A Longitudinal Study of Environmental Health Outcomes in Communities Proximate to Gold Processing Operations in Zamfara State, North West Nigeria

The Zamfara State lead poisoning crisis linked to gold ore processing represents one of the most severe documented cases of artisanal mining-related public health emergency in Africa, yet longitudinal epidemiological data tracking health outcome trajectories in affected communities over time are absent from the published literature. This dissertation presents findings from a prospective longitudinal cohort study of environmental health outcomes in six communities proximate to active and legacy gold processing operations in Zamfara State over a four-year follow-up period. A cohort of 480 individuals, including 220 children aged below seven years, was enrolled and followed with annual blood lead level testing, neurodevelopmental assessments, physical growth measurements, and haematological profiling. Environmental monitoring of soil lead concentrations at each community was conducted bi-annually. Multivariate mixed-effects regression models estimated associations between environmental lead exposure and health outcomes over time, adjusting for nutritional status, socioeconomic indicators, and healthcare access. Results demonstrate persistently elevated blood lead levels in children (mean 28 micrograms per decilitre at enrolment, declining to 19 micrograms per decilitre after soil remediation in three communities) with dose-dependent associations with cognitive impairment scores and growth faltering. Communities where soil remediation was completed show significantly faster blood lead decline trajectories than unmediated communities. The dissertation quantifies, for the first time longitudinally, the health benefit attributable to remediation intervention and makes an original contribution to mine-impacted community health science. Keywords: lead poisoning, longitudinal study, Zamfara State, environmental health, gold processing.