Cytogenotoxicity evaluation of two industrial effluents using Allium cepa assay

The cytogenotoxic effects of the industrial effluents from paint (0, 7.2, 18, 36 and 72%) and textile (0, 1.6, 4, 8 and 16%) manufacturing were evaluated using root tip cells of Allium cepa. In this study, root length and chromosomal aberration assays were used to determine the 96 h effective concentration (96 h EC50), root growth inhibition, mitotic index and chromosome aberration rate. Based on the 96 h EC50, textile effluent was 4.5 times more toxic than the paint effluent. Analysis of Variance (ANOVA) showed that there was significant difference (P < 0.05) in the mean root length of A. cepa exposed to different concentrations of the industrial effluents. This indicated that the root growth inhibition was concentration dependent. The mitotic index (MI) decreased with increasing concentrations of paint and textile industrial effluents. The two industrial effluents induced chromosomal aberrations in root tip cells of A. cepa with vagrant chromosome, bridges and fragments and sticky chromosomes being most frequently observed. At lower concentrations bridges and fragments were the most common aberration. The suitability of A. cepa chromosomal assay as a tool for monitoring the genotoxic effects of industrial effluents and wastewater is discussed.