Impact of Automobile Repair Activities on Physicochemical and Microbial Properties of Soils in Selected Automobile Repair Sites in Abuja, Central Nigeria

Abstract

This research is aimed at evaluating the impact of activities carried out in automobile repair sites on quality of soils in the area. To achieve this target, soil samples were collected from five sampling points in each of the three selected sites (Apo, Kugbo and Zuba) to a depth range of 0 -15 cm using a stainless hand dug auger. Results of analyses of physicochemical properties pH, % porosity, electrical conductivity, particle size distribution, sulphate, chloride, nitrate and microbial contents of the soil samples indicate that most of the values exceeded those of control values. Levels of heavy metals in soils were determined using Automated Atomic Absorption Spectrophotometer (AAS). The results of the analysis revealed a decreasing trend in heavy metal contents (mg/kg) in soil in the three studied automobile repair sites as follows; Apo site: Cu (7668) > Zn (5360) > Cr (1174) > Fe (467) > Pb (333) > Ni > (196) > Cd (10.6); Kugbo site: Zn (1587)  > Cu (1043) > Cr (783) > Ni (234) > Fe (217) > Pb (170)  > Cd (9.47) and Zuba site: Zn (1190) > Cr (767) > Cu (512) > Fe (279) > Pb (250) > Ni (127) > Cd (10.4). Comparative analysis reveals that values of the studied heavy metals have exceeded those of control values and background values of some international regulatory bodies. Pearson’s correlation analysis reveals that some of the heavy metals had very strong correlations with one another and with some of the physicochemical properties of the soil. This indicates that the studied heavy metals have the same origin, mutual dependence and identical behaviors.