Association of blood lead level with neurological features in 972 children affected by an acute severe lead poisoning outbreak in Zamfara State, northern Nigeria

Lead speciation in body tissues, gastrointestinal contents, and feces of lead-exposed wild rats (Rattus rattus)

The toxic effects of lead (Pb) are an ongoing concern for which research continues to seek a solution. In Pb-contaminated areas, Pb concentrations in the environment and organisms are quantified to assess the degree of contamination. Understanding organismal uptake of Pb and its behavior in the body requires distinguishing Pb chemical species. We used Pb L3-edge X-ray absorption near-edge structure (XANES) to study the distribution of Pb species in body tissues, digestive tract contents, and feces of wild rats (Rattus rattus) collected from a heavily Pb-contaminated mining area in Zambia. Freeze-drying improved the XANES spectrum quality by approximately 10 μg-Pb/g-dry through concentrating the Pb without changing its chemical state from its wet state. We successfully identified and analyzed the Pb species in seven different tissues (bone, muscle, liver, kidney, spleen, lung, and brain), three different digestive-tract contents (stomach, small intestine, and colon), and feces from three wild rats. We described chemical-form-based details of Pb uptake and distribution that are common among rats, such as the increased Pb binding with thiol groups through the digestive system, distribution of mobile Pb to hematopoietic organs and vascular-related tissues, and Pb binding to thiol groups, especially in the liver and brain.

Investigating outbreaks of initially unknown aetiology in complex settings: findings and recommendations from 10 case studies

BACKGROUND

Outbreaks of unknown aetiology in complex settings pose challenges and there is little information about investigation methods. We reviewed investigations into such outbreaks to identify methods favouring or impeding identification of the cause.

METHODS

We used two approaches: reviewing scientific literature and soliciting key informants. Case studies were developed through interviews with people involved and triangulated with documents available from the time of the investigation.

RESULTS

Ten outbreaks in African or Asian countries within the period 2007-2017 were selected. The cause was identified in seven, of which two had an unclear mode of transmission, and in three, neither origin nor transmission mode was identified. Four events were caused by infectious agents and three by chemical poisoning. Despite differences in the outbreaks, similar obstacles were noted: incomplete or delayed description of patients, comorbidities confounding clinical pictures and case definitions wrongly attributed. Repeated rounds of data collection and laboratory investigations were common and there was limited capacity to ship samples.

DISCUSSION

It was not possible to define activities that led to prompt identification of the cause in the case studies selected. Based on the observations, we conclude that basing case definitions on precise medical observations, implementing initial comprehensive data collection, including environmental, social and behavioural information; and involving local informants could save precious time and hasten implementation of control measures.

Neonatal blood lead concentration predicts medium term lead-related outcomes in children ≤5 years old with congenital lead poisoning: A retrospective cohort study in Northern Nigeria

Mother-to-child-transmission of lead via the placenta is known to result in congenital lead toxicity. Between 2010 and 2021, Médecins Sans Frontières and other stakeholders responded to a severe lead poisoning outbreak related to artisanal gold mining in Northern Nigeria. Extensive environmental remediation occurred following outbreak identification; source control efforts are ongoing within the community. We aimed to describe the prevalence of congenital lead poisoning in this cohort and analyse the association between neonatal blood lead concentration (BLC) and medium-term lead-related outcomes during the study period. Children enrolled in the lead poisoning programme between July 2010 and 25 January 2018 who had a screening BLC at ≤4 weeks of age were included. For time-to-event analysis, medium-term outcomes were classified as lead-related (death from lead encephalopathy, and/or met chelation threshold) and non-lead-related (non-lead-related death, on programme no chelation, exit from programme without chelation). Cox regression analysis and ROC analysis were performed. 1468 children were included. All-cause mortality 2.3%; geometric mean neonatal BLC 13.7 μg/dL; 'lead-related death or treatment' 19.3%. For every doubling in neonatal BLC, there was an almost 8-fold increase in adjusted hazard ratio (HR) for the composite lead-related outcome (p<0.001). A neonatal BLC ≥ 15.0 μg/dL had 95% sensitivity for identifying children who went on to have the composite outcome (with specificity 67%; positive likelihood ratio 2.86). Congenital lead poisoning predicts ongoing exposure in this population, even after environmental remediation. This suggests a complex, early, multidisciplinary approach to source control and exposure management is required when elevated neonatal BLC is observed in lead poisoning clusters in low-and-middle-income contexts.

Adaptive neuro-fuzzy inference system (ANFIS) and multiple linear regression (MLR) modelling of Cu, Cd, and Pb adsorption onto tropical soils

Soils interact in many ways with metal ions thereby modifying their mobility, phase distribution, plant availability, speciation, and so on. The most prominent of such interactions is sorption. In this study, we investigated the sorption of Pb, Cd, and Cu in five natural soils of Nigerian origin. A relatively sparsely used method of modelling soil-metal ion adsorption, i.e. adaptive neuro-fuzzy inference system (ANFIS), was applied comparatively with multiple linear regression (MLR) models. The isotherms were well described by Freundlich and Langmuir equations (R² ≥ 0.95) and the kinetics by nonlinear two-stage kinetic model, TSKM (R² ≥ 0.81). Based on the values delivered by the Langmuir equation, the maximum adsorption capacities (Q_m*) were found to be in the ranges 10,000-20,000, 12,500-50,000, and 4929-35,037 µmol kg^-1 for Cd, Cu, and Pb, respectively. The study revealed significant correlations between Q_m* and routinely determined soil parameters such as soil organic carbon (C_org), cation exchange capacity (CEC), amorphous Fe and Mn oxides, and percentage clay content. These soil parameters, combined with operational variables (i.e. solution/soil pH, initial metal concentration (C_o), and temperature), were used as input vectors in ANFIS and MLR models to predict the adsorption capacities (Q_e) of the soil-metal ion systems. A total of 255 different ANFIS and 255 different MLR architectures/models were developed and compared based on three performance metrics: MAE (mean absolute error), RMSE (root mean square errors), and R² (coefficient of determination). The best ANFIS returned MAE_test 0.134, RMSE_test 0.164, and R²_test 0.76, while the best MLR returned MAE_test 0.158, RMSE_test 0.199, and R²_test 0.66, indicating the predictive advantage of ANFIS over MLR. Thus, ANFIS can fairly accurately predict the adsorption capacity and/or distribution coefficient of a soil-metal ion system a priori. Nevertheless, more investigation is required to further confirm the robustness/generalisation of the proposed ANFIS.

Investigation and monitoring of heavy metal poisoning

Historically, heavy metal measurement and interpretation has been a highly specialised area performed only in a handful of centres within the UK. However, recent years have seen a move to more local testing due to the repatriation of referred work into pathology networks and the increased availability of inductively coupled plasma mass spectrometry technology. While management of significant poisoning is still overseen by tertiary care poisoning specialists, management of milder cases may be undertaken locally.Non-specialist clinical scientists and clinicians need to know when heavy metal testing is appropriate, which samples are required (and any specific requirements around collection) and how to interpret and act on the results.This Best Practice article provides guidance on the investigation and monitoring of the toxic elements most frequently encountered in general medical practice; lead, mercury and arsenic. It is intended as a reference guide for the non-specialist and as a comprehensive summary for clinical toxicologists and clinical scientists.

Reducing disease and death from Artisanal and Small-Scale Mining (ASM) - the urgent need for responsible mining in the context of growing global demand for minerals and metals for climate change mitigation

Artisanal and small-scale mining (ASM) takes place under extreme conditions with a lack of occupational health and safety. As the demand for metals is increasing due in part to their extensive use in 'green technologies' for climate change mitigation, the negative environmental and occupational consequences of mining practices are disproportionately felt in low- and middle-income countries. The Collegium Ramazzini statement on ASM presents updated information on its neglected health hazards that include multiple toxic hazards, most notably mercury, lead, cyanide, arsenic, cadmium, and cobalt, as well as physical hazards, most notably airborne dust and noise, and the high risk of infectious diseases. These hazards affect both miners and mining communities as working and living spaces are rarely separated. The impact on children and women is often severe, including hazardous exposures during the child-bearing age and pregnancies, and the risk of child labor. We suggest strategies for the mitigation of these hazards and classify those according to primordial, primary, secondary, and tertiary prevention. Further, we identify knowledge gaps and issue recommendations for international, national, and local governments, metal purchasers, and employers are given. With this statement, the Collegium Ramazzini calls for the extension of efforts to minimize all hazards that confront ASM miners and their families.

Lead poisoning with encephalic and neuropathic involvement in a child: case report

Lead is a toxic substance in our environment that affects adults and children of all socioeconomic backgrounds, lead poisoning is one of the most common exposures that can cause inter alia significant neurological and functional damage in humans. Children are particularly vulnerable because of the effects of the toxicity on their developing nervous systems with potentially irreversible consequences. We report a case of severe lead poisoning encephalo-neuropathy in a 3-year-old girl, admitted for progressive paraplegia, swallowing disorders, and aphasia. A multitude of investigations undertaken could not explain her atypic symptoms, so anamnesis was redone in the sense of a toxic origin, we found a notion of pica, and a traditional herbalist father, so probably consumption of medications based on traditional medicine products. A venous blood lead level (BLL) was extremely elevated at 176.4 μg/l. The child was treated with an oral chelator succimer (SUCCICAPTAL). During the two following months in the intensive care unit, the child showed progressive respiratory distress and worsening signs of the nervous system. Despite treatment and the use of lead chelators, the patient died due to septic shock. Lead is highly toxic even at very low exposure levels, at high levels of exposure, it can damage the reproductive organs, immune system, liver and kidneys. in children, it can affect neurocognitive and behavioral development that could be irreversible. Peripheral and central nervous system damage should be considered as a possible manifestation of lead poisoning.

Exploring factors influencing patient mortality and loss to follow-up in two paediatric hospital wards in Zamfara, North-West Nigeria, 2016-2018

INTRODUCTION

Child mortality has been linked to infectious diseases, malnutrition and lack of access to essential health services. We investigated possible predictors for death and patients lost to follow up (LTFU) for paediatric patients at the inpatient department (IPD) and inpatient therapeutic feeding centre (ITFC) of the Anka General Hospital (AGH), Zamfara State, Nigeria, to inform best practices at the hospital.

METHODS

We conducted a retrospective cohort review study using routinely collected data of all patient admissions to the IPD and ITFC with known hospital exit status between 2016 and 2018. Unadjusted and adjusted rate ratios (aRR) and respective 95% confidence intervals (95% CI) were calculated using Poisson regression to estimate the association between the exposure variables and mortality as well as LTFU.

RESULTS

The mortality rate in IPD was 22% lower in 2018 compared to 2016 (aRR 0.78; 95% CI 0.66-0.93) and 70% lower for patients coming from lead-affected villages compared to patients from other villages (aRR 0.30; 95% CI 0.19-0.48). The mortality rate for ITFC patients was 41% higher during rainy season (aRR 1.41; 95% CI 1.2-1.6). LTFU rates in ITFC increased in 2017 and 2018 when compared to 2016 (aRR 1.6; 95% CI 1.2-2.0 and aRR 1.4; 95% CI 1.1-1.8) and patients in ITFC had 2.5 times higher LTFU rates when coming from a lead-affected village.

CONCLUSIONS

Our data contributes clearer understanding of the situation in the paediatric wards in AGH in Nigeria, but identifying specific predictors for the multifaceted nature of mortality and LTFU is challenging. Mortality in paediatric patients in IPD of AGH improved during the study period, which is likely linked to better awareness of the hospital, but still remains high. Access to healthcare due to seasonal restrictions contributes to mortalities due to late presentation. Increased awareness of and easier access to healthcare, such as for patients living in lead-affected villages, which are still benefiting from an MSF lead poisoning intervention, decreases mortalities, but increases LTFU. We recommend targeted case audits and qualitative studies to better understand the role of health-seeking behaviour, and social and traditional factors in the use of formal healthcare in this part of Nigeria and potentially similar settings in other countries.

Comparison of knowledge of occupational hazards of lead exposure and blood lead estimation among roadside and organized panel beaters in Enugu metropolis, Nigeria

INTRODUCTION

occupational practices continuously exposes workers to hazards of lead. This study aimed to compare the knowledge of occupational hazards associated with lead exposure, and blood lead estimation among roadside and organized panel beaters in Enugu metropolis, Nigeria.

METHODS

this was a cross-sectional study. Multistage sampling method was used to select 428 panel beaters in Enugu metropolis. Samples were analyzed using Atomic Absorption Spectrometer at 283.3 wavelengths. Data were entered and analyzed using Statistical Package for Social Science 20. Comparative analysis were done using chi - square, T-test, Mann-Whitney U-test, Kruskal-Wallis test, logistic regression and level of significance was set at 5%.

RESULTS

the majority of respondents on both roadside (59.8%) and organized (73.4%) sectors had poor knowledge of hazards of lead exposure. The difference was significant using χ² (P<0.05). The median blood lead levels were 3.0µg|dl and 16.0µg|dl for roadside and organized panel beaters respectively. The difference was significant with Mann-Whitney U test (P<0.001). The prevalence of elevated blood lead at 10µg|dl were 36.9% (roadside sector) and 64.5% (organized sector). The duration of working hours (OR = 4.34, CI = 1.729 - 10.338) was found to be the predictor of elevated blood lead levels.

CONCLUSION

there were general poor knowledge of hazards of lead exposure and high prevalence of elevated lead levels which were more among organized panel beaters. Advocacy on standard organizational structures that support improved occupational health practices is needed and routine outreach by research institutions for health education and safety training.

Blood Lead Levels and Subsequence Risk of Malaria in the African Population: A Systematic Review and Meta-Analysis

Previous epidemiological studies showed that blood lead level (BLL) was associated with malaria infection and severity. Therefore, the present study aimed to qualitatively and quantitatively synthesize the evidence on the association between BLL and risk of malaria infection and severity using the systematic review and meta-analysis approach. Potentially relevant studies were identified from three databases using a combination of search terms. The quality of the included studies was assessed using the checklist for the cross-sectional studies developed by the Joanna Briggs Institute. The qualitative synthesis of the risk or odds of malaria infection in patients with BLL was performed as the outcome of each included study could not be pooled. The pooled mean BLL and prevalence of malaria infection of the included studies was estimated using a random-effect model. The heterogeneity of the outcomes among the included studies was assessed using the Cochran Q test and I² statistics. The subgroup analysis of the study sites and participants was performed to explore the source(s) of heterogeneity of the outcomes. Publication bias was assessed in the case of more than 10 studies used for pooling of the same outcome. Among 114 potentially relevant studies identified from the databases, 6 eligible studies were included for qualitative and quantitative syntheses. The results showed that the pooled mean BLLs were 7.33 μg/dL in children (95% confidence interval (95%CI), 4.08–10.58; I², 98.2%), 7.94 μg/dL in children with BLL > 45 mg/dL before chelation (95%CI, 7.87–8.01), 7.41 μg/dL in infants (95%CI, 7.34–7.48 μg/dL), 9.20 μg/dL in children with malaria (95%CI, 9.16–9.24 μg/ dL), and 36.37 μg/dL in pregnant women (95%CI, 34.43–38.31 μg/dL). The prevalence rates of malaria among participants (2381 participants, 803 malaria-positive patients) were 53% in children (95%CI, 50–57%; I², 99.8%), 24% in children with BLL > 45 mg/dL before chelation (95%CI, 21–27%), 12% in infants (95%CI, 8–18%), and 21% in pregnant women (95%CI, 18–26%). The subgroup analysis of countries demonstrated that the prevalence rates of malaria among participants was 17% in Benin (95%CI, 13–21%; I², 98.8%) and 36% in Nigeria (95%CI, 10–63%; I², 99.4%). BLL associated with decreased risk of malaria was demonstrated by two studies conducted in Benin and Nigeria, while BLL associated with increased risk of malaria was demonstrated by a study conducted in Nigeria. BLL was associated with the risk of severe malaria, involving severe neurological features and severe anemia. In conclusion, the present systematic review and meta-analysis determined the current status of the studies on BLL and risk of malaria in African countries. Further studies are needed to investigate the impact of BLL on patients with malaria to help the clinician determine the risk of severity, such as the development of neurological features or severe anemia, among patients exposed to lead.

Urgent Need for a Comprehensive Public Health Response to Artisanal Small-Scale Mining

Informal sector mining is a growing enterprise in countries around the world providing livelihood to >40 million self-employed miners. The use of mercury in gold processing has been the sole focus of most research and public health interventions in artisanal mining. Few programs work to improve health among communities mining other commodities including sand, aggregates, quartz, lead, gemstones, coal and other materials. Although mercury is a major environmental challenge in countries with extensive gold mining, artisanal miners are also exposed to silica dust, metals and other safety hazards. The available evidence regarding hazardous exposures among self-employed miners suggests that the public health implications are much broader. There is a growing body of evidence linking exposures to silica dust to tuberculosis and other lung diseases among artisanal miners. Studies have also documented exposures to lead and other metals including arsenic, cadmium, cobalt and chromium in informal mining communities. Silica-dust exposures are higher in artisanal mining than levels reported in large industrial mining. There is ample evidence that artisanal miners are experiencing health impacts not just from mercury but also from exposures to noise, silica dust and metals. Practical, low-cost solutions have been pilot tested and shown to reduce respirable silica dust and metal exposures among miners and ore processors. Governments, development agencies and global health funders should invest in comprehensive public health programs to respond to these needs.

Environmental health situation in Nigeria: current status and future needs

Environmental health-related risks are becoming a primary concern in Nigeria, with diverse environmental problems such as air pollution, water pollution, oil spillage, deforestation, desertification, erosion, and flooding (due to inadequate drainage systems) caused mostly by anthropogenic activities. This paper reviews the pre-existing and current environmental health problems, proffer future research and needs, policy needs, and recommendations necessary to mitigate Nigeria's environmental health situation. Data from the Institute of Health Metric and Evaluation on Global Burden of Disease (GBD) was used to ascertain the causes of Death and Disability-adjusted Life Years (DALYs) in Nigeria from 2007-2017 and published literatures where reviewed. According to the world health data report, most of the highest-ranked causes of DALYs in Nigeria are related to environmental risk factors. The lower respiratory infection associated with air pollution has advanced from the 4th in 2007 to the highest ranked cause of death in 2017. Other predominant causes of death associated with environmental risk factors include chronic respiratory diseases, cardiovascular diseases, enteric infections, diarrheal diseases, communicable, maternal, neonatal, and nutritional disease, which has resulted in approximately 800 thousand deaths and 26 million people living with DALYs per annum in Nigeria. Major environmental risk factors include household air pollution, ambient air pollution, water, sanitation, and hygiene (WaSH), which shows a prolonged but progressive decline. In contrast, ambient particulate matter pollution, ambient ozone pollution, and lead exposure show a steady rise associated with death and DALYs in Nigeria, indicating a significant concern in an environmental health-related risk situation. Sustaining a healthy environment is critical in improving the quality of life and the span of a healthy life. Therefore, environmentally sustainable development policies and practices should be essential to the population and policymakers for a healthy life.

Community Engagement and Outreach Programs for Lead Prevention in Mississippi

The objective of the project was to encourage health promotion through education, outreach, and community-based training. The people attending health fairs (n = 467), community events (n = 469), and Kindergarten classes (n = 241) were the study participants. Hands-on training was offered at homebuilding retail stores (n = 25). U.S. Department of Housing and Urban Development (HUD)'s online visual training was given to realtors (n = 220), and inspectors, contractors, and Do-It-Yourself (DIY) workers (n = 75). Training workshops were attended by home-buyers and rental home owners at the Neighborhood Association Meetings (n = 91). The impact of training was evaluated by pre- and posttests. Nearly, 90% of the participants (n = 25) reported the hands-on training was useful. At posttest after the HUD online training, 59.4%, 67.9%, 65.1% of the participants (n = 220) identified soil, car batteries, and paint as sources of lead in the environment, respectively. Nearly 70% identified lead as a poison in the environment while 77.5% and 47.2% demonstrated two behaviors which help prevent lead poisoning. A total of 62.3%, 48.1%, and 58.5%, at posttest identified three complications or illnesses-behavioral, physical, and psychological, respectively. The home owners are required to get permission from the City for housing repair. In coordination with the federally funded housing repair or lead abatement programs, the trained inspectors are authorized to certify the renovation or repair works. These outreach activities were successful in improving the knowledge of the community people on lead poisoning prevention.

Burn to kill: Wood ash a silent killer in Africa

Aside the emissions, burning of wood in traditional cookstoves (TCs) also generates substantial amount of ash containing hazardous pollutants such as polycyclic aromatic hydrocarbons (PAHs) and toxic metals. But, their concentrations in the ash, particularly in Africa where over 70% of the population utilize TCs, remain unknown. Here, we determined concentrations of sixteen PAHs and eleven heavy metals in ashes from twelve different African TCs, comprising six three-stone fires (TSFs) and six built-in-place cookstoves (BIPCs), burning common African wood species under real world situation. For each TC, ash samples were collected for six consecutive days (Monday-Saturday), and a total of seventy-two daily samples were collected from January-June 2019. Ash yields were measured gravimetrically, and concentrations of the pollutants were determined following standard analytical protocols. The results were used alongside secondary data (annual fuelwood consumption, African fuelwood densities, population proportion using fuelwood and surface human population density) to estimate annual tonnage, exposure potential and risk to health in Africa, using Monte Carlo simulation technique. The ash yields from all TCs studied exceeded 1% on dry weight basis, indicating that ash is a major waste by-product of wood combustion in TCs. TSFs produced more ash (5.7 ± 0.7%) than BIPCs (3.4 ± 1.0%). Concentrations of As, Cd, Hg and Pb in ashes were significantly higher (α = 0.05) for TSFs than BIPCs. In contrast, concentrations of PAHs were higher in ashes from BIPCs than TSFs. Assuming ash consumption rates range from 250 to 500 mg/day for young children weighing 10 to 30 kg, the upper dose (μg/kg-day) of Pb (0.2-3.9) or Σ₁₆PAHs (0.02-0.34), for instance, surpasses the 0.3 μg/kg-day of Pb or PAH recognized as causing adverse effects in children, indicating a concern. The top five countries with the highest annual tonnage or exposure potential to toxic pollutants are Nigeria>Ethiopia>DR-Congo>Tanzania>Uganda, or Rwanda>Burundi>Uganda>Nigeria>Guinea-Bissau, respectively.

Probabilistic estimates of prenatal lead exposure at 195 toxic hotspots in low- and middle-income countries

BACKGROUND

Prior estimates of pediatric lead-related disease burden in low- and middle-income countries (LMICs) used population estimates of maternal blood lead levels (BLLs). This approach may underestimate fetal BLLs by not considering potentially high prenatal lead exposure from toxic hotspots. OBJECTIVES: We developed a probabilistic approach to using the Adult Lead Methodology (ALM) to estimate fetal BLLs from prenatal exposure to lead-contaminated soil at hotspots in the Toxic Site Identification Program (TSIP).

METHODS

We created distributions for each ALM parameter using published literature and extracted soil lead measurements from the TSIP database. Each iteration of the probabilistic ALM randomly selected values from the input distributions to generate a site-specific fetal BLL estimate. For each site, we ran 5000 model iterations, producing a site-specific fetal BLL distribution.

RESULTS

195 TSIP sites, in 33 LMICs, met our study inclusion criteria; an estimated 820,000 women of childbearing age are at risk for lead exposure at these sites. The predicted geometric means (GM) for site-specific fetal BLLs ranged from 3.3 μg/dL to 534 μg/dL, and 98% of sites had estimated GM fetal BLLs >5 μg/dL, the current reference level of the United States Centers for Disease Control and Prevention (CDC), while 11 sites had estimated GM fetal BLLs above the CDC chelation threshold of 45 μg/dL.

DISCUSSION

The TSIP soil lead data and this probabilistic approach to the ALM show that pregnant women living near TSIP sites may have BLLs that put their fetus at risk for neurologic damage and other sequelae, underscoring the need for interventions to reduce lead exposure at toxic hotspots.

Environmental Health Research in Africa: Important Progress and Promising Opportunities

The World Health Organization in 2016 estimated that over 20% of the global disease burden and deaths were attributed to modifiable environmental factors. However, data clearly characterizing the impact of environmental exposures and health endpoints in African populations is limited. To describe recent progress and identify important research gaps, we reviewed literature on environmental health research in African populations over the last decade, as well as research incorporating both genomic and environmental factors. We queried PubMed for peer-reviewed research articles, reviews, or books examining environmental exposures and health outcomes in human populations in Africa. Searches utilized medical subheading (MeSH) terms for environmental exposure categories listed in the March 2018 US National Report on Human Exposure to Environmental Chemicals, which includes chemicals with worldwide distributions. Our search strategy retrieved 540 relevant publications, with studies evaluating health impacts of ambient air pollution (n=105), indoor air pollution (n = 166), heavy metals (n = 130), pesticides (n = 95), dietary mold (n = 61), indoor mold (n = 9), per- and polyfluoroalkyl substances (PFASs, n = 0), electronic waste (n = 9), environmental phenols (n = 4), flame retardants (n = 8), and phthalates (n = 3), where publications could belong to more than one exposure category. Only 23 publications characterized both environmental and genomic risk factors. Cardiovascular and respiratory health endpoints impacted by air pollution were comparable to observations in other countries. Air pollution exposures unique to Africa and some other resource limited settings were dust and specific occupational exposures. Literature describing harmful health effects of metals, pesticides, and dietary mold represented a context unique to Africa. Studies of exposures to phthalates, PFASs, phenols, and flame retardants were very limited. These results underscore the need for further focus on current and emerging environmental and chemical health risks as well as better integration of genomic and environmental factors in African research studies. Environmental exposures with distinct routes of exposure, unique co-exposures and co-morbidities, combined with the extensive genomic diversity in Africa may lead to the identification of novel mechanisms underlying complex disease and promising potential for translation to global public health.

Is the Concentration of Cadmium, Lead, Mercury, and Selenium Related to Preterm Birth?

Environmental pollution and exposure of people to heavy metals cause many bad obstetric outcomes. Our aim is to demonstrate the role of cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in preterm labor etiology with a case-control study. In this study, between November 2017 and April 2018, preterm delivery mothers and term delivery mothers were compared in Çorum, Turkey. All deliveries were performed with cesarean sections and there were 30 mothers in the control group and 20 in the study group. The maternal blood, maternal urine, umbilical cord blood, and heavy metal levels in the amnion fluid in both groups were studied. Graphite furnace atomic absorption spectrometry was used to determine the blood concentration of Cd, Pb, Hg, and Se. We found lower levels of selenium in blood and urine of preterm delivery mothers and umbilical cord and amnion fluids of preterm infants (p < 0.01). We found a statistically significant positive correlation at selenium levels between mother's blood and umbilical cord blood (r (50) = 0.896, p < 0.001) and between maternal urine and amniotic fluid (r (50) = 0.841, p < 0.001). We have not found a similar correlation between mother and fetus of other metals (p > 0.05). We found that selenium levels were lower in mothers who were preterm birth in the light of the data in our study. We could not determine the positive or negative correlation of Cd, Pb, and Hg levels in blood, urine, and amniotic fluid samples with preterm birth.

Declining blood lead levels among small-scale miners participating in a safer mining pilot programme in Nigeria

OBJECTIVES

Our objective was to monitor blood lead levels (BLLs) of miners and ore processors participating in a pilot programme to reduce lead poisoning and take-home exposures from artisanal small-scale gold mining. A medical surveillance programme was established to assess exposures as new methods aimed at reducing lead exposures from ore were introduced in a community in Nigeria where children experienced substantial lead-related morbidity and mortality.

METHODS

Extensive outreach and education were offered to miners, and investments were made to adopt wet methods to reduce exposures during mining and processing. We conducted medical surveillance, including a physical exam and repeated blood lead testing, for 61 miners selected from among several hundred who participated in the safer mining pilot programme and consented to testing. Venous blood lead concentrations were analysed using the LeadCare II device at approximately 3-month intervals over a period of 19 months.

RESULTS

Overall geometric mean (GM) BLLs decreased by 32% from 31.6 to 21.5 µg/dL during the 19-month project. Women had a somewhat lower reduction in GM BLLs (23%) compared with men (36%). There was a statistically significant reduction in log BLLs from baseline to the final test taken by each participant (p<0.001).

CONCLUSIONS

The observed reductions in GM BLLs during the pilot intervention among this representative group of miners and ore processors demonstrated the effectiveness of the safer mining programme in this community. Such measures are feasible, cost-effective and can greatly improve health outcomes in mining communities.

A Challenge between Central Nervous System Infection and Lead Toxicity: Opioid Case Reports from Iran

Although lead pollution has long been known as a cause of poisoning, it has remained a challenge to reliably diagnose it due to its common symptoms in various diseases. In this article, we report two cases of acute loss of consciousness due to the ingestion of opium-contaminated with lead. The reported cases share patterns of symptoms similar to meningitis and encephalitis which are usual etiology for the loss of consciousness. Lead poisoning is not a usual etiology for loss of consciousness and is considered in cases of occupational or environmental exposure. These reported cases showed a pattern similar to meningitis and encephalitis, but due to the unusual manifestations during their admission and coexistence with gastrointestinal symptoms, we were led to consider poisoning as the cause of consciousness loss. Lead poisoning often goes unrecognized due to a low index of suspicion, but it may turn out to be fatal. Therefore, it should be considered in the differential diagnosis of any neurobehavioral deficits in substance abusers.

Targeting the Iron-Response Elements of the mRNAs for the Alzheimer's Amyloid Precursor Protein and Ferritin to Treat Acute Lead and Manganese Neurotoxicity

The therapeutic value of inhibiting translation of the amyloid precursor protein (APP) offers the possibility to reduce neurotoxic amyloid formation, particularly in cases of familial Alzheimer’s disease (AD) caused by APP gene duplications (Dup–APP) and in aging Down syndrome individuals. APP mRNA translation inhibitors such as the anticholinesterase phenserine, and high throughput screened molecules, selectively inhibited the uniquely folded iron-response element (IRE) sequences in the 5’untranslated region (5’UTR) of APP mRNA and this class of drug continues to be tested in a clinical trial as an anti-amyloid treatment for AD. By contrast, in younger age groups, APP expression is not associated with amyloidosis, instead it acts solely as a neuroprotectant while facilitating cellular ferroportin-dependent iron efflux. We have reported that the environmental metallotoxins Lead (Pb) and manganese (Mn) cause neuronal death by interfering with IRE dependent translation of APP and ferritin. The loss of these iron homeostatic neuroprotectants thereby caused an embargo of iron (Fe) export from neurons as associated with excess unstored intracellular iron and the formation of toxic reactive oxidative species (ROS). We propose that APP 5’UTR directed translation activators can be employed therapeutically to protect neurons exposed to high acute Pb and/or Mn exposure. Certainly, high potency APP translation activators, exemplified by the Food and Drug Administration (FDA) pre-approved M1 muscarinic agonist AF102B and high throughput-screened APP 5’UTR translation activators, are available for drug development to treat acute toxicity caused by Pb/Mn exposure to neurons. We conclude that APP translation activators can be predicted to prevent acute metal toxicity to neurons by a mechanism related to the 5’UTR specific yohimbine which binds and targets the canonical IRE RNA stem loop as an H-ferritin translation activator.

Food contamination as a pathway for lead exposure in children during the 2010-2013 lead poisoning epidemic in Zamfara, Nigeria

In 2010, an estimated 400 to 500 children died of acute lead poisoning associated with artisanal gold mining in Zamfara, Nigeria. Processing of gold ores containing up to 10% lead within residential compounds put residents, especially children, at the highest risk. Principal routes of exposure were incidental ingestion and inhalation of contaminated soil and dusts. Several Nigerian and international health organizations collaborated to reduce lead exposures through environmental remediation and medical treatment. The contribution of contaminated food to total lead exposure was assessed during the environmental health response. Objectives of this investigation were to assess the influence of cultural/dietary habits on lead exposure pathways and estimate the contribution of contaminated food to children's blood lead levels (BLLs). A survey of village dietary practices and staple food lead content was conducted to determine dietary composition, caloric intakes, and lead intake. Potential blood lead increments were estimated using bio-kinetic modeling techniques. Most dietary lead exposure was associated with contamination of staple cereal grains and legumes during post-harvest processing and preparation in contaminated homes. Average post-harvest and processed cereal grain lead levels were 0.32mg/kg and 0.85mg/kg dry weight, respectively. Age-specific food lead intake ranged from 7 to 78μg/day. Lead ingestion and absorption were likely aggravated by the dusty environment, fasting between meals, and nutritional deficiencies. Contamination of staple cereal grains by highly bioavailable pulverized ores could account for as much as 11%-34% of children's BLLs during the epidemic, and were a continuing source after residential soil remediation until stored grain inventories were exhausted.

Current progress on understanding the impact of mercury on human health

Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012

BACKGROUND

In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities.

OBJECTIVES

The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children.

METHODS

A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages.

RESULTS

17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child's age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics.

CONCLUSIONS

Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children's BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures.

PATIENT CONSENT

Obtained.

ETHICS APPROVAL

The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria.

COMPETING INTERESTS

The authors declare no competing financial interests.

Environmental Remediation to Address Childhood Lead Poisoning Epidemic due to Artisanal Gold Mining in Zamfara, Nigeria

BACKGROUND

From 2010 through 2013, integrated health and environmental responses addressed an unprecedented epidemic lead poisoning in Zamfara State, northern Nigeria. Artisanal gold mining caused widespread contamination resulting in the deaths of > 400 children. Socioeconomic, logistic, and security challenges required remediation and medical protocols within the context of local resources, labor practices, and cultural traditions.

OBJECTIVES

Our aim was to implement emergency environmental remediation to abate exposures to 17,000 lead poisoned villagers, to facilitate chelation treatment of children ≤ 5 years old, and to establish local technical capacity and lead health advocacy programs to prevent future disasters.

METHODS

U.S. hazardous waste removal protocols were modified to accommodate local agricultural practices. Remediation was conducted over 4 years in three phases, progressing from an emergency response by international personnel to comprehensive cleanup funded and accomplished by the Nigerian government.

RESULTS

More than 27,000 m3 of contaminated soils and mining waste were removed from 820 residences and ore processing areas in eight villages, largely by hand labor, and disposed in constructed landfills. Excavated areas were capped with clean soils (≤ 25 mg/kg lead), decreasing soil lead concentrations by 89%, and 2,349 children received chelation treatment. Pre-chelation geometric mean blood lead levels for children ≤ 5 years old decreased from 149 μg/dL to 15 μg/dL over the 4-year remedial program.

CONCLUSIONS

The unprecedented outbreak and response demonstrate that, given sufficient political will and modest investment, the world's most challenging environmental health crises can be addressed by adapting proven response protocols to the capabilities of host countries.

CITATION

Tirima S, Bartrem C, von Lindern I, von Braun M, Lind D, Anka SM, Abdullahi A. 2016. Environmental remediation to address childhood lead poisoning epidemic due to artisanal gold mining in Zamfara, Nigeria. Environ Health Perspect 124:1471-1478; http://dx.doi.org/10.1289/ehp.1510145.

Is Prenatal Lead Exposure a Concern in Infancy? What Is the Evidence?

BACKGROUND

Exposure to unhealthy and unsafe environments cause 1 in 4 deaths in childhood each year. Early exposure to lead beginning prenatally and continuing throughout childhood is one of the mechanisms associated with unhealthy and unsafe environments, particularly in industrial countries and urban communities. Lead is a known heavy metal that crosses the placenta and blood-brain barrier depositing in fetal tissues.

PURPOSE

The purpose of this integrative review was to determine which maternal-fetal dyads were at high risk for elevated umbilical cord lead (Pb) levels and to examine the consequences associated with elevated umbilical cord Pb levels.

SEARCH STRATEGY

PubMed was searched to obtain English language publications from 2005 to March 2015 for studies examining the effects of prenatal lead exposure on infant outcomes using key terms "lead" combined with "infant." A total of 17 articles were retained for analysis.

FINDINGS

Infants with elevated umbilical cord blood lead levels were associated with maternal demographic factors and country of origin. Maternal-specific exposure to lead products prior to or during pregnancy was associated with elevated umbilical cord blood lead levels. The consequences of prenatal lead exposure to the infant at birth anthropometrically were mixed. The evidence on neurological consequences of prenatal exposure to lead appears to reflect changes in cognitive impairment; however, it needs further study.

IMPLICATIONS FOR PRACTICE

The major recommendation is primary prevention of lead exposure across the life span. Implementation of policies that reduce the availability of leaded products to reduce leaded products, especially ones aimed at children and women of childbearing age.

IMPLICATIONS FOR RESEARCH

Research needs to be focused in 2 directions: (1) prevention of lead exposure during pregnancy and (2) prevention of lead leaching from bones for all women of childbearing age.

Health and ecological hazards due to natural radioactivity in soil from mining areas of Nasarawa State, Nigeria

Nasarawa State is located in north central Nigeria and it is known as Nigeria's home of solid minerals. It is endowed with barite, copper, zinc, tantalite and granite. Continuous releases of mining waste and tailings into the biosphere may result in a build-up of radionuclides in air, water and soil. This work therefore aims to measure the activity concentration levels of primordial radionuclides in the soil/sediment samples collected from selected mines of the mining areas of Nasarawa State. The paper also assesses the radiological and radio ecological impacts of mining activities on the residents of mining areas and their environment. The activity concentrations of primordial radionuclides ((226)Ra, (232)Th and (40)K) in the surface soils/sediment samples were determined using sodium iodide-thallium gamma spectroscopy. Seven major mines were considered with 21 samples taken from each of the mines for radiochemistry analysis. The human health hazard assessment was conducted using regulatory methodologies set by the United Nations Scientific Committee on the Effects of Atomic Radiation, while the radio ecological impact assessment was conducted using the ERICA tool v. 1.2. The result shows that the activity concentrations of (40)K in the water ways of the Akiri copper and the Azara barite mines are 60 and 67% higher than the world average value for (40)K, respectively. In all mines, the annual effective dose rates (mSv y(-1)) were less than unity, and a maximum annual gonadal dose of 0.58 mSv y(-1) is received at the Akiri copper mine, which is almost twice the world average value for gonadal dose. The external hazard indices for all the mines were less than unity. Our results also show that mollusc-gastropod, insect larvae, mollusc-bivalve and zooplankton are the freshwater biotas with the highest dose rates ranging from 5 to 7 µGy h(-1). These higher dose rates could be associated with zinc and copper mining at Abuni and Akiri, respectively. The most exposed terrestrial reference organisms are lichen and bryophytes. In all cases, the radio ecological risks are not likely to be discernible. This paper presents a pioneer data for ecological risk from ionizing contaminants due to mining activity in Nasarawa State, Nigeria. Its methodology could be adopted for future work on radioecology of mining.

Description of 3,180 courses of chelation with dimercaptosuccinic acid in children ≤ 5 y with severe lead poisoning in Zamfara, Northern Nigeria: a retrospective analysis of programme data

BACKGROUND

In 2010, Médecins Sans Frontières (MSF) discovered extensive lead poisoning impacting several thousand children in rural northern Nigeria. An estimated 400 fatalities had occurred over 3 mo. The US Centers for Disease Control and Prevention (CDC) confirmed widespread contamination from lead-rich ore being processed for gold, and environmental management was begun. MSF commenced a medical management programme that included treatment with the oral chelating agent 2,3-dimercaptosuccinic acid (DMSA, succimer). Here we describe and evaluate the changes in venous blood lead level (VBLL) associated with DMSA treatment in the largest cohort of children ≤ 5 y of age with severe paediatric lead intoxication reported to date to our knowledge.

METHODS AND FINDINGS

In a retrospective analysis of programme data, we describe change in VBLL after DMSA treatment courses in a cohort of 1,156 children ≤ 5 y of age who underwent between one and 15 courses of chelation treatment. Courses of DMSA of 19 or 28 d duration administered to children with VBLL ≥ 45 µg/dl were included. Impact of DMSA was calculated as end-course VBLL as a percentage of pre-course VBLL (ECP). Mixed model regression with nested random effects was used to evaluate the relative associations of covariates with ECP. Of 3,180 treatment courses administered, 36% and 6% of courses commenced with VBLL ≥ 80 µg/dl and ≥ 120 µg/dl, respectively. Overall mean ECP was 74.5% (95% CI 69.7%-79.7%); among 159 inpatient courses, ECP was 47.7% (95% CI 39.7%-57.3%). ECP after 19-d courses (n = 2,262) was lower in older children, first-ever courses, courses with a longer interval since a previous course, courses with more directly observed doses, and courses with higher pre-course VBLLs. Low haemoglobin was associated with higher ECP. Twenty children aged ≤ 5 y who commenced chelation died during the period studied, with lead poisoning a primary factor in six deaths. Monitoring of alanine transaminase (ALT), creatinine, and full blood count revealed moderate ALT elevation in <2.5% of courses. No clinically severe adverse drug effects were observed, and no laboratory findings required discontinuation of treatment. Limitations include that this was a retrospective analysis of clinical data, and unmeasured variables related to environmental exposures could not be accounted for.

CONCLUSIONS

Oral DMSA was a pharmacodynamically effective chelating agent for the treatment of severe childhood lead poisoning in a resource-limited setting. Re-exposure to lead, despite efforts to remediate the environment, and non-adherence may have influenced the impact of outpatient treatment. Please see later in the article for the Editors' Summary.