A Critical Examination of Environmental Health Dimensions of Urban Food System Transitions in South West Nigerian Cities

Urban food systems in South West Nigeria are undergoing rapid transitions characterized by increasing processed food consumption, expansion of informal vending, supply chain intensification, and shifting dietary patterns, generating complex and poorly understood environmental health implications across the food production, distribution, and consumption continuum. This dissertation critically examines the environmental health dimensions of urban food system transitions in Lagos, Ibadan, and Abeokuta, South West Nigeria, through an original analytical framework integrating food systems analysis, environmental health risk assessment, and political economy perspectives. A multi-city comparative design was employed, combining qualitative policy analysis, value chain mapping from farm to consumer across six food categories, systematic environmental and microbiological sampling at forty-eight supply chain nodes, and cross-sectional surveys administered to 1,400 urban consumers. Pesticide residue analysis in vegetables and fruits, food contact material chemical migration testing, and street food microbiological profiling constituted the core environmental health exposure assessment. Results revealed systematic environmental health risks at multiple supply chain nodes, including pesticide residue exceedances in thirty-eight percent of vegetable samples, migration of plasticizers from recycled packaging materials, and fecal contamination in sixty-four percent of street food samples tested. Political economy analysis identified regulatory fragmentation, weak enforcement institutions, and economic incentive misalignments as structural drivers of persistent environmental health risks. The dissertation makes an original contribution by providing the first comprehensive environmental health analysis of food system transitions in South West Nigerian cities. Keywords: food systems, urban food, environmental health, South West Nigeria, food safety.