Environmental and Geochemical Impacts of Artisanal Small-Scale Gold Mining in Zamfara State, Nigeria: Case Studies from Anka and Maru Areas

Abstract Artisanal and small-scale gold mining (ASGM) is a major source of livelihood in Zamfara State, Nigeria, particularly in Anka and Maru Local Government Areas (LGAs). While economically important, these mining activities often employ rudimentary and unregulated techniques, resulting in environmental degradation and public health risks. This study investigates the environmental and geochemical impacts of ASGM in Anka and Maru, focusing on soil and water contamination by heavy metals, including lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn).

Soil (n = 40) and water (n = 25) samples were collected from active mining sites in 2024 and analyzed using Atomic Absorption Spectrophotometry (AAS) and X-Ray Fluorescence (XRF). The Potential Ecological Risk Index (PERI) and human health risk assessment using Hazard Quotient (HQ) and Total Hazard Index (THI) were employed to evaluate ecological and public health risks associated with detected heavy metal concentrations.

Results indicate that soil samples contained elevated levels of Pb (up to 623 mg/kg), Cd (up to 12 mg/kg), Cu (up to 60 mg/kg), and Zn (up to 78 mg/kg), exceeding permissible limits set by the World Health Organization (WHO) and Nigerian Environmental Standards. Water samples also showed contamination, with Pb levels up to 0.52 mg/L and Cd levels up to 0.08 mg/L. PERI analysis revealed high ecological risks, particularly from lead, while HQ and THI assessments indicated potential non-carcinogenic health risks to local communities, especially children.

The study concludes that ASGM in Anka and Maru has significant environmental and geochemical impacts, posing serious ecological and health threats. Recommendations include implementing stricter mining regulations, promoting safer mining practices, and conducting community awareness campaigns on heavy metal exposure risks. This study provides critical baseline data to support policy formulation, environmental monitoring, and public health interventions in Zamfara State.