Lead concentration in the blood of the general population living near a lead–zinc mine site, Nigeria: Exposure pathways

Abstract

Lead (Pb) poisoning in children is a major public health catastrophe worldwide. This report summarises both exposure pathways and blood Pb levels in children below 7years of age and adults (above 18years) from the Adudu community living near a lead–zinc mine in Nasawara, Nigeria. The average and median blood Pb levels in children and adults were 2.1 and 1.3μg/dL, 3.1 and 1.8μg/dL, respectively. However, Pb in 14% of adults' blood exceeded 5μg/dL, which is the recommended threshold blood Pb concentration in adults as established by the Centers for Disease Control and Prevention (CDC). Furthermore 68% of adults' blood exceeded blood Pb action level of 2μg/dL. For children, 11.4% and 31% of the blood samples exceeded 5μg/dL and 2μg/dL, respectively, while no safe blood Pb level in children has been recommended. In Nasawara, a significant difference (p<0.05) was observed between the various age groups in children with 2–4years old having the highest levels and 6year old children having the lowest Pb levels. Although this study did not detect elevated levels of Pb in children's blood in regions such as Zamfara, Nigeria and Kabwe, Zambia, a high percentage of samples exceeded 2μg/dL. Soils, floor dusts, water and crops also reveal that Pb contamination in the study area could potentially be the major cause of blood Pb in the community exposed to mining. This study also observed a significant correlation between water Pb levels of adults and blood Pb levels, suggesting that water is the major exposure pathway. This analysis highlights the need to properly manage mining activities so that the health of communities living in the vicinity of a Pb–Zn mine is not compromised.