Reducing Lead and Silica Dust Exposures in Small-Scale Mining in Northern Nigeria.

Purpose: 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. Occupational Knowledge International (OK International) and Doctors Without Borders/Médecins Sans Frontières (MSF) have formed a partnership to conduct a pilot project to introduce safer mining practices in selected communities. 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. Methods: 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. We measured reductions in total airborne lead and respirable silica dust levels. A total of 44 air samples were collected for airborne lead using NIOSH method 7082 and 29 air samples for respirable silica dust with NIOSH method 7500. Results: 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. Differences in geometric means between wet and dry ore processing methods were statistically significant for both airborne lead and respirable silica. Conclusions: 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. As silica dust is a significant risk factor for silicosis and tuberculosis (TB), this intervention could provide public health benefits to small-scale mining communities even in areas without significant lead concentrations in the ore. Significant reductions in respirable silica and lead exposures are feasible in low-resource, small-scale mining communities.

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.