Determination of Heavy Metal Concentration in Soils and Settled Dust of Automobile Workshops at Afikpo in Ebonyi State, Nigeria

Abstract

Soil and settled dust contaminated with heavy metals pose a major threat to human health. The objective of this study was to determine the concentration of heavy metals in soil and settled dust from automobile workshops in Afikpo, Ebonyi State, Nigeria. Sixteen soil samples were collected at depths (0-5, 5-10, 10-15, and 15-20 cm) from four randomly selected automobile workshops. Control samples were collected 4 kilometers away from any automotive repair activity. Four dust samples were also collected from parked vehicles at each of the four automobile workshops. Soil and settled dust samples were analyzed for heavy metal concentration, pH, and electrical conductivity. Soil pH differed significantly (P≤0.05), ranging from 4.29 to 5.78 in the workshops and 4.39 to 5.88 in the control. Electrical conductivity differed significantly (P≤0.05) among soil samples from different locations. EC ranged from 46.33 µS/cm to 312.33 µS/cm in the workshops, and 50.33 µS/cm to 80.67 µS/cm in the control. Arsenic and Mercury were not detected in soil and dust samples from both the workshops and the control. Cd concentration differed significantly (P≤0.05), ranging from 20.7 mg/kg to 708.5 mg/kg in the workshops. The concentration of lead (Pb) was higher in all the workshops than in the control, the highest concentration of Pb was 2769.6mg/kg at location D. The concentration of Cd in the dust samples ranged from 48.8 mg/kg to 439.9 mg/kg, while Pb ranged from 1200.8 mg/kg to 2500.6 mg/kg. Heavy metals detected in soil and dust samples from the workshops indicate contamination from anthropogenic waste.