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

Plumlee GS, Durant JT, Morman SA, Neri A, Wolf RE, Dooyema CA, Hageman PL, Lowers HA, Fernette GL, Meeker GP, Benzel WM, Driscoll RL, Berry CJ, Crock JG, Goldstein HL, Adams M, Bartrem CL, Tirima S, Behbod B, von Lindern I, Brown MJ - Environ. Health Perspect. (2013)

Bottom Line: 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.Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways.Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats.

View Article: PubMed Central - PubMed

Affiliation: US Geological Survey, Denver, Colorado 80225, USA. gplumlee@usgs.gov

ABSTRACT

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.

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Related in: MedlinePlus

Total lead (Pb) concentrations (ppm mass basis; mg lead/kg solid) and simulated gastric fluid–leachable lead concentrations (ppm mass basis; calculated as (mg lead/kg leachate) × (100 kg leachate/1 kg solid)] in Zamfara samples. Each bar pair represents results for a single sample. Percentage of bioaccessible lead is listed above the paired bars for each sample, and was calculated by dividing the SGF-leachable concentration by the total concentration for the sample, and then multiplying by 100. Horizontal red line indicates U.S. EPA (2011a) RSSL for lead (400 ppm).
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f3: Total lead (Pb) concentrations (ppm mass basis; mg lead/kg solid) and simulated gastric fluid–leachable lead concentrations (ppm mass basis; calculated as (mg lead/kg leachate) × (100 kg leachate/1 kg solid)] in Zamfara samples. Each bar pair represents results for a single sample. Percentage of bioaccessible lead is listed above the paired bars for each sample, and was calculated by dividing the SGF-leachable concentration by the total concentration for the sample, and then multiplying by 100. Horizontal red line indicates U.S. EPA (2011a) RSSL for lead (400 ppm).

Mentions: Lead was generally highly gastric bioaccessible, with 39–66% of the total lead solubilized in an hour from 9 of 12 samples analyzed (Table 3, Figure 3). The highest percent bioaccessibility was measured in a less heavily contaminated village outskirt soil. Manganese was also generally quite gastric bioaccessible, with 6–43% of the total manganese solubilized. However, mercury (< 0.9% of total), arsenic (< 2.1% of total), and antimony (< 1.4% of the total) were not appreciably gastric bioaccessible (Table 3).


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

Plumlee GS, Durant JT, Morman SA, Neri A, Wolf RE, Dooyema CA, Hageman PL, Lowers HA, Fernette GL, Meeker GP, Benzel WM, Driscoll RL, Berry CJ, Crock JG, Goldstein HL, Adams M, Bartrem CL, Tirima S, Behbod B, von Lindern I, Brown MJ - Environ. Health Perspect. (2013)

Total lead (Pb) concentrations (ppm mass basis; mg lead/kg solid) and simulated gastric fluid–leachable lead concentrations (ppm mass basis; calculated as (mg lead/kg leachate) × (100 kg leachate/1 kg solid)] in Zamfara samples. Each bar pair represents results for a single sample. Percentage of bioaccessible lead is listed above the paired bars for each sample, and was calculated by dividing the SGF-leachable concentration by the total concentration for the sample, and then multiplying by 100. Horizontal red line indicates U.S. EPA (2011a) RSSL for lead (400 ppm).
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672918&req=5

f3: Total lead (Pb) concentrations (ppm mass basis; mg lead/kg solid) and simulated gastric fluid–leachable lead concentrations (ppm mass basis; calculated as (mg lead/kg leachate) × (100 kg leachate/1 kg solid)] in Zamfara samples. Each bar pair represents results for a single sample. Percentage of bioaccessible lead is listed above the paired bars for each sample, and was calculated by dividing the SGF-leachable concentration by the total concentration for the sample, and then multiplying by 100. Horizontal red line indicates U.S. EPA (2011a) RSSL for lead (400 ppm).
Mentions: Lead was generally highly gastric bioaccessible, with 39–66% of the total lead solubilized in an hour from 9 of 12 samples analyzed (Table 3, Figure 3). The highest percent bioaccessibility was measured in a less heavily contaminated village outskirt soil. Manganese was also generally quite gastric bioaccessible, with 6–43% of the total manganese solubilized. However, mercury (< 0.9% of total), arsenic (< 2.1% of total), and antimony (< 1.4% of the total) were not appreciably gastric bioaccessible (Table 3).

Bottom Line: 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.Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways.Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats.

View Article: PubMed Central - PubMed

Affiliation: US Geological Survey, Denver, Colorado 80225, USA. gplumlee@usgs.gov

ABSTRACT

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.

Show MeSH
Related in: MedlinePlus