The Spatial Patterns and Material Composition of Illegal Waste Disposal on the Lagos-Ibadan Expressway, Nigeria

Abstract

This study assessed the spatial distribution, waste composition, and microplastic contamination of illegal dumpsites along the Lagos–Ibadan Expressway in three peri-urban communities (Lotto, Loburo, and Ibafo). A cross-sectional design combined questionnaire surveys (n = 70), geospatial mapping, transect and quadrat assessments, and Fourier Transform Infrared (FTIR) spectroscopy of soil samples. Respondents reported offensive odour (90%), growth in dumpsite size (77%), and health concerns (31%), with low compliance with waste regulations (only 18 acknowledged the laws, and 14 reported compliance). Waste bill payment was rare (45 respondents did not pay). Transect surveys documented 161 waste instances and 136 illegal recycling points in “going-to” data, and 103 waste instances and 91 illegal recycling points in “return” data. The highest concentrations occurred between Interchange - Mowe (47 cases) and Ibafo - Wawa (49 cases), while the spatial map showed that illegal waste was clustered within the Mowe and Redeem areas. Waste composition was dominated by packaging materials, nylon, and takeaway materials, with Ibafo recording the highest dumping intensity (358 items), followed by Loburo (325) and Lotto (267). FTIR analysis of soil samples revealed diagnostic peaks for polyethylene, polypropylene, polyethylene terephthalate, polystyrene, and polyvinyl chloride. Two-way ANOVA results showed a marginal effect of axis on occurrence (F=3.07, p=.069), while neither the two characterised dumpsite types nor their interaction with the corridor axis was significant. The findings indicated that illegal dumping is prevalent along accessible sections of the Lagos-Ibadan corridor, which may be associated with weak enforcement and poor waste governance, with implications for environmental quality and public health.