Spatial Relationships of Urban Land Use, Soils and Heavy Metal Concentrations in Lagos Mainland Area

Soils are the basic and most important resources of any people. Differences in soil’s physical and chemical properties are related to the spatial distribution of land uses. Most of these human activities generate toxic substances that are transported considerable distances away from source and become accumulated in soils, sediment, water bodies and fisheries. Urban soils are largely affected by impact of urbanization whose consumptive pattern is related to the social and economic aspect of the society. The study deployed contaminant factor (CF) and geo-accumulation index (Igeo) to examine the differences in the urban soils of Lagos Mainland Area due to human activities. The topsoils of the predominant human activities identified in the area were sampled and analyzed to find out the differences in the soils due to the concentration of heavy metals among six land use types. The coefficient of variation and standard deviation techniques were deployed to study the degree of variation and compare the mean values of soil physical and chemical properties of twelve representative topsoils collected from six locations. All metals analyzed showed significant (p<0.05) variation in the concentration of heavy metals, CF and Igeo among land uses. Spatial distribution of heavy metals indicates areas of potential risks of harmful heavy metals in the urban environment which enhances action plan for remediation and protection of the urban environment.

Keywords
Urban Land use, Soils, Heavy metals, Contamination Factor, Geo-accumulation index