Abstract

Research on the toxicity of microplastics has gained significant attention due to growing environmental and health concerns. However, studies investigating the genotoxicity of these pollutants remain limited, underscoring the need for further scientific exploration. This study evaluated the cytogenetic effects of polyethylene microplastics using the Allium cepa genotoxicity assay. Thirty-five viable A. cepa bulbs were randomly divided into seven groups (n = 5 per group) and exposed in beakers containing ultrapure water (negative control), 50 mg/L lead acetate (positive control), or polyethylene microplastic suspensions at concentrations of 10 mg/L, 15 mg/L, 25 mg/L, 50 mg/L, and 100 mg/L. Root growth was monitored for seven days, after which the root tips were processed and analyzed for chromosomal aberrations. The results showed that, compared to the negative control, both root length and mitotic index were significantly (p ≤ 0.05) reduced in the treated groups, following the concentration-dependent order: 100 mg/L > 50 mg/L > 25 mg/L > 15 mg/L > 10 mg/L. Chromosomal aberrations such as c-mitosis, vagrant chromosomes, bridge fragments, and sticky chromosomes were also observed, with their frequency increasing in the order of 10 mg/L < 15 mg/L < 25 mg/L < 50 mg/L < 100 mg/L. These findings suggest that polyethylene microplastics may have the potential to induce cytogenetic damage in A. cepa, warranting further investigation in other biological systems.

Key words: Allium cepa assay, chromosomal aberrations, microplastics, mitotic index, polyethylene.