Environmental hazards of light cigarette butts and filters: physiological, cytotoxic, and genotoxic assessment using the Allium cepa L. assay.

Cigarette butts are a common form of litter that pose significant ecological risks due to their toxic components, which can accumulate in soils, impacting human health, plant growth, and soil-dwelling organisms. This study investigated the environmental implications of "light" cigarette butts, which, like regular ones, contain harmful chemicals that render them hazardous waste. The cellulose acetate filters are notably resistant to biodegradation, allowing them to persist in the environment and leach toxins. We examined the physiological, cytotoxic, and genotoxic effects of leachates from smoked light cigarette butts and unsmoked filters on Allium cepa L. at various concentrations (6.25%, 12.5%, 25%, 50%, and 100%). Results showed significant inhibition of root length and root numbers, with a notable decrease in mitotic index (MI) (p < 0.05) in root tip cells exposed to leachates, indicating cytotoxic effects. Additionally, leachates induced chromosomal abnormalities in meristematic cells, including stickiness, anaphase bridges, and micronuclei, leading to DNA damage. These findings underscore the physiological, cytotoxic, and genotoxic potential of light cigarette waste, highlighting the need for further research on its ecological risks and effective management strategies to mitigate adverse environmental impacts.