Tirima S, Bartrem C, von Lindern I, von Braun M, Lind D, Anka S, Abdullahi A (2017). Food Contamination as a Pathway for Lead Exposure in Children During the 2010-2013 Lead Poisoning Epidemic in Zamfara, Nigeria. Journal of Environmental Sciences, Advanced Publication.
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 0.32 mg/kg and 0.85 mg/kg dry weight, respectively. Age-specific food lead intake ranged from 7 to 78 μg/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.
Tirima S, Bartrem C, von Lindern I, von Braun M, Lind D, Anka S, Abdullahi A (2016). Environmental Remediation to Address Childhood Lead Poisoning Epidemic due to Artisanal Gold Mining in Zamfara, Nigeria. Environmental Health Perspectives, 124(9) 1471-1478
Background: From 2010-2013, 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 more than 400 children. Socio-economic, logistic, and security challenges required remediation and medical protocols within the context of local resources, labor practices, and cultural traditions. Objectives: To implement emergency environmental remediation to abate exposures to 17,000 lead poisoned villagers, to facilitate chelation treatment of children five years old and younger, and to establish local technical capacity and lead health advocacy programs to prevent future disasters. Methods: US hazardous waste removal protocols were modified to accommodate local agricultural practices. Remediation was conducted over four 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 27,000m3 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 (≤25mg/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 149µg/dL to 15µg/dL over the four-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.
von Lindern I, Spalinger S, Stifelman ML, Stanek LW, Bartrem C (2016). Estimating Children’s Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho. Environmental Health Perspectives, 124(9) 1462-1470
Background: Soil/dust ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are largely based on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. Objectives: The objective was to estimate site-specific soil/dust ingestion rates through re-evaluation of the lead absorption dose-response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. Methods: The U.S. Environmental Protection Agency (USEPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, bioavailable lead from these sources was related to children’s blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the USEPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Results: Absolute soil and house dust bioavailability averaged 33% (SD ±4%) and 28% (SD ±6%), respectively. Estimated BHSS age-specific soil/dust ingestion rates are 86-94 mg/day for 6 month to 2 year old children and 51-67 mg/day for 2-9 year old children. Conclusions: Soil/dust ingestion rate estimates for 1-9 year old children at the BHSS are lower than those commonly used in human health risk assessment. A substantial component of children’s exposure comes from sources beyond the immediate home environment.
Bartrem C, Tirima S, von Lindern I, von Braun M, Worrell MC, Mohammad Anka S, Abdullahi A, Moller G (2014). Unknown risk: co-exposure to lead and other heavy metals among children living in small-scale mining communities in Zamfara State, Nigeria. International Journal of Environmental Health Research, 24(4), 304–319
The lead poisoning crisis in Zamfara State, Northern Nigeria has been called the worst such case in modern history and it presents unique challenges for risk assessment and management of co-exposure to multiple heavy metals. More than 400 children have died in Zamfara as a result of ongoing lead intoxication since early in 2010. A review of the common toxic endpoints of the major heavy metals advances analysis of co-exposures and their common pathologies. Environmental contamination in Bagega village, examined by X-ray fluorescence of soils, includes lead, mercury, cadmium, arsenic and manganese. Co-exposure risk is explored by scoring common toxic endpoints and hazard indices to calculate a common pathology hazard risk ranking of Pb > As > Hg >> Cd > Mn. Zamfara presents an extreme picture of both lead and multiple heavy metal mortality and morbidity, but similar situations have become increasingly prevalent worldwide.
von Braun MC, von Lindern IH, Khristoforova NK, Kachur AH, Yelpatyevsky PV, Elpatyevskaya VP, Spalinger SM (2002). Environmental Lead Contamination in the Rudnaya Pristan – Dalnegorsk Mining and Smelter District, Russian Far East. Environmental Research, 88(3), 164–173
A preliminary survey of a remote mining and smelting region of the Russian Far East (RFE) indicates significant soil lead contamination and a high probability of childhood lead poisoning. Lead concentrations in residential gardens (476-4310 mg/kg, Gmean=1626 mg/kg) and in roadside soils (2020-22900 mg/kg, Gmean=4420 mg/kg) exceed USEPA guidance for remediation. Preliminary biokinetic estimates of mean blood levels suggest that preschool children are at significant risk of lead poisoning from soil/dust ingestion with levels predicted to average 13-27 microg/dl. Samples of other pathways, such as air, water, paint, interior dust, and garden produce, and pediatric and occupational blood lead levels are needed. An assessment of the industry's ability to improve emissions controls and materials handling should also be undertaken. Global lessons in remediating contamination problems and preventing childhood lead poisoning must be applied in innovative ways to meet the logistical, social, and economic challenges in the RFE.
An ongoing health crisis across a large area of Northern Nigeria has resulted in hundreds of deaths and thousands of cases of lead poisoning from artisanal small-scale gold mining. The primary objective was to reduce lead exposures among artisanal small-scale miners and minimize take home exposures by reducing dust contamination on clothing and body surfaces. Personal air samples were collected from miners and ore processors before and after the introduction of wet spray misting in mine processing activities to crush and grind gold ore. Low-cost interventions to convert dry ore processing to wet methods with spray misting were effective at reducing arithmetic mean airborne lead levels by 95%. Mean airborne respirable silica (quartz) was reduced by 80% following the introduction of wet spray misting. This pilot project has been successful in working cooperatively with miners to provide them with the necessary information and tools to reduce exposures in mining and processing, and minimize off-site contamination. Significant reductions in respirable silica and lead exposures are feasible in low-resource, small-scale mining communities.
Pollution is the largest environmental cause of disease and premature death in the world today. Diseases caused by pollution were responsible for an estimated 9 million premature deaths in 2015—16% of all deaths worldwide—three times more deaths than from AIDS, tuberculosis, and malaria combined and 15 times more than from all wars and other forms of violence. In the most severely affected countries, pollution-related disease is responsible for more than one death in four.
Background: From the early 1900s to the 1950s, Yakima Valley orchards were commonly treated with lead arsenate (LA) insecticides. Lead (Pb) and arsenic (As) soil contamination has been identified on former orchard lands throughout Central Washington and pose a threat to human health and the environment. Objectives: The levels of Pb and As in soil and interior dust at participating childcare centers in the Upper Yakima Valley (Yakima County), Washington were sampled to explore exposure potential for young children. Methods: Childcare center soils were collected from two soil depths, homogenized, and analyzed in bulk by a field-portable X-ray fluorescence spectrometer (XRF). Interior dust wipes samples were collected from at least two locations in each facility. All soil samples >250 mg/kg Pb and/or >20 As mg/kg were sieved to 250 μm, tested by XRF a second time, and analyzed via acid digestion and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Results: Bulk and sieved XRF results, as well as ICP-MS to XRF results were strongly correlated. Maximum Pb and As XRF results indicated that 4 (21%) and 8 (42%) of the 19 childcare centers surveyed exceeded the regulatory standard for Pb and As, respectively. Historic land use was significantly associated with elevated Pb and As levels. Interior dust loadings were below United States Environmental Protection Agency (EPA) guidelines. Conclusions: Childcare centers are areas of intensive use for children and when coupled with potential residential exposure in their homes, the total daily exposure is a potential hazard to children.
Kachur A N, Arzhanova VS, Yelpatyevsky PV, von Braun MC, von Lindern IH (2003). Environmental conditions in the Rudnaya River watershed—a compilation of Soviet and post-Soviet era sampling around a lead smelter in the Russian Far East. Science of the Total Environment, 303(1), 171–185
Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.
Twenty-Third Granville H. Sewell Distinguished Lecture in Environmental Health Sciences