Lead

A comprehensive analysis of children's blood lead levels in Latin America and the Caribbean over the last eight years: Progress and recommendations

In 2017 we published a review on blood lead levels (BLL) in children from Latin America and the Caribbean (LAC) for data available up to 14th of March 2014 and recommended the identification and control of "lead hot spots". In the present study, an evaluation of progress toward reducing BLL in the region was carried out. A systematic review of the latest literature on lead exposure in the LAC region held on the PubMed, Web of Science and LILACS databases (January 2014 to March 2022) was conducted using the PRISMA methodology. Only original papers published in peer-reviewed English, Spanish, or Portuguese journals were eligible. A total of 558 papers were retrieved, 77 of which met the selection criteria and 31 (40.25 %) were carried out in Mexico. The prevalence of children with BLL above 10 μg. dL-1 was 22.08 % in the previous review versus 6.78 % in the current study. In the present review, the prevalence of children with BLL above 5 μg. dL-1 was 29.62 %, and only one study reported a BLL prevalence rate between 3.3 and 5 μg. dL-1. The highest BLLs were associated with well-known sources or occupational exposures. The number of countries (n = 13) that published data on BLL in children was lower compared to the previous review (n = 16). Most studies were conducted in areas with known lead exposure sources, similar to the earlier review. The percentage of children at risk of lead poisoning in the region remains unknown because few studies have published data on environmental exposure levels and most samples were relatively small. The recommendation to identify and control sources of lead exposure was maintained, while further suggestions for establishing a systematic public health surveillance system for lead were proposed to help reduce the knowledge gap and inform public health policy-making in LAC.

Lead exerts a depression of neurotransmitter release through a blockade of voltage dependent calcium channels in chromaffin cells

The present work, using chromaffin cells of bovine adrenal medullae (BCCs), aims to describe what type of ionic current alterations induced by lead (Pb2+) underlies its effects reported on synaptic transmission. We observed that the acute application of Pb2+ lead to a drastic depression of neurotransmitters release in a concentration-dependent manner when the cells were stimulated with both K+ or acetylcholine, with an IC50 of 119,57 μM and of 5,19 μM, respectively. This effect was fully recovered after washout. Pb2+ also blocked calcium channels of BCCs in a time- and concentration-dependent manner with an IC50 of 6,87 μM. This blockade was partially reversed upon washout. This compound inhibited the calcium current at all test potentials and shows a shift of the I-V curve to more negative values of about 8 mV. The sodium current was not blocked by acute application of high Pb2+ concentrations. Voltage-dependent potassium current was also shortly affected by high Pb2+. Nevertheless, the calcium- and voltage-dependent potassium current was drastically depressed in a dose-dependent manner, with an IC50 of 24,49 μM. This blockade was related to the prevention of Ca2+ influx through voltage-dependent calcium channels coupled to Ca2+-activated K+-channels (BK) instead a direct linking to these channels. Under current-clamp conditions, BCCs exhibit a resting potential of -52.7 mV, firing spontaneous APs (1-2 spikes/s) generated by the opening of Na+ and Ca2+-channels, and terminated by the activation of K+ channels. In spite of the effect on ionic channels exerted by Pb2+, we found that Pb2+ didn't alter cellular excitability, no modification of the membrane potential, and no effect on action potential firing. Taken together, these results point to a neurotoxic action evoked by Pb2+ that is associated with changes in neurotransmitter release by blocking the ionic currents responsible for the calcium influx.

Toxicity and bioremediation of the lead: a critical review

Lead is a naturally occurring, bluish-gray metal that is found in small quantities in the earth's crust. The existing literature demonstrates that non-biodegradable character and continuous use results in accumulation of lead concentration in the environment and causes various ill effects such as neurotoxicity, change in psychological and behavioral development of different organisms. Nowadays the most effective technique in the revival of the environment is bioremediation and it is environmentally friendly and cost-effective. Bacterial strains such as Oceanobacillus profundus and Lactobacillus acidophilus ATCC4356 have the ability to reduce lead 97% and 73.9%, respectively. Similarly some species of algae and fungal strains also showed lead removal efficiency as 74% (spirulina), 97.1% (Chlorella kessleri), 95.5% (Penicillium janthinillum) and 86% (Aspergillus flavus). Biodegradation of lead by various microbes would be the most efficient and sustainable approach. This review focuses on toxicity, fate of lead in the environment and its microbial degradation.

Effectiveness of educational interventions for the prevention of lead poisoning in children: a systematic review

INTRODUCTION

Childhood exposure to lead has severe health consequences including long-term physical, behavioral, and learning problems. Lead poisoning often occurs in the home and persists as a form of environmental injustice, disparately impacting certain children based on factors such as socioeconomic status, immigration status, and race. Because abatement is costly, many prevention programs rely on educational interventions. We conducted a systematic review to assess the effectiveness of educational interventions on reducing blood lead levels (BLL) in children.

CONTENT

Following PRISMA-P guidelines, a librarian-guided search strategy incorporated database-specific subject headings and keywords related to lead poisoning and education, and encompassed four databases: Ovid MEDLINE, Scopus, Web of Science Core Collection and CINAHL. Two reviewers screened the results for those that met inclusion criteria (original research, study population of children under 18 years, inclusion of an educational intervention, outcome of BLL).

SUMMARY AND OUTLOOK

We screened the titles of 2,062 non-duplicate studies, the abstracts of 78 studies, and full texts of 23 articles, resulting in 17 articles that met eligibility criteria. Thirteen studies used multi-pronged interventions, which precluded comprehensive assessment of the effectiveness of the educational component. Interventions that had success in lowering BLL included some notable elements: longevity of intervention, consideration of culture and ethnicity; use of a community or home-based approach; and provision of supplies or assistance with cleaning. Of the four of studies that used solely educational interventions, three were successful in reducing BLL. Among the 12 studies that used a control group, six found their interventions to be successful in reducing BLL. This review found that educational interventions, either alone or as part of a multi-pronged approach, do not consistently reduce BLL in children. However, educational interventions may decrease severity of lead poisoning in children when more robust interventions are not feasible.

Animal Models of Childhood Exposure to Lead or Manganese: Evidence for Impaired Attention, Impulse Control, and Affect Regulation and Assessment of Potential Therapies

Behavioral disorders involving attention and impulse control dysfunction, such as ADHD, are among the most prevalent disorders in children and adolescents, with significant impact on their lives. The etiology of these disorders is not well understood, but is recognized to be multifactorial, with studies reporting associations with polygenic and environmental risk factors, including toxicant exposure. Environmental epidemiological studies, while good at establishing associations with a variety of environmental and genetic risk factors, cannot establish causality. Animal models of behavioral disorders, when properly designed, can play an essential role in establishing causal relationships between environmental risk factors and a disorder, as well as provide model systems for elucidating underlying neural mechanisms and testing therapies. Here, we review how animal model studies of developmental lead or manganese exposure have been pivotal in (1) establishing a causal relationship between developmental exposure and lasting dysfunction in the domains of attention, impulse control, and affect regulation, and (2) testing the efficacy of specific therapeutic approaches for alleviating the lasting deficits. The lead and manganese case studies illustrate how animal models can advance knowledge in ways that are not possible in human studies. For example, in contrast to the Treatment of Lead Poisoned Children (TLC) human clinical trial evaluating succimer chelation efficacy to improve cognitive functioning in lead-exposed children, our developmental lead exposure animal model showed that succimer chelation can produce lasting cognitive benefits if chelation sufficiently reduces brain lead levels. In addition, this study revealed that succimer treatment in the absence of lead exposure produces lasting cognitive dysfunction, highlighting potential risks of chelation in off-label uses, such as the treatment of autistic children without a history of lead exposure. Our animal model of developmental manganese exposure has demonstrated that manganese can cause lasting attentional and sensorimotor deficits, akin to an ADHD-inattentive behavioral phenotype, thereby providing insights into the role of environmental exposures as contributors to ADHD. These studies have also shown that oral methylphenidate (Ritalin) can fully alleviate the deficits produced by early developmental Mn exposure. Future work should continue to focus on the development and use of animal models that appropriately recapitulate the complex behavioral phenotypes of behavioral disorders, in order to determine the mechanistic basis for the behavioral deficits caused by developmental exposure to environmental toxicants, and the efficacy of existing and emerging therapies.

Blood Lead Level and Handgrip Strength in Preadolescent Polish Schoolchildren

Environmental pollutions, particularly toxic elements such as lead, are among the most significant factors affecting the growth and functional development of children. The aim of this study was to evaluate the effect of blood lead levels on handgrip strength (HGS) in urban children resident in the Copper Basin of Lower Silesia, Poland, controlling for the effects of chronological age, body size and socioeconomic status. The study included 165 boys (9−11 years of age) and 79 girls (9−10 years of age) from Polkowice town. Anthropometric measurements involved height, body mass and grip strength of the left and right hands. Maternal education was a proxy for socioeconomic status. Based on the median value of blood lead level (3.10 µg/dL), the two groups-below and above/equal median value-were defined. Analysis of covariance revealed that age (all p < 0.001), sex (at least p < 0.01), BMI (all p < 0.001), and blood lead level (at least p < 0.05) had a significant effect on the three indicators of HGS (right hand, left hand, average), while the level of maternal education did not significantly affect HGS (p > 0.05). The results of this study indicate a potentially negative effect of elevated blood lead level on grip strength in preadolescent children, irrespective of sex.

Hyaluronic Acid Methacrylate Hydrogel-Modified Electrochemical Device for Adsorptive Removal of Lead(II)

This paper presents the development of a compact, three-electrode electrochemical device functionalized by a biocompatible layer of hyaluronic acid methacrylate (HAMA) hydrogel for the adsorptive removal of detrimental lead (Pb(II)) ions in aqueous solutions. An adsorption mechanism pertaining to the observed analytical performance of the device is proposed and further experimentally corroborated. It is demonstrated that both the molecular interactions originating from the HAMA hydrogel and electrochemical accumulation originating from the electrode beneath contribute to the adsorption capability of the device. Infrared spectral analysis reveals that the molecular interaction is mainly induced by the amide functional group of the HAMA hydrogel, which is capable of forming the Pb(II)–amide complex. In addition, inductively coupled plasma mass spectrometric (ICP-MS) analysis indicates that the electrochemical accumulation is particularly valuable in facilitating the adsorption rate of the device by maintaining a high ion-concentration gradient between the solution and the hydrogel layer. ICP-MS measurements show that 94.08% of Pb(II) ions present in the test solution can be adsorbed by the device within 30 min. The HAMA hydrogel-modified electrochemical devices exhibit reproducible performance in the aspect of Pb(II) removal from tap water, with a relative standard deviation (RSD) of 1.28% (for n = 8). The experimental results suggest that the HAMA hydrogel-modified electrochemical device can potentially be used for the rapid, on-field remediation of Pb(II) contamination.

Geophagia: Benefits and potential toxicity to human—A review

Geophagy is the habit of consuming clay soil such as chalk or kaolin. Though it is globally practiced, the safety of those involved is yet to be fully established. It is thought to be highly prevalent in pregnant women because of its antinausea or therapeutic effects. This practice is also thought to be provoked by some nutritional needs, but in modern society its etiology is obscure. The mineralogical and chemical compositions of clay may vary from one region to another and even in all form of rocks clay constitutes. Published articles in geophagy indicate lack of adequate investigations into the toxicity of geophagy, though it is globally practiced and more prevalent in Africa (as a continent) or in Africans migrants. Some studies have helped to identify some minerals that are toxic to human if ingested. In most cases, the potential toxicity emphasized by these studies is based on the detection of the presence of these nuisance elements in the geophagic materials. Scientifically, a lot has been done in the light of detection of toxic matter, but more investigations on metabolic studies are still necessary. The variability of clay content with respect to source motivated this review on geophagy and its potential toxicity to human. This review is aimed at bringing out findings that would enable a better understanding of the toxicity potential of geophagy across context and taxa.

Environmental lead exposure and its correlation with intelligence quotient level in children

BACKGROUND

Lead (Pb) is ubiquitous, naturally occurring heavy metal that has a neurotoxic effect on the CNS and causes a range of health problems in humans, including cognitive impairment. Its toxicity remains a worldwide health issue, especially in developing countries. In this study, we tend to investigate the relationship between Pb poisoning and sociodemographic status, intellectual and neurobehavioral capabilities of children.

METHODS

The background characteristics of the research subjects were collected via questionnaire. The study involved 43 children, aged from 4 to 12 years. Blood lead (BL) levels were analysed by using anodic stripping voltammeter (ASV). Intelligence quotient (IQ) was another parameter that was assessed via using the Goodenough draw-A-person test in Pb exposed as well as control children. Although sociodemographic information was obtained in a questionnaire pattern from the parents.

RESULTS

The mean of BL level was 19.93 ± 9.22 μg/dL. BL levels were considerably higher with low social status (p < 0.05), maternal employment (p < 0.001) and the maximum time spent outdoors (p < 0.001). Source of water, age of subjects, type of house and kohl used by children was observed to be significantly correlated with BL levels i.e. (p < 0.05). IQ levels were decreased in a concentration dependent manner (p < 0.01). Negative correlations were found between BL levels and IQ levels (r = -0.963, <0.01). Girls were found to be higher IQ level than boys (p < 0.05). Moreover, higher socioeconomic status had a higher IQ level (p < 0.01) as compared to low.

CONCLUSION

BL levels were significantly associated with IQ levels. Sociodemographic characteristic was also found to be one of the risk factors that influenced the BL levels of children. Our investigations have demonstrated that the exposure of Pb severely affected the learning with memory, and the intelligence quotient of children, that is found inversely proportional in respect to BL levels.

Study of controlled migration of cadmium and lead into foods from plastic utensils for children

Lead (Pb) is a highly neurotoxic chemical element known for reducing intelligence quotient (IQ) and promoting antisocial behavior in children and adolescents, while cadmium (Cd) is a carcinogenic bioaccumulative element. Both these metals are included in the priority pollutant list of the United States Environmental Protection Agency and in the WHO List of Chemicals of Major Public Health Concern, where contaminated foods and beverages are the most common pathways of exposure. The objective of this study was to determine total Cd and Pb levels in colored plastic utensils (cups, mugs, bowls, feeding bottles, and plates) for use by children and to measure the specific migration of these elements into beverages and foods. Total contaminant levels were determined using a handheld X-ray fluorescence analyzer. Specific migration tests were conducted using the simulant solutions acetic acid 3% (m/v) and water. Migration levels were determined by ICP-MS. Specific migration tests for Pb were also performed on commercially available samples (cola soft drink, orange juice, vinegar, and milk), with levels determined by graphite-furnace atomic absorption spectrometry (GF-AAS). A total of 674 utensils were analyzed in loco at major commercial centers in Greater São Paulo, of which 87 were purchased for containing Cd and Pb concentrations above permitted limits. Mean concentrations of the metals detected in the purchased utensils were 1110 ppm for Pb and 338 ppm for Cd. For specific migration assays, Pb levels were 187, 13, and 380 times above the permitted limit (0.01 mg.kg -1) for acetic acid, water, and orange juice, respectively. Cd levels were 50 and 2.4 times above the maximum permitted limit (0.005 mg.kg -1) for acetic acid and water, respectively. The districts where the utensils were purchased were grouped according to their social vulnerability index and compared using ANOVA. Pb levels were different between low and medium/high social vulnerability groups (p = 0.006). The findings corroborate the initial hypothesis that these utensils constitute a major source of exposure to PTEs such as Cd and Pb, pointing to the need for stricter regulation and inspection by the Brazilian regulatory agencies.

The role of dietary factors on blood lead concentration in children and adolescents - Results from the nationally representative German Environmental Survey 2014-2017 (GerES V)

In industrialized nations, human lead exposure has decreased significantly in recent decades. Nevertheless, due to its toxic effects, this heavy metal remains a public health concern with children and adolescents being particularly at risk. In Europe nowadays, oral intake via food and drinking water is the predominant exposure pathway for lead. The objective of the present study was to investigate the association between dietary factors and blood lead (PbB) level of 3- to 17-year-old children and adolescents living in Germany, using data from the fifth German Environmental Health Survey (GerES V) and the Child and Adolescent Health Survey (KiGGS Wave 2). GerES V and KiGGS Wave 2 are two national population-representative studies conducted between 2014 and 2017, including measurement of lead concentrations in blood from 720 children and adolescents aged 3-17 years (mean age = 10.21, SD age = 4.36). Using multiple linear regression, sociodemographic and environmental characteristics as well as dietary factors could be identified as significant exposure determinants of PbB concentrations. Lead intake via domestic tap water was the strongest predictor of elevated PbB levels with 27.6% (p-value< .001) higher concentrations of highest compared to none lead intake via tap water. Other foods which were found to be relevant to PbB levels were meat, fruit, and fruit juice. While meat or fruit consumption were each associated with about 13% (p-value < .05) lower PbB levels, fruit juice drinking was associated with up to 12.2% (p-value = .04) higher PbB levels. In conclusion, results indicate the importance of dietary habits for lead exposure in children and adolescents. To protect vulnerable groups, it is recommended that future research and lead-reducing measures pay more attention to dietary links.

[Blood and faecal lead levels in children with various functional gastrointestinal disorders]

INTRODUCTION

To investigate the blood lead levels (BLLs) and faecal lead levels (FLLs) in children with various functional gastrointestinal disorders (FGIDs) and compare them with controls.

PATIENTS AND METHODS

One hundred and 2children with FGIDs defined by the Rome IV criteria, aged 4 -18 years, and one hundred and 2sex matched healthy children were enrolled in the study. Children with FGIDs were divided into 3subgroups as functional constipation (FC) (n=36), functional abdominal pain (FAP) (n=36) and functional náusea (FN) (n=30). The lead levels were measured using atomic absorption spectrometer.

RESULTS

The median BLLs in the FGIDs group was significantly higher than in controls (5.12 and 1.77μg/dL, respectively). The BLLs were above 5μg/dL in 51,9% of children with FGIDs. There was statistically significant difference in BLLs between FC subgroup and the other subgroups (FAP and FN) (P=.003, P<.001 respectively). The FLLs in the FGIDs group was significantly higher than in controls (28.08 and 0.01μg/g, respectively). There was no significant difference in FLLs between FC subgroup and the other subgroups (P=.992, P=.989 respectively). No significant relation found between BLLs and FLLs of the FGIDs group (P =.123).

CONCLUSION

This study revealed that children with FGIDs had higher BLLs and FLLs than controls and also more than half of children with FGIDs had BLLs ≥5μg/dL which is toxic level. These results might revive the question of whether or not clinician need to evaluate routine BLLs in children with FGIDs.

Assessment of Thyroid Function and Oxidative Stress State in Foundry Workers Exposed to Lead

BACKGROUND

Exposure to lead (Pb) has been associated with endocrine, hematological, gastrointestinal, renal and neurological problems in humans. However, effects on the thyroid gland are controversial.

OBJECTIVES

The aim of the present study was to assess thyroid function in foundry workers occupationally exposed to Pb and the mechanism of oxidative-antioxidant imbalance.

METHODS

Thyroid function parameters and markers of oxidative stress were examined in 59 adult males who had been occupationally exposed to Pb. The results were then compared to those of 28 male subjects who had no history of Pb exposure or thyroid abnormalities and served as a control group.

RESULTS

Mean blood lead levels (16.5±1.74 μg/dl) were significantly higher among the exposed workers compared to those of the control group (12.8±1.16 μg/dl, (p <0.001)). The exposed group had significantly increased free triiodothyronine (FT3), free thyroxine (FT4) and significantly decreased thyroid stimulating hormone (TSH) (1.77±0.44 μIU/ml), whereas the control group had a TSH level of 2.61±0.94 μIU/ml (p< 0.0001). A state of oxidative stress was indicated by the significant increase in mean levels of malondialdehyde (MDA) and significant decrease in glutathione (GSH) (p < 0.0001). There was a significant positive correlation (r=0.358, p <0.05) between blood lead levels (BLL) and duration of employment, while BLL showed a significant negative correlation with TSH (r =-0.486, p <0.001), and GSH (r =-0.336, p <0.05). Of the occupationally exposed workers, 32.76% had elevated thyroid hormones. The results showed a significant positive relationship between GSH and TSH (β coefficient=0.274, p < 0.05), MDA with FT3 (β coefficient=0.355, p < 0.05) and FT4 (β coefficient = 0.491, p < 0.0001) among exposed workers.

CONCLUSIONS

Workers exposed to Pb dust proved to be at risk for hyperthyroidism, which was found to have a significant role in oxidative-antioxidant imbalance present among workers with increasing duration of exposure.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

This study was approved by the Ethical Committee of the National Research Centre in Egypt (NRC) under the registration number 15225.

COMPETING INTERESTS

The authors declare no competing financial interests.

Current trends of blood lead levels, distribution patterns and exposure variations among household members in Kabwe, Zambia

Childhood lead (Pb) poisoning has devastating effects on neurodevelopment and causes overt clinical signs including convulsions and coma. Health effects including hypertension and various reproductive problems have been reported in adults. Historical Pb mining in Zambia's Kabwe town left a legacy of environmental pollution and childhood Pb poisoning. The current study aimed at establishing the extent of Pb poisoning and exposure differences among family members in Kabwe as well as determining populations at risk and identify children eligible for chelation therapy. Blood samples were collected in July and August 2017 from 1190 household members and Pb was measured using a portable LeadCare-II analyser. Participants included 291 younger children (3-months to 3-years-old), 271 older children (4-9-years-old), 412 mothers and 216 fathers from 13 townships with diverse levels of Pb contamination. The Blood Lead Levels (BLL) ranged from 1.65 to 162  μg/dL, with residents from Kasanda (mean 45.7  μg/dL) recording the highest BLL while Hamududu residents recorded the lowest (mean 3.3  μg/dL). Of the total number of children sampled (n = 562), 23% exceeded the 45  μg/dL, the threshold required for chelation therapy. A few children (5) exceeded the 100  μg/dL whereas none of the parents exceeded the 100  μg/dL value. Children had higher BLL than parents, with peak BLL-recorded at the age of 2-years-old. Lead exposure differences in Kabwe were attributed to distance and direction from the mine, with younger children at highest risk. Exposure levels in parents were equally alarming. For prompt diagnosis and treatment, a portable point-of-care devise such as a LeadCare-II would be preferable in Kabwe.

Association of childhood blood lead levels with firearm violence perpetration and victimization in Milwaukee

Childhood lead exposure impairs future decision-making and may influence criminal behavior, but its role in future firearm violence is unclear. Using public health, education, and criminal justice datasets linked at the individual level, we studied a population-based cohort of all persons born between June 1, 1986 and December 31, 2003 with a valid blood lead test before age 6 years and stable Milwaukee residency (n = 89,129). We estimated associations with firearm violence perpetration (n = 553) and victimization (n = 983) using logistic regression, adjusting for temporal trends, child sex, race, and neighborhood socioeconomic status. Increasing risks for firearm violence perpetration and victimization were found in each higher category of blood lead compared to the lowest, after adjusting for confounding. For perpetration, risk ratios (RR) for increasing comparisons of mean blood lead in categories of ≥5 < 10, ≥10 < 20, and ≥20 μg/dL compared to persons with mean blood lead < 5 μg/dL, were: RR 2.3 (95% CI 1.6, 3.3), RR 2.5 (95% CI 1.7, 3.9), and RR 2.8 (95% CI 1.8, 4.4). For victimization, the same increasing categoric comparisons were: RR 1.8 (95% CI 1.4, 2.3), RR 2.4 (95% CI 1.8, 3.2), RR 3.3 (95% CI 2.4, 4.5). The proportion of firearm violence attributable to blood lead ≥5 μg/dL was 56% for perpetration and 51% for victimization. In Milwaukee, during a period of high lead exposures, childhood levels may have substantially contributed to adult firearm violence. While we cannot definitively conclude causality, the possibility that over half of firearm violence among this sample might be due to lead exposure suggests the potential importance of lead exposure reduction in firearm violence prevention efforts.

Recruitment strategies and challenges: Lessons learned from a coal ash and children's health study

The purpose of this paper is to describe the approaches and recruitment strategies of a study focused on the impact of coal fly ash on neurobehavioral performance among children living in proximity to coal-burning power plants. Challenges encountered with each recruitment approach are highlighted as well as solutions used to overcome those challenges and ultimately enroll children and one of their parents or guardians. To ensure participants were distributed throughout the study area, geographical information systems were used to guide recruitment and achieve the target sample size (N = 300). Several approaches were employed to recruit the number of needed participants, including "shoe leather" or door-to-door recruitment, placement of flyers and brochures in public spaces, mailings to targeted addresses, media announcements, and local government outreach. Since September 2015, 265 participants have been enrolled in the study using a combination of the described recruitment approaches. Even with a well-designed plan, it is important to re-examine strategies at every step to maximize recruitment efforts. Researcher flexibility in adapting to new strategies is vital in facilitating recruitment efforts, and the recruitment of participants in the study remains a dynamic and evolving process.

Standards for Studies of Neurological Prognostication in Comatose Survivors of Cardiac Arrest: A Scientific Statement From the American Heart Association

Significant improvements have been achieved in cardiac arrest resuscitation and postarrest resuscitation care, but mortality remains high. Most of the poor outcomes and deaths of cardiac arrest survivors have been attributed to widespread brain injury. This brain injury, commonly manifested as a comatose state, is a marker of poor outcome and a major basis for unfavorable neurological prognostication. Accurate prognostication is important to avoid pursuing futile treatments when poor outcome is inevitable but also to avoid an inappropriate withdrawal of life-sustaining treatment in patients who may otherwise have a chance of achieving meaningful neurological recovery. Inaccurate neurological prognostication leading to withdrawal of life-sustaining treatment and deaths may significantly bias clinical studies, leading to failure in detecting the true study outcomes. The American Heart Association Emergency Cardiovascular Care Science Subcommittee organized a writing group composed of adult and pediatric experts from neurology, cardiology, emergency medicine, intensive care medicine, and nursing to review existing neurological prognostication studies, the practice of neurological prognostication, and withdrawal of life-sustaining treatment. The writing group determined that the overall quality of existing neurological prognostication studies is low. As a consequence, the degree of confidence in the predictors and the subsequent outcomes is also low. Therefore, the writing group suggests that neurological prognostication parameters need to be approached as index tests based on relevant neurological functions that are directly related to the functional outcome and contribute to the quality of life of cardiac arrest survivors. Suggestions to improve the quality of adult and pediatric neurological prognostication studies are provided.

Antimicrobial Resistance of Salmonella spp. Isolates and Heavy Metal Traces from Rodent Meat Purchased from Roadside Markets, Central Thailand

Although game meat consumption is widespread across the globe, involving a great diversity of species in very different ecological and sociocultural environments, the safety of wild meat products is rarely assessed routinely. We conducted a survey to evaluate the safety of two rodents products (Rattus tanezumi and Bandicota indica) purchased from roadside markets in central Thailand. Total aerobic bacteria and Escherichia coli counts measured were above Thai poultry product standards for 83.3% and 100% of the samples, respectively (n = 108), although there was no difference between rat species (analysis of variance [ANOVA], p > 0.05). Salmonella spp. were isolated from 32% of the swabs collected (67/208), including 19 different serovars. All strains were resistant or partially resistant to at least 2 of the 16 antibiotics tested, with levels of resistance varying greatly among antibiotics (e.g., 97% of strains sensitive to ciprofloxacin and 98.5% of strains resistant to cloxacillin). Detectable traces of Cd and Pb were found in 98% and 46% of the samples analyzed, respectively (n = 61). Pb and Cd concentrations measured in the kidneys of R. tanezumi were significantly higher than in the liver and muscles and significantly higher than B. indica muscles and kidneys but not liver (ANOVA, p < 0.05). These results highlight potential health hazards that may be associated with rodent-meat consumption, including contamination by coliform bacteria, multiresistant Salmonella spp. strains, and heavy metals. The significance of these results for public health cannot be determined precisely in the absence of appropriate standards, and information gaps remain regarding the frequency of rodent-meat consumption and the origin of bacterial and heavy metal contaminations (i.e., capture environment or during carcass handling and processing). We suggest that appropriate information and training on best hygienic practices for preparing, cooking, and preserving rodent meat should be provided to the producers and to the consumers.

Vitamin D Receptor FokI, ApaI, and TaqI Polymorphisms in Lead Exposed Subjects From Saudi Arabia

Vitamin D receptor (VDR) gene polymorphisms were reported to influence blood lead levels (BLL) and the response of subjects to the symptoms of lead toxicity. However, no studies have been conducted in the Saudi Arabian population which has unique ethnicity and socio-demographic features. This study examined the polymorphisms in exon 2 (allele 1) and intron 8 (allele 2 and allele 3) of VDR gene and their relation to BLLs. As per the CDC guidelines, the recruited lead-exposed workers (N = 130) were categorized to two groups viz., low BLL group (<10 μg/dL) and high BLL group (>10 μg/dL). The low BLL group had a mean BLL of 4.37 μg/dL, while the high BLL group had levels of 18.12 μg/dL (p < 0.001). Overall, the genetic variants, TC and CC in the VDR FokI were significantly associated with a risk of lead toxicity and the allele "C" was a risk factor (p = 0.00026). Furthermore, the TT genotype of VDR ApaI significantly increased the risk of developing lead poisoning (p = 0.0006). The VDR TaqI SNP was not significantly associated with lead toxicity. The highest BLLs for VDR FokI-CC, VDR ApaI-GG, and VDR TaqI-TT genotypes from High BLL group were 18.42, 15.26, and 18.75 μg/dL, respectively. Older age (51-60 years) was found to be a significant confounding factor for BLLs (p = 0.012). Additional studies in larger sample sizes are needed to firmly establish the role of VDR genotypes and genetic susceptibility to lead poisoning.

Metal concentrations in pregnant women and neonates from informal electronic waste recycling

Electronic waste (e-waste) is the fastest growing solid waste stream worldwide and mostly ends up in developing countries where residents use primitive methods for recycling. The most infamous e-waste recycling town, Guiyu in Southeast China, has been recycling since the mid-1990s. E-waste contains several harmful chemicals, including lead (Pb), cadmium (Cd), chromium (Cr), and manganese (Mn). In 2011-12, the e-waste Recycling Exposures and Community Health (e-REACH) Study enrolled 634 pregnant women living in Guiyu and Haojiang, a control site, both in Shantou, China. The women completed a questionnaire and gave maternal blood, cord blood, and maternal urine, which were analyzed for Pb, Cd, Cr, and Mn. Maternal blood Pb, Cd, and Cr concentrations were significantly higher in Guiyu compared to Haojiang. In Guiyu, the geometric mean of Pb concentration in maternal blood was 6.66 µg/dL (range: 1.87-27.09 µg/dL) and was 1.74-fold greater than in Haojiang (95% CI: 1.60, 1.89). In cord blood, Pb concentration was 1.53-fold higher in Guiyu (95% CI: 1.38, 1.68). In maternal urine, Cd (ratio: 2.15, 95% CI: 1.72, 2.69) and Mn (ratio: 2.60, 95% CI: 2.04, 3.31) concentrations were significantly higher in Guiyu in comparison to Haojiang. In conclusion, pregnant women in Guiyu were at risk for increased exposure to heavy metals.

Neuromodulatory effects of ethyl acetate fraction of Zingiber officinale Roscoe extract in rats with lead-induced oxidative stress

OBJECTIVE

This study investigated the ameliorative potential of Zingiber officinale Roscoe extract against lead-induced brain damage in rats.

METHODS

Thirty male rats were divided into 5 groups of 6 rats each. Lead-acetate toxicity was induced by intraperitoneal injection (10 mg/kg body weight (b.w.)) in Groups B-E. Group A (control) and Group B (lead-acetate) were left untreated; vitamin C (200 mg/kg b.w.) was administered to Group C; ethyl acetate fraction from Z. officinale extract (200 and 100 mg/kg b.w.) was administered to Group D and E by oral gavage once daily for 7 days. Changes in the content of some key marker enzymes such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO), epinephrine, dopamine, Na+/K+-ATPase, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as malonaldehyde (MDA) levels were determined in serum.

RESULTS

Exposure to lead acetate resulted in a significant decrease (P < 0.05) in the activities of BChE, AChE, Na+/K+-ATPase, SOD, CAT and GPx with a corresponding increase in the levels of MDA, xanthine oxidase, epinephrine, dopamine and MAO relative to the control group. Levels of all disrupted parameters were alleviated by co-administration of Z. officinale fraction and by the standard drug, vitamin C.

CONCLUSION

These results suggest that ethyl acetate fraction of Z. officinale extract attenuates lead-induced brain damage and might have therapeutic potential as a supplement that can be applied in lead poisoning.

Blood concentrations of lead, cadmium, mercury and their association with biomarkers of DNA oxidative damage in preschool children living in an e-waste recycling area

Reactive oxygen species (ROS)-induced DNA damage occurs in heavy metal exposure, but the simultaneous effect on DNA repair is unknown. We investigated the influence of co-exposure of lead (Pb), cadmium (Cd), and mercury (Hg) on 8-hydroxydeoxyguanosine (8-OHdG) and human repair enzyme 8-oxoguanine DNA glycosylase (hOGG1) mRNA levels in exposed children to evaluate the imbalance of DNA damage and repair. Children within the age range of 3-6 years from a primitive electronic waste (e-waste) recycling town were chosen as participants to represent a heavy metal-exposed population. 8-OHdG in the children's urine was assessed for heavy metal-induced oxidative effects, and the hOGG1 mRNA level in their blood represented the DNA repair ability of the children. Among the children surveyed, 88.14% (104/118) had a blood Pb level >5 μg/dL, 22.03% (26/118) had a blood Cd level >1 μg/dL, and 62.11% (59/95) had a blood Hg level >10 μg/dL. Having an e-waste workshop near the house was a risk factor contributing to high blood Pb (r _s  = 0.273, p < 0.01), while Cd and Hg exposure could have come from other contaminant sources. Preschool children of fathers who had a college or university education had significantly lower 8-OHdG levels (median 242.76 ng/g creatinine, range 154.62-407.79 ng/g creatinine) than did children of fathers who had less education (p = 0.035). However, we did not observe a significant difference in the mRNA expression levels of hOGG1 between the different variables. Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels (β _Q2 = 0.362, 95% CI 0.111-0.542; β _Q3 = 0.347, 95% CI 0.103-0.531; β _Q4 = 0.314, 95% CI 0.087-0.557). Associations between blood Hg levels and 8-OHdG were less apparent. Compared with low levels of blood Hg (quartile 1), elevated blood Hg levels (quartile 2) were associated with higher 8-OHdG levels (β _Q2 = 0.236, 95% CI 0.039-0.406). Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels.

Lead and cadmium excretion in feces and urine of children from polluted townships near a lead-zinc mine in Kabwe, Zambia

Lead (Pb) and cadmium (Cd) are toxic metals that exist ubiquitously in the environment. Children in polluted areas are particularly vulnerable to metal exposure, where clinical signs and symptoms could be nonspecific. Absorbed metals are excreted primarily in urine and reflect exposure from all sources. We analyzed Pb and Cd concentrations in blood, feces and urine of children from polluted townships near a lead-zinc mine in Kabwe, Zambia, to determine concurrent childhood exposure to the metals. Moreover, the study determined the Pb and Cd relationships among urine, feces and blood as well as accessed the potential of urine and fecal analysis for biomonitoring of Pb and Cd exposure in children. Fecal Pb (up to 2252 mg/kg, dry weight) and urine Pb (up to 2914 μg/L) were extremely high. Concentrations of Cd in blood (Cd-B) of up to 7.7 μg/L, fecal (up to 4.49 mg/kg, dry weight) and urine (up to 18.1 μg/L) samples were elevated. metal levels were higher in younger children (0-3 years old) than older children (4-7). Positive correlations were recorded for Pb and Cd among blood, urine and fecal samples whereas negative correlations were recorded with age. These findings indicate children are exposed to both metals at their current home environment. Moreover, urine and feces could be useful for biomonitoring of metals due to their strong relationships with blood levels. There is need to conduct a clinical evaluation of the affected children to fully appreciate the health impact of these metal exposure.

Environmental Assessment and Blood Lead Levels of Children in Owino Uhuru and Bangladesh Settlements in Kenya

BACKGROUND

Lead exposure is linked to intellectual disability and anemia in children. The United States Centers for Disease Control and Prevention (CDC) recommends biomonitoring of blood lead levels (BLLs) in children with BLL ≥5 μg/dL and chelation therapy for those with BLL ≥45 μg/dL.

OBJECTIVES

This study aimed to determine blood and environmental lead levels and risk factors associated with elevated BLL among children from Owino Uhuru and Bangladesh settlements in Mombasa County, Kenya.

METHODS

The present study is a population-based, cross-sectional study of children aged 12-59 months randomly selected from households in two neighboring settlements, Owino Uhuru, which has a lead smelter, and Bangladesh settlement (no smelter). Structured questionnaires were administered to parents and 1-3 ml venous blood drawn from each child was tested for lead using a LeadCare ® II portable analyzer. Environmental samples collected from half of the sampled households were tested for lead using graphite furnace atomic absorption spectroscopy.

RESULTS

We enrolled 130 children, 65 from each settlement. Fifty-nine (45%) were males and the median age was 39 months (interquartile range (IQR): 30-52 months). BLLs ranged from 1 μg/dL to 31 μg/dL, with 45 (69%) children from Owino Uhuru and 18 (28%) children from Bangladesh settlement with BLLs >5 μg/dL. For Owino Uhuru, the geometric mean BLL in children was 7.4 μg/dL (geometric standard deviation (GSD); 1.9) compared to 3.7 μg/dL (GSD: 1.9) in Bangladesh settlement (p<0.05). The geometric mean lead concentration of soil samples from Owino Uhuru was 146.5 mg/Kg (GSD: 5.2) and 11.5 mg/Kg (GSD: 3.9) (p<0.001) in Bangladesh settlement. Children who resided <200 m from the lead smelter were more likely to have a BLL ≥5 μg/dL than children residing ≥200 m from the lead smelter (adjusted odds ratio (aOR): 33.6 (95% confidence interval (CI): 7.4-153.3). Males were also more likely than females to have a BLL ≥5 μg/dL (39, 62%) compared to a BLL<5 μg/dL [aOR: 2.4 (95% CI: 1.0-5.5)].

CONCLUSIONS

Children in Owino Uhuru had significantly higher BLLs compared with children in Bangladesh settlement. Interventions to diminish continued exposure to lead in the settlement should be undertaken. Continued monitoring of levels in children with detectable levels can evaluate whether interventions to reduce exposure are effective.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

Scientific approval for the study was obtained from the Ministry of Health, lead poisoning technical working group. Since this investigation was considered a public health response of immediate concern, expedited ethical approval was obtained from the Kenya Medical Research Institute and further approval from the Mombasa County Department of Health Services. The investigation was considered a non-research public health response activity by the CDC.

COMPETING INTERESTS

The authors declare no competing financial interests.

Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children

Lead (Pb) is a developmental neurotoxicant and can cause abnormal development of the nervous system in children. Hence, the aim of this study was to investigate the effect of Pb exposure on child olfactory memory by correlating the blood Pb levels of children in Guiyu with olfactory memory tests. We recruited 61 preschool children, 4- to 7-years of age, from Guiyu and 57 children from Haojiang. The mean blood Pb level of Guiyu children was 9.40 μg/dL, significantly higher than the 5.04 μg/dL mean blood Pb level of Haojiang children. In addition, approximately 23% of Guiyu children had blood Pb levels exceeding 10.00 μg/dL. The correlation analysis showed that blood Pb levels in children highly correlated with e-waste contact (r_s = 0.393). Moreover, the mean concentration of serum BDNF in Guiyu children (35.91 ng/ml) was higher than for Haojiang (28.10 ng/ml) and was positively correlated with blood Pb levels. Both item and source olfactory memory tests at 15 min, 5 h and 24 h after odor exposure showed that scores were lower in Guiyu children indicative of reduced olfactory memory in Guiyu children. Olfactory memory tests scores negatively correlated with blood Pb and serum BDNF levels, but were positively associated with parental education levels. At the same time, scores of both tests on children in the high blood Pb level group (blood Pb levels > 5.00 μg/dL) were lower than those in the low blood Pb level group (blood Pb levels ≤ 5.00 μg/dL), implying that Pb exposure decreases olfactory memory in children. Our findings suggest that Pb exposure in e-waste recycling and dismantling areas could result in an increase in serum BDNF level and a decrease in child olfactory memory, in addition, BDNF might be involved in olfactory memory impairment.

Alleviation of ginsenoside Rg1 on hematopoietic homeostasis defects caused by lead-acetate

The hematopoietic system is one of the potential targets of lead intoxication. Recognition of the lead-related deleterious outcomes promotes us to explore the potential therapeutic intervention. Here, we show that ginsenoside Rg1 (Rg1), extracted from the Chinese herb Panax ginseng, remarkably ameliorates the lead acetate-caused hematological index distortion as well as advanced hematopoietic stem cells (HSCs) aging and aging associated inflammation response. Specifically, Rg1 administration alleviated the increment of aging associated p53-p21-Rb signaling in aged HSCs induced by lead acetate. It also led a reduction of the lead acetate-induced increased inflammation level in blood plasma, which also partly contribute the aged HSCs rejuvenation. In conclusion, our results indicate that ginsenoside Rg1 therapeutically alleviated the essential blood deficits and advanced HSCs aging by lead acetate exposure, by which it could be viewed as a potential candidate for lead acetate-caused blood toxicity treatment.

Genome-wide gene by lead exposure interaction analysis identifies UNC5D as a candidate gene for neurodevelopment

BACKGROUND

Neurodevelopment is a complex process involving both genetic and environmental factors. Prenatal exposure to lead (Pb) has been associated with lower performance on neurodevelopmental tests. Adverse neurodevelopmental outcomes are more frequent and/or more severe when toxic exposures interact with genetic susceptibility.

METHODS

To explore possible loci associated with increased susceptibility to prenatal Pb exposure, we performed a genome-wide gene-environment interaction study (GWIS) in young children from Mexico (n = 390) and Bangladesh (n = 497). Prenatal Pb exposure was estimated by cord blood Pb concentration. Neurodevelopment was assessed using the Bayley Scales of Infant Development.

RESULTS

We identified a locus on chromosome 8, containing UNC5D, and demonstrated evidence of its genome-wide significance with mental composite scores (rs9642758, p _meta = 4.35 × 10^-6). Within this locus, the joint effects of two independent single nucleotide polymorphisms (SNPs, rs9642758 and rs10503970) had a p-value of 4.38 × 10^-9 for mental composite scores. Correlating GWIS results with in vitro transcriptomic profiles identified one common gene, SLC1A5, which is involved in synaptic function, neuronal development, and excitotoxicity. Further analysis revealed interconnected interactions that formed a large network of 52 genes enriched with oxidative stress genes and neurodevelopmental genes.

CONCLUSIONS

Our findings suggest that certain genetic polymorphisms within/near genes relevant to neurodevelopment might modify the toxic effects of Pb exposure via oxidative stress.

What are the blood lead levels of children living in Latin America and the Caribbean?

INTRODUCTION

Information on the prevalence of lead exposure is essential to formulate efficient public health policies. Developed countries have implemented successful public policies for the prevention and control of lead poisoning. In the United States, Canada, Japan and the European Union, for instance, periodically repeated prevalence studies show that blood lead levels (BLLs) in children have decreased overall. Although BLL of Latino children in the U.S. have also dropped in recent years, the geometric mean remains higher than that of white children. Little is known about lead exposure in children in Latin America and the Caribbean (LAC). In this review, we responded to two questions: What is currently known about lead sources and levels in children in LAC? Are there public policies to prevent children's exposure to lead in LAC?

METHOD

We conducted a literature review covering the period from January 2000 to March 2014 in the PubMed and Lilacs databases to obtain English, Portuguese and Spanish language studies reporting the prevalence of BLLs in children aged 0-18years living in LAC countries. No specific analytical method was selected, and given the scarcity of data, the study was highly inclusive.

RESULTS

Fifty-six papers were selected from 16 different LAC countries. The children's BLLs found in this review are high (≥10μg/dL) compared to BLLs for the same age group in the U. S. However, most studies reported an association with some type of "lead hot spot", in which children can be exposed to lead levels similar to those of occupational settings. Only Peru and Mexico reported BLLs in children from population-based studies.

CONCLUSIONS

Most BLLs prevalence studies carried out in LAC were in areas with known emission sources. The percentage of children at risk of lead poisoning in LAC is unknown, and probably underestimated. Thus, there is an urgent need to establish public health policies to quantify and prevent lead poisoning, specifically by prioritizing the identification and control of "hot spots".

Considerable decrease of antibody titers against measles, mumps, and rubella in preschool children from an e-waste recycling area

Data on vaccination effects in children chronically exposed to heavy metals are extremely scarce. This study aims to investigate the immune responsiveness to measles, mumps, and rubella (MMR) vaccination in children from an e-waste recycling area. 378 healthy children from Guiyu (exposed group) and Haojiang (reference group) were surveyed. Blood lead (Pb) levels were measured by graphite furnace atomic absorption. Titers of antibodies against MMR were quantified by ELISA. Blood Pb levels of children from the exposed group were significantly higher than those from the reference group (5.61μg/dL vs. 3.57μg/dL, p<0.001). In contrast, the antibody titers against MMR of the children from the exposed group were significantly lower than those from the reference group. The median titer of the anti-measles antibody of the exposed group was 669.64mIU/mL, with an interquartile range of 372.88-1068.42mIU/mL; this was decreased by nearly 40% compared to that of the reference group (median 1046.79mIU/mL, interquartile range 603.29-1733.10mIU/mL). For antibody titers against mumps, there was an about 45% decrease in the exposed group (median 272.24U/mL, interquartile range 95.19-590.16U/mL), compared to the reference group (median 491.78U/mL, interquartile range 183.38-945.96U/mL). In the case of rubella, the median titer of the antibody was also significantly lower in the exposed group (median 37.08IU/mL, interquartile range 17.67-66.66IU/mL) compared to the reference group (median 66.50IU/mL, interquartile range 25.32-105.59IU/mL); the decrease in this case was nearly 44%. The proportion of children whose antibody titers against MMR were below protective level in the exposed group was higher than it was in the reference group. The present study demonstrates that the immune responsiveness to routine vaccination was suppressed in children chronically exposed to lead. Thus, the vaccination strategies for these children living in an e-waste recycling area should be modified.

Assessment of blood lead level declines in an area of historical mining with a holistic remediation and abatement program

Lead exposure and blood lead levels (BLLs) in the United States have declined dramatically since the 1970s as many widespread lead uses have been discontinued. Large scale mining and mineral processing represents an additional localized source of potential lead exposure in many historical mining communities, such as Butte, Montana. After 25 years of ongoing remediation efforts and a residential metals abatement program that includes blood lead monitoring of Butte children, examination of blood lead trends offers a unique opportunity to assess the effectiveness of Butte's lead source and exposure reduction measures. This study examined BLL trends in Butte children ages 1-5 (n= 2796) from 2003-2010 as compared to a reference dataset matched for similar demographic characteristics over the same period. Blood lead differences across Butte during the same period are also examined. Findings are interpreted with respect to effectiveness of remediation and other factors potentially contributing to ongoing exposure concerns.

REFERENCE POPULATION COMPARISON

BLLs from Butte were compared with a reference dataset (n=2937) derived from the National Health and Nutrition Examination Survey. The reference dataset was initially matched for child age and sample dates. Additional demographic factors associated with higher BLLs were then evaluated. Weights were applied to make the reference dataset more consistent with the Butte dataset for the three factors that were most disparate (poverty-to-income ratio, house age, and race/ethnicity). A weighted linear mixed regression model showed Butte geometric mean BLLs were higher than reference BLLs for 2003-2004 (3.48vs. 2.05µg/dL), 2005-2006 (2.65vs. 1.80µg/dL), and 2007-2008 (2.2vs. 1.72µg/dL), but comparable for 2009-2010 (1.53vs. 1.51µg/dL). This trend suggests that, over time, the impact of other factors that may be associated with Butte BLLs has been reduced.

COMPARISON ACROSS BUTTE

Neighborhood differences were examined by dividing the Butte dataset into the older area called "Uptown", located at higher elevation atop historical mine workings, and "the Flats", at lower elevation and more recently developed. Significant declines in BLLs were observed over time in both areas, though Uptown had slightly higher BLLs than the Flats (2003-2004: 3.57vs. 3.45µg/dL, p=0.7; 2005-2006: 2.84vs. 2.52µg/dL, p=0.1; 2007-2008: 2.58vs. 1.99µg/dL, p=0.001; 2009-2010: 1.71vs. 1.44µg/dL, p=0.02). BLLs were higher when tested in summer/fall than in winter/spring for both neighborhoods, and statistically higher BLLs were found for children in Uptown living in properties built before 1940. Neighborhood differences and the persistence of a greater percentage of high BLLs (>5µg/dL) in Butte vs. the reference dataset support continuation of the home lead abatement program.

CONCLUSIONS

Butte BLL declines likely reflect the cumulative effectiveness of screening efforts, community-wide remediation, and the ongoing metals abatement program in Butte in addition to other factors not accounted for by this study. As evidenced in Butte, abatement programs that include home evaluations and assistance in addressing multiple sources of lead exposure can be an important complement to community-wide soil remediation activities.

Zinc, lead, and cadmium levels in serum and milk of lactating women in Ibadan, Nigeria

Zinc (Zn) is known to interact with lead (Pb) and cadmium (Cd) reversing their toxicity and reducing their concentrations. However, lactating women are at high risk of developing Zn deficiency, which may result in Pb and Cd intoxication or increased exposure of breast-fed infants to Pb and Cd from breast milk. The aim of this study was to determine Zn, Pb, and Cd concentrations and examine their relationship in serum and breast milk of lactating women in Ibadan, Nigeria. Ninety-two lactating women were recruited into this study. Anthropometric measurements were assessed by standard methods while serum and breast milk concentrations of Zn, Pb, and Cd were assessed by atomic absorption spectrophotometry. Data analyzed statistically by Student’s t test, Pearson’s correlation coefficient, and a multiple regression model were significant at p < 0.05. Zn deficiency was observed in 12 (17.1%) of lactating women. Breast milk levels of Zn, Pb, and Cd were significantly higher than their levels in serum, whereas the ratios Zn:Pb and Zn:Cd in milk were significantly less than serum ratios. Significant negative correlation was observed between milk Pb and serum Zn:Pb while milk Cd correlated positively with milk Zn. Significant positive correlations were observed between serum Zn and serum Zn:Pb, serum Zn and serum Zn:Cd, as well as serum Zn:Cd and serum Zn:Pb. Serum Cd and serum Zn were significantly negatively related. Significant negative correlations between serum Pb and serum Zn:Pb as well as milk Zn:Pb. Serum Cd and serum Zn:Pb as well as serum Zn:Cd correlated negatively. Milk Cd and Zn/Cd positively related with milk Pb while milk Zn was a negatively related with milk Pb in a multiple regression model ( R2 = 0.333; p = 0.023). Breast milk may be contaminated by toxic metals. However, Zn supplementation in deficient mothers may protect maternal and infant health.

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.

Proximity of residence to an old mineral storage site in Chile and blood lead levels in children

Evidence suggests that an old mineral storage site removed in 1998 due to high lead content, remains as a source of exposure in the city of Antofagasta, Chile. The aim was to determine the association between blood lead levels in children and the residential proximity to the old mineral storage site. A cross sectional study was conducted with 185 children aged 7 to 16 years. The outcome variable was blood lead levels measured in 2005. The exposure variable was the distance between the current residence and the old mineral storage site. The distance was measured in meters by Geographic Information System (GIS). The median blood lead level in 2005 was 3.3μg/dL (interquartile range ‒ IQR: 2.0-4.3). A significant inverse association was found between the residential distance to the old mineral storage site and the blood lead levels in children, after adjusting by confounders (β: -0.04; 95%CI: -0.09; -0.01). This result suggests that the old mineral storage site continues to be a source of lead exposure for the children living nearby.

Evaluation of calcium and lead interaction, in addition to their impact on thyroid functions in hyper and hypothyroid patients

There is compelling evidence in support of interaction between calcium (Ca) and lead (Pb) in thyroid disorders. The aim of present study was to compare the level of Ca and Pb with thyroid hormones such as thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxin (FT4) in serum samples of hyperthyroid (HPRT) and hypothyroid (HPOT) patients of both genders. For comparative purpose, age-matched (25-50 years) subjects having no thyroid disorders were selected as referents/controls. The serum samples were acid-digested prior to analysis by atomic absorption spectrometry. The validity and accuracy of the methodology were checked by certified reference materials. The resulted data indicates that the mean values of Ca in serum samples of HPRT patients were significantly higher than those of referent subjects (p < 0.01), while reverse pattern was observed in the case of HPOT patients. The level of Pb was higher in the serum samples of both types of thyroid patients, but difference was significant in case of HPOT patients as compare to referent subjects (p < 0.01). A negative correlation was observed between serum Ca levels and TSH of HPRT patients (-r = 0.37-0.39, p < 0.01), while FT3 and FT4 have positive correlation (r = 0.49-0.52 and r = 0.46-0.47), p values <0.01. The Pb in serum had positive correlation with TSH (r = 0.48-0.51, p < 0.005), while negative correlation was observed for FT3 and FT4 (-r = 0.55-0.56, 0.5-0.54, p < 0.05) in HPRT patients. On the other hand, a reverse pattern was observed, for correlation of Ca and Pb with thyroid functions in HPOT patients.

Lead Toxicity, Antioxidant Defense and Environment

Environmental and occupational exposure to a large number of chemicals occurs at various stages throughout human life. Many of these are devoid of toxicity, but some could pose a significant health risk, i.e. the exposure to environmental xenobiotic metals as lead, mercury (Sinicropi et al. 2010a; Carocci et al. 2014), cadmium, etc. In particular, lead has long been a widespread public concern (Basha and Reddy 2010). Lead is one of the earliest heavy metals discovered by men. Due to its unique properties, as low melting point, softness, malleability, ductility, and resistance to corrosion, men have used lead for the last 5000 years in a wide range of applications.

Evaluation and management of lead exposure

Lead, which is widely used in industry, is a common element found in low concentrations in the Earth's crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, hematopoietic system, and nervous system. Having a carcinogenic risk as well, the IARC classifies inorganic lead compounds as probably carcinogenic to humans (Group 2A). Occupational lead poisonings have decreased due to the efforts to reduce the lead concentrations in the working environment. In contrast, health hazards associated with long-term environmental exposure to low concentrations of lead have been reported steadily. In particular, chronic exposure to low concentrations of lead has been reported to induce cognitive behavioral disturbances in children. It is almost impossible to remove lead completely from the human body, and it is not easy to treat health hazards due to lead exposure. Therefore, reduction and prevention of lead exposure are very important. We reviewed the toxicity and health hazards, monitoring and evaluation, and management of lead exposure.

Risk factors for elevated blood lead levels among children aged 6-36 months living in Greece

BACKGROUND

Childhood lead poisoning remains a critical environmental health concern because even low blood lead levels (BLLs) can result in permanent adverse health effects. Social factors and living conditions have been correlated with BLLs. There is no recent survey about the prevalence of elevated BLLs among children in Greece. The purpose of this study was to assess BLLs among children aged 6-36 months born and living in Greece and to evaluate their association with demographic, socio-economic and housing conditions.

METHODS

In a cross-sectional hospital-based study including 814 randomly selected children aged 6-36 months, BLLs and haematological parameters were evaluated. A questionnaire investigating demographic and socio-economic conditions was completed in all children. Statistical analysis was performed using STATA for Windows v.8.5, and P < 0.05 was considered statistically significant.

RESULTS

The mean BLLs of the population were 2.78 (SD = 2.34) µg/dl, and the median was 2.02 µg/dl; 11.7% had BLLs above 5 µg/dl, while 15 children (1.8%) exceeded 10 µg/dl. Being a toddler, being Roma or Asian, living in an industrial/low-income neighbourhood or in an old house, using traditional herbs and/or spices and having a mother with a manual occupation were independent risk factors for elevated BLLs.

CONCLUSION

Lead exposure remains a threat for optimal health especially for toddlers and children of socio-economically disadvantaged families living in Greece. A nationwide survey to assess lead exposure in children is necessary to guide prevention governmental policies.

Impact of the Great East Japan Earthquake on Child's IQ

OBJECTIVE

To assess the neurodevelopmental effects of the Great East Japan Earthquake in resident children.

STUDY DESIGN

The disaster on March 11, 2011, caused severe damage to the Sanriku coastal area, where we had been conducting a birth cohort study since 2003. It occurred in the middle of our 7-year-old examination. Approximately 500 mother-child pairs were compulsorily divided into 2 groups: 123 children finished the examination in the predisaster period, and 289 did in the postdisaster period. The remainder died or moved from that area. At the time of 7-year-old examination, we administered the Wechsler Intelligence Scale for Children-Third Edition and electrocardiography to assess autonomic function. According to the Child Behavior Checklist for ages 2-3 years and the Kaufman Assessment Battery for Children that had been administered at 30 months and 42 months of age, respectively, there were no significant differences in them between the 2 groups.

RESULTS

Verbal IQ, including information, arithmetic, and vocabulary subscores of the Wechsler Intelligence Scale for Children-Third Edition, at 7 years of age was significantly lower in the postdisaster group than in the predisaster group. However, there were no significant differences in performance IQ, full-scale IQ, or autonomic nervous indicators between the 2 groups.

CONCLUSIONS

Since many schools were utilized as primary refuges after the disaster, the deficits in verbal IQ of 7-year-old children may have been due to the interrupted schooling. Further follow-up and more specific posttraumatic stress disorder testing will be required to determine the cause and long-term implications.

Screening for childhood lead poisoning in the industrial region of Fez, Morocco

The study objectives were to estimate lead poisoning prevalence among children living next to an industrial area, to compare it to that in a control population, and to establish clinical and biological follow-up of the poisoned children. This is a descriptive cross-sectional study including 150 children (exposed and unexposed) performed between January 2012 and April 2013. It was meant to determine blood lead levels (BLLs) in children considered to be an exposed population (EP N 90), living in the industrial area Ain Nokb Fez compared with BLLs of children of other areas belonging to the same city supposed to be unexposed [UP (N = 60)]. A sociodemographic questionnaire was obtained, and a blood lead analysis was performed. Clinical and biological follow-up has been performed of poisoned children. The sample consisted of 90 EP children with an average age of 6.82 ± 3.32 years and male-to-female sex ratio (SR) of 1.5 and 60 UP children with an average age of 6.45 ± 3.29 years and an SR of 1.2. Among the 150 children recruited, the average of BLLs was 58.21 ± 36 µg/L (18-202.3 μg/L). The average of BLLs in EP children (71 ± 40 µg/L) was statistically greater (p < 0.0001) than that registered in UP children (38 ± 13 µg/L). All poisoned children belonged to the EP group at a prevalence of 21.1 %. The clinical and biological examinations of poisoned children showed a few perturbations such as anemia, hypocalcaemia, and deficiencies in magnesium and iron. No renal disease or objective neurological disorders were observed. In the follow-up of the children with BLL ≥100 µg/L (19 cases). BLL monitoring showed a significant decrease in average of blood concentration ranging from 136.75 ± 32.59 to 104.58 ± 32.73 µg/L (p < 0.0001) and in lead poisoning prevalence (p < 0.001), which decreased to 7.8 % from 21.1. Our study showed a high prevalence of lead poisoning (21.1 %) in EP children. The relocation of the industrial site associated with corrective and preventive measures has contributed to a decrease of exposure and lead poisoning prevalence in the aforementioned population.

Mitochondria defects are involved in lead-acetate-induced adult hematopoietic stem cell decline

Occupational high-grade lead exposure has been reduced in recent decades as a result of increased regulation. However, environmental lead exposure remains widespread, and is associated with severe toxicity implicated in human diseases. We performed oral intragastric administration of various dose lead acetate to adult Sprague Dawley rats to define the role of lead exposure in hematopoietic stem cells (HSCs) function, and to clarify its underlying mechanism. Lead acetate-exposed rats exhibited developmental abnormalities in myeloid and lymphoid lineages, and a significant decline in immune functions. It also showed HSCs functional decline associated with senescent phenotype with low grade lead acetate exposure or apoptotic phenotype with relative higher grade dose exposure. Mechanistic exploration showed a significant increase in reactive oxygen species (ROS) in the lead acetate-exposed CD90(+)CD45(-) compartment, which correlated with functional defects in cellular mitochondria. Furthermore, in vivo treatment with the antioxidant vitamin C led to reversion of the CD90(+)CD45(-) compartment functional decline. These results indicate that lead acetate perturbs the hematopoietic balance of adult HSCs, associated with cellular mitochondria defects, increased intracellular ROS generation.

Effects of curcumin and tannic acid on the aluminum- and lead-induced oxidative neurotoxicity and alterations in NMDA receptors

Exposure to aluminum (Al) and lead (Pb) can cause brain damage. Also, Pb and Al exposure alters N-methyl-d-aspartate receptor (NMDAR) subunit expression. Polyphenols such as tannic acid and curcumin are very efficient chelator for metals. The effects of curcumin and tannic acid (polyphenols) on Al(3+)- and Pb(2+)-induced oxidative stress were examined by investigating lipid peroxidation (LPO) levels, antioxidant enzyme activities, acetyl cholinesterase (AChE) activity and also NMDA receptor subunits 2A and 2B concentrations in the brain tissue of rats sub-chronically. Rats were divided into seven groups as control, Al, Pb, aluminum-tannic acid treatment (AlT), aluminum-curcumin treatment (AlC), lead-tannic acid treatment (PbT) and lead-curcumin treatment (PbC). After 16 weeks of treatment, LPO levels in the brain and hippocampus were higher in Al(3+)-exposed rats than that of Pb(2+)-exposed group. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in brain tissue of Al- and Pb-exposed rats increased significantly compared with control, while catalase (CAT) and AChE activities decreased. It was observed that metal exposure affected NR2A concentrations more than NR2B concentrations and also that polyphenol treatments increased these receptor protein concentrations.

Lead poisoning in children from townships in the vicinity of a lead-zinc mine in Kabwe, Zambia

Childhood lead poisoning is a serious public health concern worldwide. Blood lead levels exceeding 5 μg dL(-1) are considered elevated. In Kabwe, the capital of Zambia's Central Province, extensive Pb contamination of township soils in the vicinity of a Pb-Zn mine and posing serious health risk to children has been reported. We investigated BLLs in children under the age of 7 years in townships around the mine; where blood samples were collected and analyzed using an ICP-MS. All of the sampled children had BLLs exceeding 5 μg dL(-1). Children in these areas could be at serious risk of Pb toxicity as 18% of the sampled children in Chowa, 57% (Kasanda) and 25% (Makululu) had BLLs exceeding 65 μg dL(-1). Eight children had BLLs exceeding 150 μg dL(-1) with the maximum being 427.8 μg dL(-1). We recommend that medical intervention be commenced in the children with BLL exceeding 45 μg dL(-1).

Functionalized Magnetic Nanoparticles for Environmental Remediation

Water pollution by anthropogenic activities is proving to be of critical concern as the heavy metals affect aquatic organisms and can quickly disperse to large distances. This poses a risk to both human health and the aquatic biota. Hence, there is a need to treat the wastewater containing toxic metals before they are discharged into the water bodies. During recent years, magnetic nanoparticles came to the foreground of scientific interest as a potential adsorbent of novel wastewater treatment processes. Magnetic nanoparticles have received much attention due to their unique properties, such as extremely small size, high surface-area-to-volume ratio, surface modifiability, multi functionality, excellent magnetic properties, low-cost synthesis, and great biocompatibility. The multi-functional magnetic nanoparticles have been successfully applied for the reduction of toxic metal ions up to ppb level in waste-treated water. This chapter highlights the potential application of magnetic nanoparticles for the removal of heavy metals.