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

became ill with unknown diseases and were suffering from vomiting, abdominal pain, headaches and seizures and many of them had died. Investigations carried out by a team of experts in the affected villages in May 2010, revealed that lead poisoning outbreak was widespread in the area. Thousands of children had dangerous levels of lead in their blood and many animals died from lead poisoning [6].

Investigations revealed alarming levels of lead concentrations in the environment. Lead concentrations in soil around the residential compounds have reached over 100,000 ppm. This is extreme over the concentration limit of 400 ppm for residential areas applicable in the USA and France. Similarly, the mean blood lead level concentration of 119 μm/dl found in more than 100 children diagnosed with severe lead poisoning in Dareta and Yargalma villages is alarming considering that 10 μg/dL blood lead level is associated with impaired neurological development in young children. Reports from 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. This was 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 concentrations of lead up to more than 10,000 μg/dl, which is 10 times greater than the exposure limit recommended by 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].

The persistent lead poisoning emergency in Zamfara State could not be resolved easily. The remediation process was a challenging and time-consuming task, involving excavation of all the contaminated soils and replacing same with clean ones to bring down the lead toxicity levels [19]. Many children affected by lead poisoning had to wait for their family compounds to be cleaned before they could start the treatment and some will require chelation for many months. A further challenge remains the purchase of sufficient chelating agents: these are expensive drugs that are not available as generics [8].
