Climate Change, Conflict, and Resource Extraction: Analyses of Nigerian Artisanal Mining Communities and Ominous Global Trends.

Background: The 2010 lead poisoning outbreak that claimed the lives of more than 400 children in artisanal gold mining villages in Zamfara, Nigeria is the tragic result of high gold prices, a geologic anomaly, and processing of ores in residential areas. Today, these villages face a growing crisis related to conflict and climate change. While the situation in Zamfara is unparalleled in many ways, the interactions between climate change, conflict, and mining consistently overlap a global scale. The scope of this analysis extends beyond the Nigerian crisis. Objectives: Understanding the complexities of challenges faced in Zamfara provides insight into how these issues impact vulnerable communities globally, and which strategies should be considered to solve this wicked problem. Methods: Analysis of the relationships between climate change, conflict, and mining in Zamfara and globally via literature review and examination of current events in the Sahel region. Findings: Supporting healthy artisanal mining communities, as was prioritized in Zamfara, must be a focus of environmental, health, and mineral management policies. This includes the consideration of multiple environmental health challenges, the protection of vulnerable groups, government-supported formalization programs, and meaningful involvement of local leadership in developing, implementing, and sustaining intervention strategies to enshrine ASM as a poverty reduction, climate change adaptation strategy. Conclusions: Rapidly rising metal prices and demand will continue to fuel environmental health crises associated with mining. Given Africa's growing role in the global mineral economy and the massive number of subsistence communities who will continue to be impacted by climate change, strategies that support responsible artisanal mining are both a necessity for preventing future health crises and an opportunity for promoting regional stability and peace.

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.

Estimating Children's Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho.

BACKGROUND: Soil/dust ingestion rates are important variables in assessing children's health risks in contaminated environments. Current estimates are based largely 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 reevaluation 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 (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources 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 U.S. EPA 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- to 9-year-old children. CONCLUSIONS: Soil/dust ingestion rate estimates for 1- to 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. CITATION: 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. Environ Health Perspect 124:1462-1470; http://dx.doi.org/10.1289/ehp.1510144.

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.

Unknown risk: co-exposure to lead and other heavy metals among children living in small-scale mining communities in Zamfara State, Nigeria.

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.

Linking geological and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria.

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.

Northern Idaho house dust and soil lead levels compared to the Bunker Hill Superfund Site.

House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized. The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations, and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations and loading rates.

Seasonal variations of lead concentration and loading rates in residential house dust in northern Idaho.

Although lead hazards to humans have been known since ancient times and many regulatory actions and lead risk reductions have been achieved over the past century, lead contamination and exposure remain significant problems worldwide. The focus of this study was to investigate whether residential house dust lead concentrations and lead and dust loading rates in non-contaminated or "background" communities in northern Idaho are significantly affected by seasonal variations. House dust samples were obtained from 34 houses in five towns of northern Idaho from March to November 1999. There was evidence of significant seasonality of lead concentration in house dust in some towns, but no evidence in other towns. Because of the high variability between the towns and small sample sizes, it was difficult to make firm conclusions about seasonal patterns observed in house dust lead levels. A linear relationship between precipitation rates and dust loading rates was detected.

The influence of soil remediation on lead in house dust.

Lead in house dust has long been recognized as a principal source of excess lead absorption among children at the Bunker Hill Superfund Site (BHSS) in northern Idaho. House dust lead concentration from homeowner's vacuum cleaner bags has been monitored since the epidemic of childhood lead poisoning in 1974. Geometric mean house dust lead concentrations decreased from >10000 mg/kg in 1974 to approximately 4000 mg/kg in 1975, in response to air pollution control initiatives at the defective primary lead smelter. After smelter closure, 1983 mean dust lead concentrations were near 3000 mg/kg and were most dependent on soil sources. Following emergency soil removals from public areas and roadsides and fugitive dust control efforts in the mid-1980s, house dust lead decreased by approximately 40-60% to 1200-1500 mg/kg. In 1992, a cleanup goal of 500 mg/kg dust lead community average, with no individual home exceeding 1000 mg/kg, was adopted. This goal was to be achieved by a combination of contaminated soil removals and fugitive dust control efforts throughout the 21 square mile BHSS. Continual reductions in house dust lead concentrations have been noted throughout the residential area soil cleanup. Geometric mean house dust lead concentrations averaged approximately 500-600 mg/kg from 1996 to 1999 and dropped below 500 mg/kg in 2000. Analysis of these data indicates that approximately 20% of the variance in dust lead concentrations is attributed to yard, neighborhood, and community soil lead concentrations. Since 1996, dust lead concentrations and dust and lead loading rates have also been measured by dust mats placed at entryways into the homes. Neighborhood soil lead concentrations, household hygiene, the number of adults living in the home, and the number of hours a child spends outdoors in summer explain approximately 26% of the variance in mat dust lead loading rates. It is estimated that post-remedial house dust lead concentrations will stabilize at 400-500 mg/kg, as compared to approximately 200 mg/kg in socio-economically similar background communities; the difference possibly attributed to residual soil concentrations (3-6 times background), recontamination of rights-of-way, tracking of non-residential mining district soils and dusts, fugitive dusts associated with the remediation, and residual structural or carpet dusts.

Assessing remedial effectiveness through the blood lead:soil/dust lead relationship at the Bunker Hill Superfund Site in the Silver Valley of Idaho.

The 21 square mile Bunker Hill Superfund Site in northern Idaho includes several thousand acres of contaminated hillsides and floodplain, a 365-acre abandoned lead/zinc smelter and is home to more than 7000 people in 5 residential communities. Childhood lead poisoning was epidemic in the 1970s with >75% of children exceeding 40 microg/dl blood lead. Health response activities have been ongoing for three decades. In 1991, a blood lead goal of 95% of children with levels less than 10 microg/dl was adopted. The cleanup strategy, based on biokinetic pathways models, was to reduce house dust lead exposure through elimination of soil-borne sources. An interim health intervention program, that included monitoring blood lead and exposures levels, was instituted to reduce exposures through parental education during the cleanup. In 1989 and 2001, 56% and 3% of children, respectively, exceeded the blood lead criteria. More than 4000 paired blood lead/environmental exposure observations were collected during this period. Several analyses of these data were accomplished. Slope factors derived for the relationship between blood lead, soil and dust concentrations are age-dependent and similar to literature reported values. Repeat measures analysis assessing year to year changes found that the remediation effort (without intervention) had approximately a 7.5 microg/dl effect in reducing a 2-year-old child's mean blood lead level over the course of the last ten years. Those receiving intervention had an additional 2-15 microg/dl decrease. Structural equations models indicate that from 40 to 50% of the blood lead absorbed from soils and dusts is through house dust with approximately 30% directly from community-wide soils and 30% from the home yard and immediate neighborhood. Both mean blood lead levels and percent of children to exceed 10 microg/dl have paralleled soil/dust lead intake rates estimated from the pathways model. Application of the IEUBK model for lead indicates that recommended USEPA default parameters overestimate mean blood lead levels, although the magnitude of over-prediction is diminished in recent years. Application of the site-specific model, using the soil and dust partitions suggested in the pathways model and an effective bioavailability of 18%, accurately predicts mean blood lead levels and percent of children to exceed 10 microg/dl throughout the 11-year cleanup period. This reduced response rate application of the IEUBK is consistent with the analysis used to originally develop the cleanup criteria and indicates the blood lead goal will be achieved.

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.

The Rudnaya River valley in the Russian Far East contains a rich reserve of lead, zinc and boron and has been mined for nearly 100 years. Environmental contamination related to the area's mines and lead smelter was studied for over 30 years during the Soviet era, by members of the Pacific Geographic Institute (PGI). Due to government restrictions, much of the sampling focused on contamination of the river, the air, forests, vegetation, agricultural products and soil. Source-specific samples, such as stack emissions from the smelter, and blood lead levels from the residents and smelter workers could not be obtained or were classified as State secrets. However, the data do describe the extent and severity of the environmental contamination and related public health concerns. Water discharged from the smelter averages 2900 m(3)/day (containing 100 kg of lead (Pb) and 20 kg of arsenic (As)) and leachate from area mine dumps and other industrial processes contaminates the Rudnaya River. Annual air emissions include 85 tonnes of particulates (containing 50 tonnes of Pb and 0.5 tonnes of As) and 250000 m(3) of gases high in sulfur dioxide (SO(2)), carbon monoxide (CO) and carbon dioxide (CO(2)). Vegetative stress is severe and much of this area is denuded. Pb and other metals in agricultural products suggest local produce may be dangerous for human consumption, although it is a major food source for the community. Public and occupational health indicators of basophilic stippling, respiratory disease and hair lead levels further suggest the severity of the problem. Although, descriptions of complete methodologies and procedures are often lacking, these data describe how sampling was conducted during the Soviet era and document a site with severe heavy metals contamination, especially lead, and the likelihood of related public health problems. They are relevant today as investigators employ state-of-the-art-sampling techniques and explore cleanup options under a new governmental system and challenging economic times. In the post-Soviet era, a Russian/US team sampled area soils and dusts and confirmed the severity of the environmental problems using commonly employed sampling and analysis techniques. Lead concentrations in residential gardens (476-4310 mg/kg, Gx=1626 mg/kg) and in roadside soils (2020-22900 mg/kg, Gx=4420 mg/kg) exceed USEPA guidance for remediation. Preliminary biokinetic estimates of mean blood levels (average 13-27 microg/dl) suggest pre-school children are at significant risk of lead poisoning from soil/dust ingestion. Today, the PGI, in cooperation with the industrial owners and the local health and environmental authorities, is attempting to establish long-term monitoring and pollution abatement within the constraints of their difficult economic situation.

Environmental lead contamination in the Rudnaya Pristan--Dalnegorsk mining and smelter district, Russian far East.

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.