Effects of urban land use pattern on physicochemical parameters, carbon stock and heavy metal contents of soils in Lagos, Nigeria

Abstract

It is becoming increasingly difficult to find available land in cities due to growing competition among industrial and residential use. Most often farmers use previously abandoned land to grow their crops. Unfortunately, the pollution status of these areas is often unknown, posing a potential risk to crops being grown. This study examined the impact of land use patterns on physicochemical parameters and heavy metal concentrations of soils collected from reclaimed arable land, greenhouse field and forest dry land.  The samples were analyzed for physiochemical parameters and heavy metal residues using Atomic Absorption Spectrophotometer. Data were analyzed using simple descriptive statistics, Analysis of Variance and Pearson correlation coefficients. Soil physiochemical parameters and heavy metal concentrations in the soil from the different land use types differed significantly. The range of values of heavy metals in soil showed Fe = 24.71±0.20 – 94.50±10.25 mg/kg, Pb = 0.12±0.07–2.47±0.45 mg/kg, Cd=0.05±0.03–3.11±0.03 mg/kg and Mn=0.50±0.18 – 13.80±1.38 mg/kg. The accumulation of heavy metals in greenhouse fields can lead to bioaccumulation in crops, which can have serious health consequences for those who consume them. To ensure the safety of our food supply, it is best to avoid excessive use of chemical fertilizers in growing crops.