Cytogenotoxicity evaluation of LOKPODJI and AGBOKOU sites of pollution using Allium cepa assay

The cytogenotoxic effects of LOKPODJI and AGBOKOU sites from Porto-Novo lagoon (0%, 25%, 50%, 75%, 100%) 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 (96h, EC 50 ), roots growth inhibition, mitotic index and chromosome aberration rate. According to the results obtained, water of AGBOKOU site was 2 times more toxic than those of LOKPODJI site and one has different significant between the average lengths of the roots of onions exposed in the various concentrations of the two sites (P < 0,05). This indicated that the root growth inhibition was concentrations dependent. The mitotic index (MI) decreases with increasing concentrations of water on AGBOKOU site on the other hand on the site of LOKPODJI, it decreases up to 50% and increases from 75% to 100%. Water of the two sites induced chromosomal aberrations in root tip cells of Allium cepa with chromosomal malformations such as vagrant chromosome, fragment, bridges and sticky chromosomes being most frequently observed. The common aberrations observed when the concentrations are weak are the fragments and bridges chromosomes. Genotoxicity test carried out on the chromosomes of onions roots tips made it possible to measure the genotoxic effects of water on two studied sites.