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

Abstract

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.

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

“…Since remediation, new village residents and children born to mothers with low body burden are not experiencing high residential soil lead exposures (i.e., > 400 mg/kg). Similar reductions in other toxic metal concentrations (arsenic, cadmium, and mercury) were achieved simultaneously (Bartrem et al 2014). …”

“…Several cubic meters of contaminated waste were identified in shady locations and near water sources throughout the villages where crushing, grinding, drying, sluicing, and storage of ores took place. Also, dangerous concentrations of arsenic, cadmium, mercury and manganese were observed, and these metals would be removed with the lead during remediation (Bartrem et al 2014). …”

“…Common areas and residential compounds were assessed for lead and other metals in situ by modifying BHSS protocols for hand-held X-ray fluorescence (XRF) and by laboratory XRF of bulk and sieved samples of surface soils, dusts, and mining wastes (Bartrem et al 2014; TerraGraphics 2009; von Lindern et al 2011). Innov-X Alpha 4000 (Olympus), Innov-X (Olympus) Delta 4000, Innov-X (Olympus) DS 4000, and Niton XL3 (Thermo Fisher Scientific Inc.) models were used.…”

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

“…The Zamfara lead poisoning was termed as the worst lead poisoning epidemic in human history [54]. The health consequence of the Zamfara lead poisoning is reported in recent literature [55][56][57]. Despite the fact that one of the daughter nuclides of 210 Pb has been identified as a powerful alpha emitter that is used in radiation poisoning [58,59], till date, no study has considered the radio toxicity of the Zamfara lead poisoning.…”

Developmental Exposure to Lead

“…Indeed, significantly elevated blood lead levels are the norm for many children in countries that have not phased lead out of gasoline [12]. A notable tragedy has unfolded over the past several years in Nigeria, where activities related to gold mining have resulted in widespread lead exposures and what has been described as the worst outbreak of lead poisoning in modern history, killing hundreds of children [18][19][20][21]. A notable tragedy has unfolded over the past several years in Nigeria, where activities related to gold mining have resulted in widespread lead exposures and what has been described as the worst outbreak of lead poisoning in modern history, killing hundreds of children [18][19][20][21].…”