Genotoxicity Screening of Industrial Effluents using Onion bulbs ( Allium cepa L.)

The potential cytotoxicity and genotoxicity of three industrial wastewaters (brewery, rubber and bottling) in Benin metropolis using the Allium cepa test were investigated. A series of five small onion bulbs were cultivated in 0.01, 0.1, 1, and 10% of the wastewaters (v/v) and after 48 hours, one root tip from each bulb was harvested and processed for cytological studies by the aceto-orcein squash technique. At 72h, their cytotoxic effects on the root tips showed strong growth retardation in high concentrations of all the wastewaters. Compared to the control, treatment with the wastewaters resulted in root growth inhibition with EC50 values of 35, 50 and 62% for bottling, rubber and brewery effluents respectively, and decrease in mitotic index with increasing concentration for all samples and these were statistically significant (p