Abstract

Using an Allium cepa meristem assay, this study examined the heavy metal concentrations and chromosome aberrations caused by soils taken from a spare part waste site. The soils taken from the spare part disposal site at Meme Bridge, Lokoja, Kogi State, Nigeria, were analyzed for Zinc (Zn), Chromium (Cr), Copper (Cu), Manganese (Mn), Nickel (Ni), Lead (Pb), Cobalt (Co), and Arsenic (As) using the Atomic Absorption Spectrophotometer (AAS). For 48 hours, roots from onion (Allium cepa) sets were allowed to grow in beakers containing varying concentrations of soil filtrate (i.e. 25%, 50%, 75%, and 100%) and the control. The tips were harvested for chromosomal observations between 8:00 and 9:00 a.m. West African Time (WAT). Data for mitotic phases and chromosomal aberrations were pooled under X400 magnification of the light microscope and analyzed using Analysis of Variance (ANOVA), while means with significant differences between concentrations were separated using Duncan Multiple Range Test (DMRT).  The results show that the levels of zinc (Zn), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), cobalt (Co), and arsenic (As) in the soil exceeded the World Health Organization’s minimal acceptable standards. This study also discovered vacuolated cells, binucleate cells, bridging chromosomes, defective polarity, fragmented chromosomes, variant chromosomes, C- mitotic cells, spindle disruption, and unipolar movement of chromosomes, indicating that the soil is genotoxic. A 50% concentration was discovered to stimulate dividing cells. The practice of dumping spare parts along the Meme River should be avoided due to the health and environmental consequences.