**2. The place of occurrence of the lead poisoning crisis in Zamfara state**

In early 2010, the first presumed clue to environmental pollution (though apparently unclear to the local residents) began to emerge in the region. The report indicated a gradual reduction in numbers and subsequently, complete disappearance of duck population from the gold mining areas, which later became manifest throughout the region. These manifestations have been termed as the *Sentinels* (warning signs) of environmental hazards [6]. In March 2010, Medecins Sans Frontieres (MSF-Holland) that is, Doctors without borders discovered an unprecedented epidemic of lead poisoning in the region (Zamfara State) first in three Local Government Areas namely, Anka, Bukkuyum and Maru. An estimated 400 to 500 children were reported to have died from lead absorption, associated with the artisanal gold mining and processing in the area [7]. Investigations of other villages in the region revealed that lead poisoning was widespread in the State. Thousands of children had dangerous levels of lead in their blood and hundreds of children and animals had died of lead poisoning. It has been reported to be the largest known outbreak of lead poisoning in history [5].

High lead concentrations from unsafe artisanal gold mining and processing practices continued to cause lead poisoning mortality in younger children and morbidity in older populations [8]. The primary pathway of exposure for young children is through soil ingestion. Consequently, even if the exposure to lead had to stop now, the children already having lead poisoning would require years of expensive medical treatment [9]. Investigation reports on groundwater pollution in the area have shown that lead pollution remained confined to areas (wells and ponds) where mining and processing of gold from lead ore had taken place and had not spread through the groundwater aquifer [2]. In some drinking wells, concentrations of lead 10 to 15 times greater than the WHO recommended limit of 10 μg/L have been found. Also, reports on surface water sources (ponds, rivers and lakes) in the mining areas showed higher

## *Lead Poisoning in Zamfara State Nigeria: Effects on Environmental Health DOI: http://dx.doi.org/10.5772/intechopen.112909*

concentrations of lead up to more than 10,000 μg/dl, which is 10 times greater than the exposure limit recommended by the Food and Agricultural Organization (FAO) of the United Nations (UN) for livestock [10].

Investigations on soil generally showed concentrations up to 8 percent higher in locations closer to drinking water wells and other surface water sources. This was suspected to have been caused by lead dust deposition and soil run-off from sites where lead-contaminated ore was being processed. Gold processing was done by repeated washing of the lead ore using metal head pans by decantation process to extract gold. The contaminated water and soil containing the lead ore were continuously spread all over surfaces within the residential compounds and surrounding areas [5]. At ore processing locations, incidental inhalation and ingestion of soil are a common source of exposure particularly for infants and toddlers, ingestion commonly occurs via hand-to-mouth behavior and eating food with contaminated hands [2]. Reports indicated that lead poisoning incidence from illegal mining activities in Zamfara State from 2010 to 2011 had led to the death of at least 735 children, mostly aged 0 to 5 years, and has left thousands of others ill with the lead poisoning [11].
