnaire involving the baseline clinical and demographic characteristics. Also, questionnaires were done to detect the sources of environmental lead exposure and screen lead exposure during the pregnancy period. BLL, δ-ALAD enzyme activity, and genetic analysis for ALAD G177C were done for each child and his mother. There was significant (p < 0.001) elevation of BLL in CP cases and their mothers that was positively correlated (r = 0.436, p < 0.05). There were progressive decreases in δ-ALAD activity with increasing BLL in both children and mothers (p < 0.05). There were non-significant (p > 0.05) differences between CP and the control group regarding frequency of ALAD G177C genotypes, while there was a significant (p = 0.04) increase in the frequency of ALAD 1-2 (GC) genotype in the mothers of the CP group associated with high BLL and significant decrease in δ-ALAD activity (p < 0.001). The study can indicate the significance of δ-ALAD gene polymorphism in the prenatal exposure to lead and the affection of the developing brain, pointing to the importance of controlling lead in pregnant women especially those with ALAD 1-2 genotype.

Increased risk for lead exposure in children through consumption of produce grown in urban soils

Childhood Pb exposure is associated with a multitude of poor health outcomes. In food-insecure areas, growing fresh produce in backyard gardens or on vacant industrial properties is seen as an option for parents. The question arises, could Pb accumulate in consumable tissues of common produce when grown in metals-rich soils at concentrations that would pose a risk to children. This study investigated factors contributing to the accumulation of Pb in consumable tissues of nine common produce crops grown in metals-rich soils from backyard gardens and a former industrial property. Pb in consumable tissues was directly quantified at concentrations less than 1 μg g^-1 via X-ray fluorescence (XRF) using protocols specifically developed for use in plant matrices. The accumulation of Pb in prepared raw consumable tissues in three Pb-rich soils was the greatest in modified taproot crops (mean Pb of 11.8 ± 14.6 μg g^-1; turnip, beetroot, radish, carrot), with lesser concentrations in fruits (mean Pb of 2.0 ± 3.0 μg g^-1; tomato, pepper), and potatoes (mean Pb of 0.7 ± 1.1 μg g^-1). An exposure risk evaluation using the USFDA IRL for Pb indicates that consumption of less than 1 g of certain produce grown in this study, including produce grown in garden soils from residential properties, drastically increases the risk of Pb exposure in children. This study further indicates that the proportion of Pb contributed to the daily body burden in children from food is far greater than previously understood, and in all modeled cases, the contribution of Pb from food on a daily basis far outweighs the contribution of Pb from drinking water. For an average child, after addressing over-riding soil/dust impacts, addressing food quality is critical to minimizing Pb exposure.

Children drinking private well water have higher blood lead than those with city water

In the United States, 13% of households depend on an unregulated private well for their water. Compared with children in houses served by a regulated water utility, children in these homes have a 25% increased risk of elevated blood lead. Because lead is a neurotoxin, these children are at greater risk of experiencing irreversible cognitive damage, which can decrease their performance in school and increase their risks of behavioral problems. This study assesses associations between children’s blood lead and dependence on an unregulated private well for drinking water. It highlights the need for interventions to control lead corrosion from plumbing and well components (such as drop pipes, pump parts, and valves and fittings) in households depending on private wells.

Although the Flint, Michigan, water crisis renewed concerns about lead (Pb) in city drinking water, little attention has been paid to Pb in private wells, which provide drinking water for 13% of the US population. This study evaluates the risk of Pb exposure in children in households relying on private wells. It is based on a curated dataset of blood Pb records from 59,483 North Carolina children matched with household water source information. We analyze the dataset for statistical associations between children’s blood Pb and household drinking water source. The analysis shows that children in homes relying on private wells have 25% increased odds (95% CI 6.2 to 48%, P < 0.01) of elevated blood Pb, compared with children in houses served by a community water system that is regulated under the Safe Drinking Water Act. This increased Pb exposure is likely a result of corrosion of household plumbing and well components, because homes relying on private wells rarely treat their water to prevent corrosion. In contrast, corrosion control is required in regulated community water systems. These findings highlight the need for targeted outreach to prevent Pb exposure for the 42.5 million Americans depending on private wells for their drinking water.

Persistent Effects on Cardiorespiratory and Nervous Systems Induced by Long-Term Lead Exposure: Results from a Longitudinal Study

Long-term lead (Pb) exposure alters the normal development of the nervous system and physiology. It affects multiple organ systems, causing hypertension, cardiorespiratory dysfunction, being a well-known neurotoxin, inducing changes in neurogenesis, neurodegeneration, and glial cells. However, studies of the developmental effects of lead and its outcomes throughout life are lacking. Determine morphofunctional, behavioral, and cognitive developmental effects of long-term lead exposure at three different ages. Wistar rats were exposed to a Pb-acetate solution from fetal period until adulthood and compared to a non-exposed control group. General behavior and cognitive skills were evaluated by behavioral tests and physiological data and cardiorespiratory reflexes measured. Neurodegeneration, neuroinflammation, and synaptic activity were assessed by immunohistochemistry. Lead exposure caused long-lasting anxiety-like behavior and strong long-term memory impairment without changes in locomotor and exploratory activity. Hypertension was observed at all time points, concomitant with baroreflex impairment and increased chemoreflex sensitivity. Persistent neuroinflammation, transient synaptic overexcitation without neurodegeneration was observed. Long-term Pb exposure, since fetal period, causes long-lasting anxiety-like behavior, concomitant with hypertension, without general motor skills impairment. Synaptic overexcitation, reactive astrogliosis, and microgliosis could underlie behavioral and long-term memory changes, which might have been caused during developmental phases and consolidated during adulthood. Also, alterations observed in the cardiorespiratory reflexes can explain persistent hypertension. This longitudinal study identifies and characterizes lead toxicity nature and magnitude, important to devise and test potential interventions to attenuate the long-term harmful effects of lead on the nervous and cardiovascular systems.

Lead Exposure and Developmental Disabilities in Preschool-Aged Children

CONTEXT

Lead is a preventable environmental toxin that has been previously associated with deficits in cognition, academic performance, attention, and behavior in children. Very few studies, however, have examined the relationship between exposure to lead and documented developmental disabilities.

OBJECTIVE

This study examined the relative risk of lead exposure on developmental disabilities in preschool-aged children.

DESIGN

A statewide lead surveillance data set containing blood lead level (BLL) was integrated with another statewide data set containing developmental disability classifications for special education placement for preschool-aged children.

PARTICIPANTS

The participants were the 85 178 children (average age 2.6 years) whose records in both data sets were able to be linked. Forty-six percent of the participants had an identified developmental disability.

MAIN OUTCOME MEASURE

Developmental disability classification served as the main outcome measure.

RESULTS

A high BLL, defined as 5 μg/dL or more, was associated with significantly increased risk for developmental disabilities (risk ratio [RR] = 1.04; 95% CI = 1.01-1.08), particularly intellectual disability (RR = 1.58, 95% CI = 1.10-2.25) and developmental delay (DD; RR = 1.11, 95% CI = 1.06-1.17).

CONCLUSIONS

The results of this study are consistent with previous research identifying an association between lead exposure and numerous intellectual and educational outcomes and demonstrate that high BLL is associated with meeting eligibility criteria for developmental disabilities in young children. Continued research, surveillance, and prevention efforts are needed to further reduce the negative impacts of lead on individuals and society. Reducing or eliminating lead exposure would improve outcomes for individual children (eg, better academic performance) and reduce the burden to society (eg, lower enrollments in special education systems).

Systems Biology-Based Analysis Indicates Global Transcriptional Impairment in Lead-Treated Human Neural Progenitor Cells

Lead poisoning effects are wide and include nervous system impairment, peculiarly during development, leading to neural damage. Lead interaction with calcium and zinc-containing metalloproteins broadly affects cellular metabolism since these proteins are related to intracellular ion balance, activation of signaling transduction cascades, and gene expression regulation. In spite of lead being recognized as a neurotoxin, there are gaps in knowledge about the global effect of lead in modulating the transcription of entire cellular systems in neural cells. In order to investigate the effects of lead poisoning in a systemic perspective, we applied the transcriptogram methodology in an RNA-seq dataset of human embryonic-derived neural progenitor cells (ES-NP cells) treated with 30 µM lead acetate for 26 days. We observed early downregulation of several cellular systems involved with cell differentiation, such as cytoskeleton organization, RNA, and protein biosynthesis. The downregulated cellular systems presented big and tightly connected networks. For long treatment times (12 to 26 days), it was possible to observe a massive impairment in cell transcription profile. Taking the enriched terms together, we observed interference in all layers of gene expression regulation, from chromatin remodeling to vesicle transport. Considering that ES-NP cells are progenitor cells that can originate other neural cell types, our results suggest that lead-induced gene expression disturbance might impair cells’ ability to differentiate, therefore influencing ES-NP cells’ fate.

Early lead exposure and pubertal development in a Mexico City population

BACKGROUND

Previous studies have examined the association between blood lead levels and pubertal timing in adolescent girls; however, the evidence is lacking on the role of lead exposure during sensitive developmental periods on sexual maturation.

OBJECTIVES

To examine the association of prenatal and early childhood lead exposure with pubertal stages among 264 boys and 283 girls aged 9.8-18.0 years in Mexico City.

METHODS

We measured maternal bone lead (a proxy for cumulative fetal exposure to lead from maternal bone stores mobilized during pregnancy) at 1 month postpartum. Blood lead was measured annually from 1 to 4 years. Pubertal stage was assessed by a pediatrician. We examined the association between lead and pubertal stages of breast, pubic hair and genitalia using ordinal regression. Age at menarche was evaluated using Cox proportional-hazard models.

RESULTS

Multivariate models showed that maternal patella lead and early childhood blood lead were inversely associated with breast growth (patella OR = 0.72, 95% CI: 0.51-1.00; blood OR = 0.70, 95% CI: 0.53-0.93) in girls. Girls with maternal patella lead in the 3rd tertile and child blood lead in the 2nd tertile had a later age at menarche compared with girls in the 1st tertile (patella HR = 0.60, 95% CI: 0.41-0.88; blood HR = 0.65, 95% CI 0.46-0.91). Additionally, early childhood blood lead was negatively associated with pubic hair growth (OR = 0.68, 95% CI: 0.51-0.90) in girls. No associations were found in boys.

CONCLUSIONS

These data suggest that higher prenatal and early childhood exposure to lead may be associated with delayed pubertal development in girls but not boys. Our findings are consistent with previous analyses and reinforce the reproductive effects of lead for girls.

The role of soil mineralogy on oral bioaccessibility of lead: Implications for land use and risk assessment

Understanding the oral bioaccessibility of lead (Pb) present in soils in urbanized areas is important for the human exposure risk assessment. In particular, the role of the soil-mineralogy in the oral bioaccessibility has not been extensively studied. To investigate bioaccessibility, five types of periurban soils were collected, samples were spiked with the same amount of lead-chromates from traffic paint, and subjected to the in vitro Physiological Based Extraction Test (PBET). Ten samples of urban topsoils were collected at elementary schools playgrounds, Pb-bioaccessibility was measured, and a prediction equation for bioaccessibility was constructed. Mineralogy, and metal content were identified with a combination of X-ray powder diffraction, scanning electron microscopy, and portable X-ray fluorescence techniques. Traffic paint sample is made of 15% quartz (SiO₂), 13% crocoite (PbCrO₄), 55% calcite (CaCO₃), and 17% kaolinite (Al₂Si₂O₅(OH)₄) and it contains high metal content (Pb, Cr, Zn, and Ca). Studied soils are characterized by variable amounts of acid-neutralizing minerals (carbonates) and low metal content. Spiked soils contained almost equal concentration of Pb, Cr, and Zn, because the contribution of these metals is from the added paint. However, obtained Pb-bioaccessibility at gastric and intestinal conditions are variable (40 to 51% gastric, 24 to 70.5% intestinal). Carbonate content shows significant correlation (p < 0.05) with Cr, Ca, calcite, crocoite, and Pb-bioaccessible at gastric conditions. Correlation of Pb-bioaccessible at intestinal conditions is significant (p < 0.05) with kaolinite. Variability of Pb-bioaccesibility in urban environments is commonly associated to differences in Pb-sources, however, our results show that the bioaccessibility of the same pollutant behaves different for each soil type. This suggests that soil mineralogy may play a role in Pb-releasing at gastrointestinal conditions. Soil information about mineralogical characteristics from this study may help to reduce exposure to lead from urban sources if data are incorporated into urban planning.

XRF techniques to quantify heavy metals in vegetables at low detection limits

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Calibration routines for quantification of Pb in vegetables with XRF are optimized.

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These XRF methods achieved detection limits of 0.3 μg g⁻¹ for Pb in dry vegetables.

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Pb in raw vegetables is quantified at levels as low as 1 μg g⁻¹ with ED-XRF.

Sample preparation techniques, measurement routines and custom calibrations were developed and optimized for the quantification of Pb and additional heavy metals in dried and wet consumable vegetable tissues via WD-XRF and/or portable ED-XRF spectroscopy. After mitigating matrix influences fundamental to XRF quantification of heavy metals in a carbon matrix, the custom measurement and calibration routines were capable of detecting and quantifying Pb in dried prepared vegetable samples at concentrations relevant to the World Health Organization. The viability of each calibration was evaluated with measurements of vegetables grown in metals-rich garden soil collected from residential properties. Although robust calibrations for dried vegetables were obtained with WD-XRF, the slight compromise in the precision and accuracy of measurements with portable ED-XRF is offset by the portability of this technology. Heavy metal concentrations in wet coarsely-homogenized raw consumable vegetable tissues were quantified; however, further work is needed to test the viability of ED-XRF calibrations.

Intermittent low-level lead exposure provokes anxiety, hypertension, autonomic dysfunction and neuroinflammation

BACKGROUND

Exposures to lead (Pb) during developmental phases can alter the normal course of development, with lifelong health consequences. Permanent Pb exposure leads to behavioral changes, cognitive impairment, sympathoexcitation, tachycardia, hypertension and autonomic dysfunction. However, the effects of an intermittent lead exposure are not yet studied. This pattern of exposure has been recently increasing due to migrations, implementation of school exchange programs and/or residential changes.

OBJECTIVE

To determine and compare lead effects on mammal's behavior and physiology, using a rat model of intermittent and permanent Pb exposures.

METHODS

Fetuses were intermittently (PbI) or permanently (PbP) exposed to water containing lead acetate (0.2% w/v) throughout life until adulthood (28 weeks of age). A control group (CTL) without any exposure to lead was also used. Anxiety was assessed by elevated plus maze (EPM) and locomotor activity and exploration by open field test (OFT). Blood pressure (BP), electrocardiogram (ECG), heart rate (HR), respiratory frequency (RF), sympathetic and parasympathetic activity and baro- and chemoreceptor reflex profiles were evaluated. Immunohistochemistry protocol for the assessment of neuroinflammation, neuronal loss (NeuN), gliosis and synaptic alterations (Iba-1, GFAP, Syn), were performed at the hippocampus. One-way ANOVA with Tukey's multiple comparison between means were used (significance p < 0.05) for statistical analysis.

RESULTS

The intermittent lead exposure produced a significant increase in diastolic and mean BP values, concomitant with a tendency to sympathetic overactivity (estimated by increased low-frequency power) and without significant changes in systolic BP, HR and RF. A chemoreceptor hypersensitivity and a baroreflex impairment were also observed, however, less pronounced when compared to the permanent exposure. Regarding behavioral changes, both lead exposure profiles showed an anxiety-like behavior without changes in locomotor and exploratory activity. Increase in GFAP and Iba-1 positive cells, without changes in NeuN positive cells were found in both exposed groups. Syn staining suffered a significant decrease in PbI group and a significant increase in PbP group.

CONCLUSION

This study is the first to show that developmental Pb exposure since fetal period can cause lasting impairments in physiological parameters. The intermittent lead exposure causes adverse health effects, i.e, hypertension, increased respiratory frequency and chemoreflex sensitivity, baroreflex impairment, anxiety, decreased synaptic activity, neuroinflammation and reactive gliosis, in some ways similar to a permanent exposure, however some are lower-grade, due to the shorter duration of exposure. This study brings new insights on the environmental factors that influence autonomic and cardiovascular systems during development, which can help in creating public policy strategies to prevent and control the adverse effects of Pb toxicity.

Reduced Lead Exposure Following a Sensitization Program in Rural Family Homes Producing Traditional Mexican Ceramics

BACKGROUND

Traditional ceramics are a cultural heritage in Mexico, used by the general population in everyday life. These ceramics are glazed with lead oxide and are usually produced in households that share living and working spaces. Glazing is usually performed by women, and children are not restrained from the work space and frequently help, resulting in high levels of lead exposure for all. Interventions that promote a change in technology (such as lead-free glazes or efficient kilns) are often unrealistic for potters with fewer economic resources who depend on their production as their main income. Interventions focusing on exposure prevention (rather than a technology change) at the household level are scarce.

METHODS

Working hand-in-hand with a group of nine women, lay community workers, promotoras, from Santa Fe de Laguna, Michoacán, we developed a program focusing on the self-recognition of health risks. The program was composed of health education (including a lead in blood and bone measurement for women), health/work risk recognition and communication to the community, and work/living area reorganization and remediation in three stages: work with 1) promotoras, 2) their extended families, and 3) their community, including talks in elementary schools.

RESULTS

The promotoras developed and distributed risk communication graphic materials and delivered a lead-awareness talk in the Purhepecha language, in the local primary health-care clinic and three elementary schools. Lead in bone levels had a mean ± SD (min, max) of rotula: 84.8 μg/g ± 68.9 (23.89, 214.2), tibia 93.2 μg/g 81.2 (14.23, 261.21). We implemented safer and cleaner ceramic production in the promotoras workshops.Public Health Relevance: Environmental and occupational exposures can be reduced through programs that are tailored by and for a specific community. When there is no evident alternative technology for safer production, such programs can empower groups and lead to reduced exposure for their children, family and community.

Lead Exposure and Associated Risk Factors among New Migrant Children Arriving in Greece

Background: This study aims to assess lead exposure and associated risk factors among newly arrived migrant (M) (immigrant and refugees) children in Greece and a matched control of native (N) children. Methods: A prospective, cross-sectional study was performed in an outpatient clinic of a tertiary children’s hospital. Results: From 2010 to 2014, 598 children (M/N: 349/249) with a mean age of 6.96 years old (range 1–14, SD 3.76) were enrolled. Blood lead levels (BLLs) ranged from 0.7 to 21 μg/dL in migrant and from 0.4 to 10 μg/dL in native Greek children. Elevated BLLs ≥ 5 μg/dL were detected in 27.7% of migrants and 1.2% of natives (p < 0.001). A significant association was found between EBLLs and childrens’ age (≤5 years) (OR: 1.8, p-value 0.02) and EBLLs with Asian origin (OR: 3.63, p-value 0.023). Conclusion: New migrant children presented with increased BLLs when compared to their age- and sex-matched controls. Younger age and Asian origin were significant risk factors associated with elevated BLLs among children. Early screening, secondary prevention, and regular follow-up could prove useful in this vulnerable population.

Use of a Survey to Assess the Environmental Exposure and Family Perception to Lead in Children (<6 Years) in Four Valley Cities, Northwestern China

With the growth of industry, the extensive use of lead, and urban expansion in Northwestern Valley Cities (NVC) China, there is probable reason for presuming an increasing risk of lead exposure. However, little is known about the lead exposure of children less than 6 years old in NVC. As a first investigation, this study uses a survey to systematically determine the influences of various risk factors within the family environment, parents' background, children's behavior, mother's behavior during pregnancy, and parental perception about children's blood lead (CBL). A total of 596 families were recruited from the general population in Urumqi, Lanzhou, Xining and Yan'an. Parents, and their children (<6 years old), were asked about the environment and behaviors which could possibly relate with lead exposure. The results indicated that in the typical NVC of China, children's environment and behavior, parents' education level, and mother's pregnancy behavior, were associated with potential CBL. It was noted that not all parents in NVC China recognized the importance of children's lead exposure. Therefore, children's health care and medical screening campaigns need to be designed to improve family's fundamental knowledge of lead hazards, associated health effects, and prevention in the NVC of China.

Comparative metabolic profiling of vetiver (Chrysopogon zizanioides) and maize (Zea mays) under lead stress

Lead (Pb) contamination of residential soils in United States is attributed to use of Pb based paints prior to 1978 and their deterioration and accumulation in surface soils. Exposure to Pb due to ingestion and inhalation of Pb laden soil and dust causes neurological disorders, renal disorders, developmental and behavioral problems, particularly in children under the age of six. Vetiver grass is one of the leading choices for Pb remediation due to its ability to hyperaccumulate Pb, in addition to high biomass. In order to understand the effect of Pb on vetiver metabolic pathways, we compared the global metabolic changes in vetiver with that of maize, a Pb susceptible plant under Pb stress. Vetiver showed massive increase in levels of key metabolites in response to Pb, including amino acids, organic acids and coenzymes. Maize showed very modest increase in some of the same metabolites, and no change in others. The results provide the first indication of the difference in metabolic response of the hyperaccumulator, vetiver to lead stress as compared to maize.

The Flint Food Store Survey: combining spatial analysis with a modified Nutrition Environment Measures Survey in Stores (NEMS-S) to measure the community and consumer nutrition environments

OBJECTIVE

The goal of the present study was to use a methodology that accurately and reliably describes the availability, price and quality of healthy foods at both the store and community levels using the Nutrition Environment Measures Survey in Stores (NEMS-S), to propose a spatial methodology for integrating these store and community data into measures for defining objective food access.

SETTING

Two hundred and sixty-five retail food stores in and within 2 miles (3·2 km) of Flint, Michigan, USA, were mapped using ArcGIS mapping software.

DESIGN

A survey based on the validated NEMS-S was conducted at each retail food store. Scores were assigned to each store based on a modified version of the NEMS-S scoring system and linked to the mapped locations of stores. Neighbourhood characteristics (race and socio-economic distress) were appended to each store. Finally, spatial and kernel density analyses were run on the mapped store scores to obtain healthy food density metrics.

RESULTS

Regression analyses revealed that neighbourhoods with higher socio-economic distress had significantly lower dairy sub-scores compared with their lower-distress counterparts (β coefficient=-1·3; P=0·04). Additionally, supermarkets were present only in neighbourhoods with <60 % African-American population and low socio-economic distress. Two areas in Flint had an overall NEMS-S score of 0.

CONCLUSIONS

By identifying areas with poor access to healthy foods via a validated metric, this research can be used help local government and organizations target interventions to high-need areas. Furthermore, the methodology used for the survey and the mapping exercise can be replicated in other cities to provide comparable results.

"What do you know?"--knowledge among village doctors of lead poisoning in children in rural China

BACKGROUND

This study evaluates the extent of village doctors' knowledge of lead poisoning in children in rural China and assesses the characteristics associated with possessing accurate knowledge.

METHODS

A cross-sectional, questionnaire-based survey of 297 village doctors in Fenghuang County, Hunan Province, China was conducted. All village doctors were interviewed face-to-face using a "What do you know" test questionnaire focusing on prevention strategies and lead sources in rural children.

RESULTS

A total of 287 (96.6%) village doctors completed the survey in full. Most village doctors had an appropriate degree of general knowledge of lead poisoning; however, they had relatively poor knowledge of lead sources and prevention measures. Village doctors with an undergraduate level education scored an average of 2.7 points higher than those who had a junior college level education (p = 0.033). Village doctors with an annual income ≤ 10,000 RMB yuan scored 1.03 points lower than those whose income was >10,001 RMB yuan. Ethnic Han village doctors scored 1.12 points higher, on average, than ethnic Tujia village doctors (p = 0.027).

CONCLUSIONS

This study identified important gaps in knowledge concerning lead poisoning in children among a rural population of village doctors. There is a clear need for multifaceted interventions that target village doctors to improve their knowledge regarding lead poisoning in children. The "What do you know" questionnaire is a new tool to evaluate lead poisoning knowledge and education projects.

A mechanism underlies fish GRP78 protection against Pb2+ toxicity

Heavy metal exposure impacts basic cellular processes and results in serious toxicological effects. Pb²⁺ can activate the response to endoplasmic reticulum (ER) stress by protein denaturation, changing intracellular calcium homeostasis, and inducing cell death. As an ER retention protein, 78-kDa glucose-regulated protein (GRP78) can relieve the Pb²⁺-induced ER stress and enhance cell viability. We previously showed that heavy metal ions such as Pb²⁺ etc. are harmful to fish cell lines in a time- and dose-dependent manner. The phenomenon is accompanied by the increasing accumulation of grass carp GRP78 (CiGRP78), which can protect the cells from heavy metal ion cytotoxicity. Here, we investigated the mechanism in which CiGRP78 exerted its protective function. Using metal ions affinity elution method and fluorescent spectral analysis, we showed that CiGRP78 could respectively form a complex with Calcium, Lead and Cadmium ions, especially with Lead ion in vitro. However, another ER retention protein CiGRP94 could not bind to Pb²⁺, highlighting the functional differentiation might exist in CiGRP78 and CiGRP94 in regulating heavy metal cytotoxicity. Our results suggested that CiGRP78 might increase cellular tolerance to Pb²⁺ via the direct interaction with it.

Association of blood heavy metals with developmental delays and health status in children

The aim of this study was to evaluate the association of blood lead, mercury, and cadmium concentrations with developmental delays and to explore the association of these concentrations with the health status of children. This study recruited 89 children with developmental delays and 89 age- and sex-matched children with typical development. Their health status was evaluated using the Pediatric Quality of Life (PedsQL) Inventory for health-related quality of life (HRQOL) and the Pediatric Outcomes Data Collection Instrument for function. Family function was also evaluated. Blood lead, mercury, and cadmium concentrations were measured using inductively coupled mass spectrometry. The children with developmental delays had a considerably poorer HRQOL, lower functional performance and family function, and a higher blood lead concentration than those with typical development. The blood lead concentration had a significantly positive association with developmental delays [odds ratio (OR) = 1.54, p < 0.01] in a dose-response manner, and it negatively correlated with PedsQL scores (regression coefficient: −0. 47 to −0.53, p < 0.05) in all the children studied. The higher blood cadmium concentration showed a significantly positive association with developmental delays (OR = 2.24, for >1.0 μg/L vs. <0.6 μg/L, p < 0.05). The blood mercury concentration was not associated with developmental delays and health status.

Seasons and neighborhoods of high lead toxicity in New York City: The feral pigeon as a bioindicator

Human-induced rapid environmental change has created a global pandemic of neurobehavioral disorders in which industrial compounds like lead are the root cause. We assessed the feral pigeon (Columba livia) as a lead bioindicator in New York City. We collected blood lead level records from 825 visibly ill or abnormally behaving pigeons from various NYC neighborhoods between 2010 and 2015. We found that blood lead levels were significantly higher during the summer, an effect reported in children. Pigeon blood lead levels were not significantly different between years or among neighborhoods. However, blood lead levels per neighborhood in Manhattan were positively correlated with mean rates of lead in children identified by the NYC Department of Health and Mental Hygiene as having elevated blood lead levels (>10 μg/dl). We provide support for the use of the feral pigeon as a bioindicator of environmental lead contamination for the first time in the U.S. and for the first time anywhere in association with rates of elevated blood lead levels in children. This information has the potential to enable measures to assess, strategize, and potentially circumvent the negative impacts of lead and other environmental contaminants on human and wildlife communities.

Project TENDR: Targeting Environmental Neuro-Developmental Risks The TENDR Consensus Statement

Summary: Children in America today are at an unacceptably high risk of developing neurodevelopmental disorders that affect the brain and nervous system including autism, attention deficit hyperactivity disorder, intellectual disabilities, and other learning and behavioral disabilities. These are complex disorders with multiple causes—genetic, social, and environmental. The contribution of toxic chemicals to these disorders can be prevented. Approach: Leading scientific and medical experts, along with children’s health advocates, came together in 2015 under the auspices of Project TENDR: Targeting Environmental Neuro-Developmental Risks to issue a call to action to reduce widespread exposures to chemicals that interfere with fetal and children’s brain development. Based on the available scientific evidence, the TENDR authors have identified prime examples of toxic chemicals and pollutants that increase children’s risks for neurodevelopmental disorders. These include chemicals that are used extensively in consumer products and that have become widespread in the environment. Some are chemicals to which children and pregnant women are regularly exposed, and they are detected in the bodies of virtually all Americans in national surveys conducted by the U.S. Centers for Disease Control and Prevention. The vast majority of chemicals in industrial and consumer products undergo almost no testing for developmental neurotoxicity or other health effects. Conclusion: Based on these findings, we assert that the current system in the United States for evaluating scientific evidence and making health-based decisions about environmental chemicals is fundamentally broken. To help reduce the unacceptably high prevalence of neurodevelopmental disorders in our children, we must eliminate or significantly reduce exposures to chemicals that contribute to these conditions. We must adopt a new framework for assessing chemicals that have the potential to disrupt brain development and prevent the use of those that may pose a risk. This consensus statement lays the foundation for developing recommendations to monitor, assess, and reduce exposures to neurotoxic chemicals. These measures are urgently needed if we are to protect healthy brain development so that current and future generations can reach their fullest potential.

Lead in candy consumed and blood lead levels of children living in Mexico City

BACKGROUND

Recent studies have shown that lead exposure continues to pose a health risk in Mexico. Children are a vulnerable population for lead effects and Mexican candy has been found to be a source of exposure in children. There are no previous studies that estimates lead concentrations in candy that children living in Mexico City consume and its association with their blood lead level.

OBJECTIVES

To evaluate whether there is an association between reported recent consumption of candies identified to have lead, and blood lead levels among children in Mexico City.

METHODS

A subsample of 171 children ages 2-6 years old, from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study was assessed between June 2006 and July 2007. The candy reported most frequently were analyzed for lead using ICP-MS. The total weekly intake of lead through the consumption of candy in the previous week was calculated. Capillary blood lead levels (BLL) were measured using LeadCare (anodic stripping voltammetry).

RESULTS

Lead concentrations ≥0.1ppm, the FDA permitted level (range: 0.13-0.7ppm) were found in 6 samples out of 138 samples from 44 different brands of candy. Median BLL in children was 4.5µg/dl. After adjusting for child's sex, age, BMI, maternal education & occupation, milk consumption, sucking the candy wrapper, use of lead-glazed pottery, child exposure behavior, living near a lead exposure site and use of folk remedies, an increase of 1µg of lead ingested through candy per week was associated with 3% change (95% CI: 0.1%, 5.2%) in BLL.

CONCLUSIONS

Although lead concentrations in candy were mostly below the FDA permitted level, high lead concentrations were detected in 4% of the candy samples and 12% of brands analyzed. Although candy intake was modestly associated with children's BLL, lead should not be found in consumer products, especially in candy that children can consume due to the well documented long-lasting effect of lead exposure.

Prenatal chemical exposures and child language development

The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals, both manmade (insulating materials, flame retardants, pesticides) and naturally occurring (e.g., lead, mercury), may be associated with delays or impairments in language development. We focus primarily on a subset of more extensively studied chemicals-polychlorinated biphenyls (PCBs), lead, and methyl mercury-for which a reasonable body of literature on neurodevelopmental outcomes is available. We also briefly summarize the smaller body of evidence for other chemicals including polybrominated diphenyl ether flame retardants (PBDEs) and organophosphate pesticides. Very few studies have used specific assessments of language development and function. Therefore, we included discussion of aspects of cognitive development such as overall intellectual functioning and verbal abilities that rely on language, as well as aspects of cognition such as verbal and auditory working memory that are critical underpinnings of language development. A high percentage of prospective birth cohort studies of PCBs, lead, and mercury have reported exposure-related reductions in overall IQ and/or verbal IQ that persist into middle or late childhood. Given these findings, it is important that clinicians and researchers in communication sciences and disorders are aware of the potential for environmental chemicals to impact language development.

LEARNING OUTCOMES

The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals may be associated with delays or impairments in language development. Readers will gain an understanding of the literature suggesting that early exposure to polychlorinated biphenyls (PCBs), lead, and mercury may be associated with decrements in cognitive domains that depend on language or are critical for language development. We also briefly summarize the smaller body of evidence regarding polybrominated diphenyl ether flame retardants (PBDEs) and organophosphate pesticides. Very few studies of exposure to these chemicals have used specific assessments of language development; thus, further investigation is needed before changes in clinical practice can be suggested.

Blood lead levels in children aged 0-6 years old in Hunan Province, China from 2009-2013

Objectives

The aim of this study is to describe blood lead levels (BLLs) and the prevalence of elevated blood lead levels (EBLLs) in children aged 0–6 years old and to analyze the BLL trend in children from 2009 to 2013 in China.

Methods

A total of 124,376 children aged 0–6 years old were recruited for this study from January 1^st 2009 to December 31^st 2013. Their blood lead levels were analyzed using atomic absorption spectrometry.

Results

The median BLL was 64.3 μg/L (IQR: 49.6–81.0), and the range was 4.3–799.0 μg/L. Blood lead levels were significantly higher in boys (66.0 μg/L) than in girls (61.9 μg/L) (P<0.001). The overall prevalence of BLLs≥100 μg/L was 10.54% in children aged 0–6 years in Hunan Province. Between 2009 and 2013, the prevalence of EBLLs (≥100 μg/L) decreased from 18.31% to 4.26% in children aged 0–6 years and increased with age. The prevalence of EBLLs has dramatically decreased in two stages (2009–2010 and 2012–2013), with a slight fluctuation in 2010 and 2011.

Conclusions

Both BLLs and the prevalence of EBLLs in children aged 0–6 years old declined substantially from 2009 to 2013 in Hunan Province; however, both remain at unacceptably high levels compared to developed countries. Comprehensive strategies are required to further reduce blood lead levels in children.

Pediatric Integrative Medicine Approaches to Attention Deficit Hyperactivity Disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) is the most common neuropsychiatric disorder in children and is increasing in prevalence. There has also been a related increase in prescribing stimulant medication despite some controversy whether ADHD medication makes a lasting difference in school performance or achievement. Families who are apprehensive about side effects and with concerns for efficacy of medication pursue integrative medicine as an alternative or adjunct to pharmacologic and cognitive behavioral treatment approaches. Integrative medicine incorporates evidence-based medicine, both conventional and complementary and alternative therapies, to deliver personalized care to the patient, emphasizing diet, nutrients, gut health, and environmental influences as a means to decrease symptoms associated with chronic disorders. Pediatric integrative medicine practitioners are increasing in number throughout the United States because of improvement in patient health outcomes. However, limited funding and poor research design interfere with generalizable treatment approaches utilizing integrative medicine. The use of research designs originally intended for drugs and procedures are not suitable for many integrative medicine approaches. This article serves to highlight integrative medicine approaches in use today for children with ADHD, including dietary therapies, nutritional supplements, environmental hygiene, and neurofeedback.