Update on the clinical management of childhood lead poisoning

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.

Investigation on Applying Biodegradable Material for Removal of Various Substances (Fluorides, Nitrates and Lead) from Water

Sapropel was used as a biodegradable material for water treatment. Sapropel is a sedimentary layer of a mix of organic and inorganic substances accumulated in the bottoms of lakes for thousands of years. It is a jelly-like homogeneous mass and has properties of sorption. Sapropel is used as a biosorbent and an environment-friendly fertiliser, and it is used in building materials and in the beauty industry as well. In water, there are abundant various solutes that may cause a risk to human health. Such substances include fluorides, nitrates and lead in different sources of water. The goal of this investigation is to explore and compare the efficiencies of removal of different pollutants (fluorides, nitrates and lead) from aqueous solutions upon using sapropel as a sorbent. In this research, various doses of sapropel (0.1, 0.5, 1, 5, 10, 20, 50, 100 and 200 g/L) and various mixing times (15, 30, 60, 90 and 120 min) were used for removal of fluorides, nitrates and lead from aqueous solutions. It was found that the maximum efficiency (up to 98.57%) of lead removal from aqueous solutions by sapropel was achieved when the minimum doses of it (0.1 and 0.5 g/L) were used. The most efficient removal of fluorides (64.67%) was achieved by using 200 g/L of sapropel and mixing for 120 min. However, sapropel does not adsorb nitrates from aqueous solutions.

The association between lead exposure and crime: A systematic review

Prior research has demonstrated an association between lead exposure and criminal behavior at the population-level, however studies exploring the effect of lead exposure on criminal behavior at the individual-level have not been reviewed systematically. The intent of this study is to complete a systematic review of all studies assessing individual-level exposures to lead and the outcomes of crime and antisocial behavior traits. We included peer reviewed studies that were published prior to August 2022 and were classified as cohort, cross-sectional, or case-control. Studies measuring the outcomes of crime, delinquency, violence, or aggression were included. The following databases were searched using a standardized search strategy: ProQuest Environmental Science Database, PubMed, ToxNet and the Public Affairs Information Service (PAIS). Seventeen manuscripts met our inclusion criteria. Blood lead was measured in 12 studies, bone lead in 3 studies, and dentine lead levels in 2 studies. This systematic review identified a wide range of diverse outcomes between exposure to lead at multiple windows of development and later delinquent, criminal and antisocial behavior. A review of all potential confounding variables included within each study was made, with inclusion of relevant confounders into the risk of bias tool. There is limited data at the individual level on the effects of prenatal, childhood, and adolescent lead exposure and later criminal behavior and more evidence is necessary to evaluate the magnitude of the associations seen in this review. Our review, in conjunction with the available biological evidence, suggests that an excess risk for criminal behavior in adulthood exists when an individual is exposed to lead in utero or in the early years of childhood. The authors report no conflict of interest and no funding source. Clinical trial registration: PROSPERO ID: CRD42021268379.

Lead poisoning in a 6-month-old infant: a case report

Background

Lead is a toxic element of the environment that leads to major complications once it enters the blood stream, affecting multiple organs and systems of the body.

Methods

We present a case of a 6-month-old female infant diagnosed with lead poisoning after presenting for routine child health care. The child's mother denied that the infant had a history of exposure to lead-containing substances. After a month of calcium supplementation, the patient's blood lead level remained elevated. We then tested the blood lead level of the mother and father. The results showed that the blood lead level of the mother was 77.0 μg/L and that of the father was 36.9 μg/L. The high blood lead level of the mother attracted our attention. We found that the mother had been using an external traditional Chinese medicine, Hu Wang Fen, which contains lead. After the mother's discontinuation of use of the traditional medicine, the child was treated with symptomatic treatment and chelation therapy. Subsequently, the patient's blood lead level decreased significantly.

Results

Lead toxicity can be a life-threatening problem because of its potential for severe complications. In children, there is no safe blood lead level, and the toxic effects of lead can be prevented by the awareness and avoidance of traditional Chinese medicines that may contain lead.

Conclusion

Even though the diagnosis of lead poisoning remains difficult in children, it must be taken into consideration by the clinician when treating a child using traditional Chinese medicines.

Evaluation of Essential and Toxic Elements in the Blood of 0–14-Year-Old Children in Hunan, China From 2013 to 2019: A Retrospective Analysis

Objective

The aim was to investigate the distribution and correlation of Ca, Mg, Zn, Cu, Fe, Pb, and Cd in the blood of children aged 0–14 years in Hunan, China, which may serve to provide a basis for clinical guidance on child health.

Study Design

A retrospective analysis was carried out. Concentrations of all elements were determined by atomic absorption spectrophotometry. Distributions were analyzed and compared among different age, sex, and year groups by the Kruskal–Wallis test, the chi-square test, and the Fisher's exact test. Spearman's rank correlation coefficient was used to evaluate the association between every pair of elements.

Results

A total of 46,951 children were involved in this study from 2013 to 2019. The median blood levels of elements were 13.51 μmol/L (Cu), 58.69 μmol/L (Zn), 1.70 mmol/L (Ca), 1.40 mmol/L (Mg), 7.46 mmol/L (Fe), 35.00 μg/L (Pb), and 1.00 μg/L (Cd). Girls had a higher level of Ca and lower levels of Pb and Cd than boys. Cu and Ca showed an upward trend, and Mg and Pb showed a downward trend by year. Zn and Fe increased and Ca decreased significantly with age. The deficiency rates of Fe and Zn decreased significantly by year, while Ca and Cu increased significantly by year. Cd exposure in this area was relatively low.

Conclusion

Most children had normal levels of the essential elements Ca, Cu, and Mg and the toxic elements Pb and Cd. Severe deficiencies in Zn and Fe were observed in the relatively younger children but improved with age. Persistent efforts in reducing Pb exposure might still be needed.

Environmental and health risks posed to children by artisanal gold mining: A systematic review

There are an estimated 5 million children working in artisanal and small-scale gold mines worldwide; however, the hazards are poorly characterized and often underreported. We systematically reviewed the literature on reports of hazards among children as a consequence of such activities through PubMed database using pre-defined search terms. We identified 113 articles published between 1984 and 2021 from 31 countries. Toxicological hazards were reported in 91 articles, including mercury, lead, and arsenic. Infectious hazards, noted in 18 articles, included malaria, cholera, and hepatitis. Six articles reported occupational hazards, including malnutrition, heat stroke, and reactive airway disease. Three articles reported traumatic hazards, including cave-ins, burns, animal attacks, falls, and weapon-inflected wounds. Those findings likely indicate a profound underreporting of the prevalence and consequences of such hazards among children. More work is needed both to characterize the burdens of those hazards and to address the underlying drivers of child labor in those settings.

A systematic review of clinical and laboratory findings of lead poisoning: lessons from case reports

Lead is one of the most toxic heavy metals in the environment. The present review aimed to highlight hazardous pollution sources, management, and review symptoms of lead poisonings in various parts of the world. The present study summarized the information available from case reports and case series studies from 2009 to March 2020 on the lead pollution sources and clinical symptoms. All are along with detoxification methods in infants, children, and adults. Our literature compilation includes results from 126 studies on lead poisoning. We found that traditional medication, occupational exposure, and substance abuse are as common as previously reported sources of lead exposure for children and adults. Ayurvedic medications and gunshot wounds have been identified as the most common source of exposure in the United States. However, opium and occupational exposure to the batteries were primarily seen in Iran and India. Furthermore, neurological, gastrointestinal, and hematological disorders were the most frequently occurring symptoms in lead-poisoned patients. As for therapeutic strategies, our findings confirm the safety and efficacy of chelating agents, even for infants. Our results suggest that treatment with chelating agents combined with the prevention of environmental exposure may be an excellent strategy to reduce the rate of lead poisoning. Besides, more clinical studies and long-term follow-ups are necessary to address all questions about lead poisoning management.

Trends in Blood Lead Levels in the U.S. From 1999 to 2016

INTRODUCTION

Trends in blood lead levels in the same birth cohort (generation) are necessary to identify the lead load in the population. This analysis uses a nationally representative sample to investigate the trends in blood lead levels from 1999 to 2016 by birth cohort and to revisit the association between blood lead levels and age.

METHODS

Data from the 1996 to 2016 National Health and Nutrition Examination Surveys were used to describe the distribution of blood lead levels. Trends in blood lead levels were analyzed using joinpoint regression models. Association of blood lead levels with age was conducted with both cross-sectional and birth cohort analysis. Analyses were conducted in 2020.

RESULTS

In total, 68,877 participants were included (weighted mean age=38.4 years, 50.6% female). From 1999 to 2016, the geometric mean of blood lead levels decreased from 1.68 µg/dL (95% CI=1.63, 1.74) to 0.82 µg/dL (95% CI=0.77, 0.87). The annual percentage change estimated by the joinpoint model was -4.26% (p<0.05). The associations between blood lead levels and age were "U"-shaped by cross-sectional analysis, with higher risks for the lowest and highest ages. However, by birth cohort analysis the blood lead levels declined monotonically with age. The joinpoint analysis indicated the inflection point of age 13-17 years and statistically significant differences in decline slopes before and after this age.

CONCLUSIONS

In this nationally representative study of the U.S. population, estimates of blood lead levels showed an overall decrease from 1999 to 2016. Blood lead levels are highest in childhood.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background

A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment.

Methods

We have designed and evaluated a bacterial biosensor expressing a luciferase reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans) containing the CH34 and pI258 plasmids of Staphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr biosensor and pGL3-luc/cad biosensor, that were based on the expression of luc+ and under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans.

Results

We found that the pGL3-luc/pbr biosensor may be used to measure lead concentrations between 1–100 μM in the presence of other metals, including zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal. The pGL3-luc/cad biosensor could detect lead concentrations between 10 nM to 10 μM.

Conclusions

This biosensor was found to be specific for measuring lead ions in both environmental and biological samples.

Main controlling factors and forecasting models of lead accumulation in earthworms based on low-level lead-contaminated soils

To explore the main controlling factors in soil and build a predictive model between the lead concentrations in earthworms (Pb_earthworm) and the soil physicochemical parameters, 13 soils with low level of lead contamination were used to conduct toxicity experiments using earthworms. The results indicated that a relatively high bioaccumulation factor appeared in the soils with low pH values. The lead concentrations between earthworms and soils after log transformation had a significantly positive correlation (R² = 0.46, P < 0.0001, n = 39). Stepwise multiple linear regression analysis derived a fitting empirical model between Pb_earthworm and the soil physicochemical properties: log(Pb_earthworm) = 0.96log(Pb_soil) - 0.74log(OC) - 0.22pH + 0.95, (R² = 0.66, n = 39). Furthermore, path analysis confirmed that the Pb concentrations in the soil (Pb_soil), soil pH, and soil organic carbon (OC) were the primary controlling factors of Pb_earthworm with high pathway parameters (0.71, - 0.51, and - 0.49, respectively). The predictive model based on Pb_earthworm in a nationwide range of soils with low-level lead contamination could provide a reference for the establishment of safety thresholds in Pb-contaminated soils from the perspective of soil-animal systems.

Folk prescription for treating rhinitis as a rare cause of childhood lead poisoning: a case series

Background

Folk prescriptions continue to be important sources of childhood lead poisoning. Nasal spray folk prescriptions for treating rhinitis has only been reported once previously as a cause of lead poisoning.

Case presentation

We identified three pediatric cases of severe lead poisoning caused by nasal spray folk medicines prescribed for treating rhinitis. The three patients had similar clinical manifestations including: severe abdominal pain, headache, pale appearance and fatigue. Liver function tests were abnormal. Blood lead levels (BLLs) of the three patients were 91 μg/dL, 91 μg/dL, and 105 μg/dL, respectively. After chelation BLLs decreased. The lead content of the three folk remedies as measured by inductively coupled plasma mass spectrometry (ICP-MS) were 14.8, 22.3, and 33.4%. All the symptoms resolved during a course of chelation therapy. There were no severe side effects of treatment.

Conclusions

Nasal spray folk prescriptions for treating rhinitis may contain extremely high bio-accessible lead content and are potential sources of lead poisoning. Clinicians should be alert to this possibility especially in those children presenting with multisystem symptoms.

Declines in adult blood lead levels in New York City compared with the United States, 2004-2014

OBJECTIVES

To assess changes in lead exposure in the New York City (NYC) adult population over a 10-year period and to contrast changes with national estimates, overall, and by socio-demographics and smoking status.

METHODS

We used measurements of blood lead levels (BLLs) from NYC resident adults who participated in the NYC Health and Nutrition Examination Surveys (HANES) in 2004 and 2013-2014. We compared estimates of geometric means (GM), 95th percentiles, and prevalence of BLL ≥ 5 µg/dL overall and by subgroups over time, with adults who participated in the National HANES (NHANES) 2001-2004 and 2011-2014.

RESULTS

The GM BLLs among NYC adults declined from 1.79 µg/dL in 2004 to 1.13 µg/dL in 2013-2014 (P < .0001). The declines over this period ranged from 30.1% to 43.2% across socio-demographic groups and smoking status (P < .0001 for all comparisons), and were slightly greater than declines observed nationally. The drop in prevalence of elevated BLLs (≥ 5 µg/dL) was also greater in NYC (4.8-0.5%), compared with NHANES (3.8-2.0%). By 2013-2014, NYC adults with lower annual family income (< $20,000) no longer had higher GM BLLs relative to those with higher incomes (≥ $75,000), a disparity improvement not observed nationally. Likewise, GM BLLs and 95th percentiles for non-Hispanic black adults in NYC were lower than GM BLLs for non-Hispanic white adults. Non-Hispanic Asian adults had the highest GM BLLs compared with other racial/ethnic groups, both in NYC in 2013-14 and nationally in 2011-2014 (1.37 µg/dL, P = .1048 and 1.22 µg/dL, P = .0004, respectively).

CONCLUSION

The lessening of disparity in lead exposure across income groups and decreasing exposure at the high end of the distribution among non-Hispanic black and Asian adults in NYC suggest that regulatory and outreach efforts have effectively targeted these higher exposure risk groups. However, Asian adults still had the highest average BLL, suggesting a need for enhanced outreach to this group. Local surveillance remains an important tool to monitor BLLs of local populations and to inform initiatives to reduce exposures in those at highest risk.

Lead: Tiny but Mighty Poison

The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.

A comparison of arsenic exposure in young children and home water arsenic in two rural West Texas communities

Background

In a previously conducted Health Impact Assessment of a well-water dependent southwest community, arsenic (As) levels greater than the EPA Maximum Contaminant Level (10 μg/L) were identified in home water samples. The goals of this study were to test whether children from the previously studied well-water dependent community (Community 1) had higher blood As levels than children from a demographically similar and geographically nearby community dependent on a municipal water supply (Community 2); to test whether home water As levels predicted child As blood levels; and to examine how child As blood levels changed over time.

Methods

This was an observational study of 252 children aged 4 to 12 years from two communities. Children were recruited through elementary schools and tested during the school day; 204 children participated in follow-up testing. Home water samples were collected according to U.S. Environmental Protection agency recommended procedures. Child heavy metal blood levels and home water sample heavy metal levels were analyzed using inductively coupled plasma mass spectrometry. General linear regression analysis was used to test the influence of community on child As levels, and to examine the contribution of home water As levels to child blood As levels.

Results

Arsenic was detectable in all children tested. Blood levels ranged from 0.09–2.61 μg/dL; approximately 31% of children tested at Time I (79/252) had blood As values above the current acceptable limit (1.2 μg/dL). Approximately 8% of household water samples (6/76) had As levels higher than 10 μg/L. Community did not predict child blood As levels; seasonal effects differed by Community. At Time II, child blood As levels were higher in Community 2 than in Community 1.

Conclusion

A large proportion of children in the communities tested had As exposure. Home water As levels did not predict child blood As levels. Fluctuating child blood As levels by season and over time suggested the contribution of multiple factors and the need for further studies.

Toxicants in folk remedies: implications of elevated blood lead in an American-born infant due to imported diaper powder

Though most childhood lead exposure in the USA results from ingestion of lead-based paint dust, non-paint sources are increasingly implicated. We present interdisciplinary findings from and policy implications of a case of elevated blood lead (13-18 mcg/dL, reference level <5 mcg/dL) in a 9-month-old infant, linked to a non-commercial Malaysian folk diaper powder. Analyses showed the powder contains 62 % lead by weight (primarily lead oxide) and elevated antimony [1000 parts per million (ppm)], arsenic (55 ppm), bismuth (110 ppm), and thallium (31 ppm). These metals are highly bioaccessible in simulated gastric fluids, but only slightly bioaccessible in simulated lung fluids and simulated urine, suggesting that the primary lead exposure routes were ingestion via hand-mouth transmission and ingestion of inhaled dusts cleared from the respiratory tract. Four weeks after discontinuing use of the powder, the infant's venous blood lead level was 8 mcg/dL. Unregulated, imported folk remedies can be a source of toxicant exposure. Additional research on import policy, product regulation, public health surveillance, and culturally sensitive risk communication is needed to develop efficacious risk reduction strategies in the USA. The more widespread use of contaminated folk remedies in the countries from which they originate is a substantial concern.

An Update on Childhood Lead Poisoning

Childhood lead poisoning is a multi-faceted, complex condition, which affects not only the child's health and well-being, but also the family's housing security, economic status, job security, and stress level. This review updates the emergency department clinician on the management of childhood lead poisoning. Infants and children are at higher risk than adults for lead exposure due to their smaller size and proportionately larger dose of ingested toxins, their proximity to ground dirt and indoor dust, their energy and curiosity, their oral exploratory and pica behaviors, their proportionately larger daily water and milk intake, and dietary preferences that differ markedly from those of adults. Pediatric health care providers working in the emergency department can provide medical management, as well as preventive counseling and guidance, to parents of children presenting with evidence of acute or chronic lead poisoning.

Lead poisoning in a 16-year-old girl: a case report and a review of the literature (CARE compliant)

BACKGROUND

Lead is a toxic element of the environment which leads to major complications once it enters the blood stream, affecting multiple organs and systems of the body.

METHODS

We present the case of a 16-year-old girl, diagnosed with lead poisoning after occupational exposure due to the fact that the girl was actively involved in the family's pottery business.History revealed that the girl participated in the process of pottery, her father was also diagnosed with lead poisoning 2 years before. The patient's personal history underlined that approximately 1 year ago she presented with severe abdominal pain, being diagnosed with acute appendicitis and she underwent appendectomy, but the pain persisted, thus due to family history of lead poisoning, the suspicion of saturnine colic rose, and she was diagnosed with lead poisoning. The main symptoms and signs were severe abdominal pain, vomiting, and arterial hypertension. The clinical evolution was favorable under symptomatic treatment and chelation therapy.

RESULTS

Lead toxicity is a life-threatening condition because of its severe acute and chronic complications. In children, there is no safe blood lead level, prevention methods are, therefore, very important in order to avoid toxic multiorganic effects of this metal.

CONCLUSION

Even though the diagnosis of lead poisoning remains difficult in children, it must also be taken into consideration by the clinician facing a child with gastrointestinal or neurological involvement.

Environmental and Occupational Lead Exposure Among Children in Cairo, Egypt: A Community-Based Cross-Sectional Study

The aim of this study was to assess childhood lead exposure in a representative sample of Cairo, and to investigate the possible risk factors and sources of exposure. This cross-sectional study was conducted from November 2014 through April 2015. The target population was children aged 6 to 18 years, recruited into 4 groups, garbage city, moderate-living standard area, urban and suburban schools, and workshops in the city of Cairo. Blood lead levels (BLLs) and hemoglobin (Hb) concentrations were measured. Also, potential local environmental sources were assessed for hazardous lead contamination. Analysis on 400 participants has been carried out. A total of 113 children had BLLs in the range 10 to 20 μg/dL. Smoking fathers, housing conditions, playing outdoors, and exposure to lead in residential areas were significantly correlated with high BLLs. The mean values of hemoglobin were inversely correlated with BLLs. Children involved in pottery workshops had the highest BLLs and the lowest Hb values with a mean of (43.3 μg/dL and 8.6 g/dL, respectively). The mean value of environmental lead in workshop areas exceeded the recommended levels. Also, those values measured in dust and paint samples of garbage city were significantly high. Moreover, the mean lead levels in the soil samples were significantly higher in urban schools (P = 0.03) than the suburban ones. Childhood lead poisoning accounts for a substantial burden in Egypt, which could be preventable. Development of national prevention programs including universal screening program should be designed to reduce incidence of lead toxicity among children.

Systemic Lead Toxicity

A 4-year-old girl with slow mentation had increasing knee tenderness and limping gait.

Neurological and Epigenetic Implications of Nutritional Deficiencies on Psychopathology: Conceptualization and Review of Evidence

In recent years, a role for epigenetic modifications in the pathophysiology of disease has received significant attention. Many studies are now beginning to explore the gene-environment interactions, which may mediate early-life exposure to risk factors, such as nutritional deficiencies and later development of behavioral problems in children and adults. In this paper, we review the current literature on the role of epigenetics in the development of psychopathology, with a specific focus on the potential for epigenetic modifications to link nutrition and brain development. We propose a conceptual framework whereby epigenetic modifications (e.g., DNA methylation) mediate the link between micro- and macro-nutrient deficiency early in life and brain dysfunction (e.g., structural aberration, neurotransmitter perturbation), which has been linked to development of behavior problems later on in life.

Lead toxicity: a review

Lead toxicity is an important environmental disease and its effects on the human body are devastating. There is almost no function in the human body which is not affected by lead toxicity. Though in countries like US and Canada the use of lead has been controlled up to a certain extent, it is still used vehemently in the developing countries. This is primarily because lead bears unique physical and chemical properties that make it suitable for a large number of applications for which humans have exploited its benefits from historical times and thus it has become a common environmental pollutant. Lead is highly persistent in the environment and because of its continuous use its levels rise in almost every country, posing serious threats. This article reviews the works listed in the literature with recent updates regarding the toxicity of lead. Focus is also on toxic effects of lead on the renal, reproductive and nervous system. Finally the techniques available for treating lead toxicity are presented with some recent updates.

Distribution of selected carcinogenic hydrocarbon and heavy metals in an oil-polluted agriculture zone

Owing to the importance of clean and fertile agricultural soil for the continued existence of man, this study investigated the concentrations of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs) and some heavy metals in soils and selected commonly consumed vegetables and tubers from oil-polluted active agricultural farmland in Gokana of Ogoniland, Rivers State, Nigeria. Samples from Umuchichi, Osisioma Local Government Area in Abia State, Nigeria, a non-oil-polluted area constituted the control. In test and control, up to 3,830 ± 19.6 mgkg(-1) dw and 6,950 ± 68.3 mgkg(-1) dw (exceeding DPR set limits) and 11.3 ± 0.04 mgkg(-1) dw and 186 ± 0.02 mgkg(-1) dw for TPH and PAHs, respectively, were recorded in test soil and plant samples, respectively. Among the metals studied (Pb, Cd, Cr, Mn, Fe and Zn), Pb and Cr uptake exceeded WHO set limits for crops in test samples. Combined sources of pollution were evident from our studies. Bitterleaf and Waterleaf could be tried as bioindicators owing to expressed contaminants uptake pattern.

The national trend of blood lead levels among Chinese children aged 0-18 years old, 1990-2012

We analyzed the epidemiological data during 1990-2012 that investigated the blood lead level (BLL) in the population aged 0-18 years old in China mainland and provided evidence of the benefits of implementing policies to prevent lead pollution based on the dynamic changes of BLL. Data were collected through databases including China Knowledge Resource Integrated Database (CNKI), CBM disc, Wanfang Data, Pubmed and Medline. The inclusion criteria were: 1. Epidemiological study in healthy population not included studies limited to specific patient; 2. Study subject was not the specific lead exposure population; 3. Sample size should be no less than 100 (for neonatal, no less than 50); 4. BLL detection was under strict quality control; and 5. Results should be presented as BLL (arithmetic mean level or geometric mean level). 62 articles were included in this study. All the surveys in these articles contained 189,352 subjects in 19 provinces, autonomous regions and municipalities. Linear regression analysis showed a significant decrease between 1990 and 2012 with an estimated regression coefficient of 3.05/year (SE=0.01, p<0.001). BLL gradually declined since early 21st century. Median levels of BLL among the three economic zones were 51.4 μg/L in the eastern zone, 52.72 μg/L in the central zone and 46.2 μg/L in the western zone respectively. Median BLLs in male and female population aged 0-18 years old of China were 48.8 μg/L and 46.1μg/L. Median levels of BLL among the different age ranges were 74.9 μg/L in newborn, 46.4 μg/L in 0 to 3 years old, 57.6 μg/L in 3 to 7 years old and 55.6 μg/L in above 7 years old respectively. In conclusion, the BLL in the Chinese population of 0-18 years old has gradually dropped in the past 10 years. The decline in temporal trend still remains under potential impacts of several factors such as economical level, gender and age difference. Although, China has made significant achievements in the control prevention of lead pollution, concerted efforts are still warranted to reduce children lead poisoning.

An investigation of outpatient children's blood lead level in Wuhan China

Objective

Blood lead levels (BLLs) and possible influencing factors in children in Wuhan China were investigated in order to understand current lead pollution exposure and provide a scientific basis for prevention and policy making.

Materials and Methods

BLL data were collected from 15,536 out-patients in Wuhan Children Hospital in 2012 full year. All of them were under 18 years of age (Mean ± SD: 4.32±3.2, 64.4% boys). The BLLs were measured by an atomic absorption spectrometry (BH2100).

Results

The geometric mean of BLLs for all the subjects was 44.75 µg/L (95%CI: 44.46 µg/L – 45.05 µg/L), much lower than that reported in previous studies. The prevalence of the elevated BLLs (≥ 100 µg/L) in the children tested was 2% in 2012 and the prevalence of BLLs (≥ 50 µg/L) was 44%. Age and sex could be possible influencing factors for BLLs in the children (p<0.001). In addition, the BLLs in different seasons were different (p<0.001).

Conclusions

These results demonstrate that BLLs have significantly decreased in children in Wuhan during recent years. However, we should continuously pay attention to lead pollution and emphasize that prevention is much more important than treatment for controlling children's BLLs.

A selective amperometric sensing platform for lead based on target-induced strand release

A novel strategy for selective and sensitive amperometric detection of lead ion (Pb(2+)) was proposed based on target-induced strand release. The underlying gold electrode was pre-modified with dendritic gold nanoparticles by direct electrodeposition to afford increased electrode surface area for immobilization of thiol group-containing capture DNA molecules. The hybridization of the capture DNA molecules with Pb(2+)-specific aptamer molecules to form a DNA duplex, into which methylene blue was intercalated, induced measurable electrochemical signal. Upon addition of Pb(2+), it could specifically bind to its aptamer to form Pb(2+)-stablized G-quadruplex and induce the aptamer strand to release from the electrode surface into solution, accompanied by the release of intercalated MB responsible for significant signal reduction. The fabricated biosensor showed a linear response to the logarithm of Pb(2+) concentration over the range of 1.0 × 10(-10) M to 1.0 × 10(-7) M with a detection limit of 7.5 × 10(-11) M. In addition, this strategy afforded an exquisite selectivity for Pb(2+) against other metal ions. The excellent sensitivity and selectivity show good potential for Pb(2+) detection in real environmental samples.

Pb tolerance and bioaccumulation by the mycelia of Flammulina velutipes in artificial enrichment medium

Mushrooms have the ability to accumulate high concentrations of heavy metals, which gives them potential for use as bioremediators of environmental contamination. The Pb(2+) tolerance and accumulation ability of living mycelia of Flammulina velutipes were studied in this work. Mycelial growth was inhibited when exposed to 1 mM Pb(2+). The colony diameter on solid medium decreased almost 10% compared with the control. Growth decreased almost 50% when the Pb(2+) concentration increased to 4 mM in the medium, with the colony diameter decreasing from 80 mm to 43.4 mm, and dry biomass production in liquid cultures decreasing from 9.23±0.55 to 4.27±0.28 g/L. Lead ions were efficiently accumulated in the mycelia. The amount of Pb(2+) in the mycelia increased with increasing Pb(2+) concentration in the medium, with the maximum concentration up to 707±91.4 mg/kg dry weight. We also show evidence that a large amount of the Pb(2+) was adsorbed to the mycelial surface, which may indicate that an exclusion mechanism is involved in Pb tolerance. These results demonstrate that F. velutipes could be useful as a remediator of heavy metal contamination because of the characteristics of high tolerance to Pb(2+) and efficient accumulation of Pb(2+) ions by the mycelia.

The use of feathers of birds of prey as indicators of metal pollution

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions.

Determination of lead in biological samples of children with different physiological consequences using cloud point extraction method

In present study, lead (Pb) level in biological samples of children with physiological disorders (liver, bone, and gastrointestinal; age ranged 1-10 years) have been assessed. For comparison purpose, age-matched healthy children were also selected. Cloud point extraction (CPE) was employed for preconcentration of Pb in acid-digested biological samples prior to its determination by flame atomic absorption spectrometry (FAAS). Dithizone (diphenylthiocarbazone) and nonionic surfactant Triton X-114 (TX-114) were used as complexing reagent and extractant, respectively. The effects of several experimental variables on proposed CPE were evaluated. Under the optimum experimental conditions, the observed detection limit (LOD) and the enhancement factor (EF) were 0.08 μg L(-1) and 53, respectively. Relative standard deviation (RSD) of 10 μg L(-1) Pb was 3.4 %. It was observed that children with liver-, bone-, and gastrointestinal-related disorders had three- to fourfold higher Pb level in blood and scalp hair samples.

Association of blood lead with calcium, iron, zinc and hemoglobin in children aged 0-7 years: a large population-based study

Lead exposure in children has received increasing attention from scientists and public health institutions worldwide. Deficiencies of nutritional essential metals can increase the hazard from lead exposure by enhancing absorption and toxicity of dietary lead. Lead, as a ubiquitous toxicity metal, may interact metabolically with nutritional essential metals. A large population-based study was conducted to investigate blood lead, calcium, iron, zinc and hemoglobin levels in healthy children aged 0-7 years. Based on the records, 158 (3.57 %) of 4,429 children had a blood lead levels (BLLs) ≥ 10 μg/dl, and 1,324 (30.30 %) children had a BLL ≥ 7 μg/dl. BLLs in children aged less than 3 years was lower than those in older children. BLLs had a negative correlation with blood calcium and iron level (r = -0.357 and r = -0.070, P < 0.01). Multiple logistic regression analysis also showed that BLLs had a negative correlation with blood calcium and iron. BLLs can be influenced by the status of some essential trace metals in children. Supplement of nutritional elements may help reduce lead absorption. Children with elevated BLLs (≥ 10 μg/dl) were controlled well in recent years in Chengdu. But the burden of reducing BLLs remains extremely arduous, which requires the joint efforts of both government agencies and the public.

A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations

Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport.

Toxicology in the ICU: part 3: natural toxins

This is the third article of a three-part series that reviews the care of poisoned patients in the ICU. This article focuses on natural toxins, such as heavy metals and those produced by plants, mushrooms, arthropods, and snakes. The first article discussed the general approach to the patient, including laboratory testing; the second article focused on specific toxic agents, grouped into categories.

Lessons learned on lead poisoning in children: one-hundred years on from Turner's declaration

There is significant emerging evidence showing life-long negative health, intellectual and socio-behavioural impacts as a result of childhood blood lead concentrations well below the widely used intervention level of 10 µg/dL. This issue raises serious health concerns for children in several Australian smelting and mining towns. Routine educational and home cleanliness advice to wet mop floors rather than to use a brush and pan to reduce lead exposure risks have been shown to have limited efficacy. This paper argues, as advocated 100 years ago by Queensland doctor Alfred Jefferis Turner, that childhood lead poisoning can only be mitigated via primary prevention and reduction of contaminants at source. Given that the effects of lead exposure are irreversible, there is a strong argument for the application of the precautionary principle to dealing with childhood lead exposure. There is a clear need to improve regulatory controls and emissions management to reduce environmental lead exposure risks.

Uncommon sources and some unsual manifestations of lead poisoning in a tropical developing country

Lead-containing cooking utensils, sometimes used in South Indian homes, and indigenous medications, widely used in India and increasingly in developed countries, may be responsible for lead intoxication in adults. We report chronic lead poisoning in five adult patients. Not all patients had abdominal colic, while dramatic weight loss, depression and encephalopathy were seen. Once recognized, lead poisoning is treatable and sometimes preventable. Response to chelation therapy with agents such as calcium ethylenediaminetetraacetate (CaEDTA) is impressive, although several courses of therapy may be necessary.

Study of lead level during pregnancy by application of synchrotron radiation micro XRF

In order to study the daily Pb absorption in fetus and to monitor the main Pb sources in prenatal fetus, we have investigated several cases of Pb distribution along the longitudinal axis of fetal hair. The changes of Pb levels in the pregnancy period, even the daily changes of Pb levels can be detected in the hair. Therefore, by analyzing the Pb distribution curves in the fetal hair and the living habits of their mothers, the main sources of Pb in the prenatal fetus can be evaluated. In our study, the main sources of Pb in the two cases of prenatal fetus studied here should be from the polluted aquatics.

Soil intervention as a strategy for lead exposure prevention: the New Orleans lead-safe childcare playground project

The feasibility of reducing children's exposure to lead (Pb) polluted soil in New Orleans is tested. Childcare centers (median = 48 children) are often located in former residences. The extent of soil Pb was determined by selecting centers in both the core and outlying areas. The initial 558 mg/kg median soil Pb (range 14-3692 mg/kg) decreased to median 4.1 mg/kg (range 2.2-26.1 mg/kg) after intervention with geotextile covered by 15 cm of river alluvium. Pb loading decreased from a median of 4887 μg/m(2) (454 μg/ft(2)) range 603-56650 μg/m(2) (56-5263 μg/ft(2)) to a median of 398 μg/m(2) (37 μg/ft(2)) range 86-980 μg/m(2) (8-91 μg/ft(2)). Multi-Response Permutation Procedures indicate similar (P-values = 0.160-0.231) soil Pb at childcare centers compared to soil Pb of nearby residential communities. At ∼$100 per child, soil Pb and surface loading were reduced within hours, advancing an upstream intervention conceptualization about Pb exposure prevention.

Practical guidelines for evaluating lead exposure in children with mental health conditions: molecular effects and clinical implications

Children in the United States are exhibiting extremely high levels of attentional and learning disabilities. Although lead has been eliminated from many industrial products, children continue to come into contact with it, such as in toys and cosmetics. Lead exposure occurs most commonly in poor, urban populations, and can exacerbate psychiatric disorders associated with stress. We present 1) an overview of lead exposure; 2) a detailed summary of current research on the molecular synergy of toxicity caused by lead and stress; 3) a review of human studies that appear to correlate with these molecular findings, including understanding nutrition, environmental enrichment, and caregiving as risk modifiers; and 4) a systematic approach for mental health practitioners in managing children presenting with multiple symptoms and risk factors for mental health conditions. In this article, we review some of the clinical and scientific challenges that relate to the assessment and treatment of children presenting for mental health care who may have potential lead exposure.

Encephalopathy from lead poisoning masquerading as a flu-like syndrome in an autistic child

Acute encephalopathy from childhood lead poisoning is fortunately rare. However, in pediatric patients with developmental disabilities and pica, there is a risk of lead exposure at a dose commensurate with encephalopathy, coupled with a risk of delayed diagnosis because of difficulty in distinguishing between baseline and altered behavior. We report here a 4-year old autistic boy who presented to the pediatrician's office with gastrointestinal symptoms and behavioral changes and was at first thought to have a viral syndrome. He returned 2 days later with a worsening illness; increasing pallor, vomiting, abdominal colic, and changes in consciousness were recognized in the emergency department as lead-induced anemia and encephalopathy, associated with a positive abdominal film for paint chips and a blood lead level equal to 216 microg/dL (10.43 micromol/L) (reference, <10 microg/dL or 0.483 micromol/L). As this case illustrates, prompt recognition is dependent on the skills and suspicions of an astute clinician, especially in the busy emergency department.

Environmental exposures and development

PURPOSE OF REVIEW

Summarize recent studies exploring the relationship between paternal and maternal environmental exposures to chemicals before, at the time of and after conception to adverse developmental outcomes including preterm birth, death, structural and functional abnormalities and growth restriction.

RECENT FINDINGS

Recent studies have demonstrated that human pregnancy and development are vulnerable to environmental exposures of the father and mother to chemical, biological and physical agents. Exposures associated with adverse developmental outcomes include air and water pollution, chemicals in foods, occupational exposures, agricultural chemicals, metals, persistent and volatile organics. Developmental endpoints which are linked with these exposures include growth restriction, functional abnormalities, structural abnormalities, preterm delivery and death. Despite this general understanding we still have incomplete knowledge concerning most exposures and the biological interactions responsible for impaired development and preterm delivery.

SUMMARY

Whereas single genes and individual chemical exposures are responsible for some instances of adverse pregnancy outcome or developmental disease, gene-environment interactions are responsible for the majority. These gene-environment interactions may occur in the father, mother, placenta or fetus, suggesting that critical attention be given to maternal and paternal exposures and gene expression as they relate to the mode of action of the putative developmental toxicant both prior to and during pregnancy.