Professional Appraisal of Environmental Impact Assessment Chemistry Components for Mining Projects in Zamfara State

Environmental impact assessments for mining projects are regulatory instruments that require rigorous baseline chemical characterisation of soil, water, and air to predict and mitigate pollution risks. This study professionally appraises the chemistry components of environmental impact assessment reports for artisanal and small-scale gold mining projects approved in Zamfara State, North West Nigeria, between 2018 and 2023. Fifteen approved EIA reports were obtained and subjected to systematic document analysis using a scoring framework covering baseline water and soil chemistry, contaminant transport modelling, impact prediction methodologies, monitoring programme design, and mitigation measure specificity. Expert reviewers from the chemistry and environmental management fields validated the appraisal framework. Results show that baseline chemical characterisation in most reports was limited to basic physico-chemical water parameters, with inadequate inclusion of heavy metal speciation, mineralogical analysis, and acid rock drainage potential. Contaminant transport modelling was absent in all assessed reports. Monitoring programmes prescribed were largely qualitative and lacked enforceable performance indicators. Lead, the primary chemical hazard in Zamfara gold mining, was not adequately addressed in terms of source characterisation, exposure pathway quantification, or health risk assessment in 80 percent of reports. The study recommends the development of a Nigeria-specific EIA chemistry standard for mining, mandatory peer review by qualified chemists, and post-approval compliance verification by the National Environmental Standards and Regulations Enforcement Agency. Keywords: environmental impact assessment, mining, Zamfara, chemistry appraisal, lead contamination