**4. Results of the lead poisoning investigations in Zamfara state**

The processing of lead-rich ore to obtain gold has resulted in extensive dispersal of lead dust in the affected villages causing widespread ingestion and inhalation of fine lead particles among the residents. Medecin Sans Frontieres (MSF) in March 2010 reported a high number of deaths among children mostly in the age range of 0–5 years from these localities. Field investigations conducted by multiple agencies in collaboration with Nigerian and Zamfara State Governments found excessive levels of lead in surface water (≤ 200 μg/l0, soil (≤ 600 ppm) and mercury levels in air (≤ 24 micrograms per cubic metre).

The first environmental health investigation report published by CDC prior to the lead poisoning investigation mission in 2010 confirmed that the primary source of lead exposure is soil ingestion but there was insufficient information on the quantities of lead in drinking water (groundwater and surface water). Likewise, the levels of lead in soil and mercury in air were not determined at the time. Report by JEU [2] revealed the lead concentrations in soil, surface and groundwater as well as mercury levels in air. Clinical investigation report [7] found that blood lead levels of affected children were unprecedented (mean = 119 μm/dl). Further investigation reports revealed that the lead pollution crisis covers at least 47 villages, affecting more than 30,000 residents. Consequently, food crops for humans and pasture for grazing animals that grow on the contaminated soil are considered toxic for consumption.
