Impact of Land Use on Concentrations of Potentially Toxic Elements in Urban Soils of Lagos, Nigeria

BACKGROUND. Among soil contaminants, potentially toxic elements (PTE) are of major significance because they are ubiquitous, toxic and persistent. Chronic exposure of humans to these elements has been linked with developmental delay, cancer, atherosclerosis and kidney damage, stomach ailments, respiratory problems, heart disease and cancer. OBJECTIVES. The present study aims to investigate current PTE concentrations in urban soils of Lagos, an example of a rapidly urbanizing megacity in a developing country. The variation in PTE (chromium (Cr), copper (Cu), iron (Fe), magnesium (Mn), nickel (Ni), lead (Pb) and zinc (Zn)) levels across different land use types was examined. Information from this study will be useful in the ranking of contaminated sites, environmental quality management, guidance for remediation, redevelopment of contaminated sites and will provide crucial information for general urban planning decisions. METHODS. Five areas spread across four local government areas were selected, representing different socio-economic areas of Lagos (Victoria Island, Lagos mainland, Ikeja, Ifako-Ijaiye and Makoko). Sampling locations within the study areas were comprised of school playgrounds, roadsides, ornamental gardens, open spaces, train stations, industrial estates and dump sites. A total of 126 samples were collected. RESULTS. The overall mean levels of PTE concentrations in this study were comparable to those found in large European cities where main pollution sources include traffic and current or former heavy manufacturing industries. CONCLUSIONS. Regulation and legislation on environmental issues, including effective solid waste management strategies and enforcement of emission standards should be emphasized in order to reduce the impact of PTE pollution on the inhabitants of urban areas in developing countries. COMPETING INTERESTS. The authors declare no competing financial interests