Impact of Soils Contaminated by Automobile Servicing Waste on Seed Germination and Seedling Development in Lokoja, Kogi State

Abstract

Soil contamination from automobile servicing activities is a persistent environmental problem in many Nigerian cities, yet its implications for soil quality and early crop establishment remain poorly understood. This study assessed the physicochemical properties, heavy metal levels and their effects on seed germination and seedling development in soils collected from automobile mechanic workshops in Lokoja, Kogi State. Composite soil samples were analysed using standard laboratory procedures and maize, beans and tomato seeds were tested in germination assays. Data were evaluated using one-way ANOVA, Tukey’s HSD test and Pearson correlation analysis. Contaminated soils showed significantly elevated pH, electrical conductivity, organic matter, nitrogen, phosphorus and potassium compared with controls (p < 0.05). Heavy metals, particularly Pb (85 ± 3.0 mg/kg) and Cd (3.2 ± 0.2 mg/kg) exceeded FAO/WHO limits. Germination percentage, seedling vigour, radicle length and plumule length were markedly reduced in contaminated soils, with tomato showing the highest sensitivity. Strong positive correlations were observed among all metals (r = 0.84–0.95), while growth parameters were strongly negatively correlated with metal concentrations (–0.70 to –0.88). This study further emphasizes that automobile-servicing waste severely degrades soil quality and suppresses early plant development. It recommends improved workshop waste management, routine soil monitoring and the application of phytoremediation or bioremediation techniques to restore contaminated sites.