Evaluation of the genotoxic and cytotoxic impacts of Mancozeb Fungicide on the Allium cepa L. assay

Fungicides play a critical role in modern agriculture by controlling fungal pathogens and enhancing crop yields. However, increasing evidence suggests that some fungicides may pose risks to non-target organisms, including potential genotoxic effects. This study evaluated the cytotoxic and genotoxic impacts of Mancozeb, a commonly utilized dithiocarbamate fungicide, on the root tip cells of Allium cepa L. Onion bulbs were exposed to varying concentrations of Mancozeb (0.5, 2.0, 4.0, and 6.0 g/L) for three hours and several cytological parameters were assessed including inhibition of root growth, chromosomal aberrations and the mitotic index. Results demonstrated a dose-dependent reduction in root fresh weight, length of root and dry root weights, and mitotic activity. Significant chromosomal aberrations involving anaphase bridges, lagging chromosomes, stickiness, and micronucleus formation were observed, with the highest frequency of abnormalities occurring at the lowest concentration (0.5 g/L), potentially due to higher cytotoxicity inhibiting cell division at higher doses. These findings highlight the genotoxic potential of Mancozeb fungicide and its possible clastogenic and aneugenic effects. Although Allium cepa L. is a well-established model for genotoxicity screening with relevance to mammalian systems, extrapolation to human health must be approached with caution due to interspecies differences in metabolism and DNA repair. Further investigations using animal models are recommended to confirm these preliminary observations.