Genotoxicity assessment of three industrial effluents using the Allium cepa bioassay

The Allium cepa assay was employed, in conjunction with physico-chemical analysis, to investigate the potential cytotoxicity and genotoxicity of three industrial effluents (soap, beverage and paint) from the southeast of Nigeria. For in situ monitoring of cytotoxicity level, inhibition of mitotic division was investigated and for genotoxicity evaluation, chromosomal aberration assay was carried out. The results showed certain sample-constituents of the wastewaters (e.g. pH, turbidity) to be at concentrations beyond the maximum permissible limits required by international regulatory authorities. On the basis of the 72 h effective concentration (72 h EC50), the paint effluent was the most toxic while the beverage effluent was the least toxic. The mean root lengths of A. cepa exposed to different concentrations of the industrial effluents, when compared to the control, were shown by Analysis of Variance (ANOVA) to be significantly (p<0.05) concentration dependent. The three industrial effluents were observed to induce chromosomal aberrations, laggards and sticky chromosomes being the most frequently seen. The findings show that a combination of physico-chemical analysis and genotoxicity assay is effective in assessing industrial effluents for the environmental monitoring of pollutants. Key words: Allium cepa, industrial effluents, soap, beverage, paint, genotoxicity