By Abbas Nazil
A new long-term study has revealed that cigarette butts remain in the environment for years, slowly breaking down into microplastic-like particles rather than fully decomposing.
The findings, published in Environmental Pollution, show that cigarette filters undergo complex physical, chemical and biological transformations over a decade but do not disappear completely.
Researchers found that these filters, made primarily of cellulose acetate, a durable plastic material, persist in soils and ecosystems, posing long-term environmental risks.
The study tracked thousands of discarded cigarette butts placed in different environments, including urban areas, sandy soils and nutrient-rich grasslands, over a ten-year period.
Results showed that decomposition occurs in multiple stages, beginning with a relatively fast initial breakdown followed by a prolonged phase of extremely slow degradation.
During the early weeks, cigarette butts lose some mass as soluble compounds are released, but the remaining structure resists further breakdown due to its chemical composition.
Even after ten years, a significant portion of the material remains intact, with maximum degradation reaching about 84 percent under favourable conditions and only about 52 percent in urban-like environments.
The research highlights that environmental factors such as soil quality, nutrient availability and microbial activity play a major role in determining the rate of decomposition.
In nutrient-rich soils, microorganisms gradually colonise and transform the filter material, while in less active environments the process slows significantly.
Over time, the original fibres lose their structure and become part of the surrounding soil, forming microscopic aggregates composed of degraded plastic, minerals and microbial residues.
This transformation reduces the visibility of cigarette litter but does not eliminate it, instead contributing to the accumulation of secondary microplastics in the environment.
The study also examined changes in toxicity, revealing that freshly discarded cigarette butts release harmful substances such as nicotine and heavy metals that can affect living organisms.
Although toxicity decreases over time as some chemicals are lost, it does not completely disappear, with measurable biological effects still observed after a decade.
Researchers noted that toxicity levels can fluctuate during decomposition, sometimes increasing temporarily due to the formation of new compounds.
The findings underscore the scale of the problem, as trillions of cigarette butts are discarded globally each year, making them one of the most widespread forms of litter.
Experts say the persistence of these materials highlights the need for better waste management strategies and increased awareness of their environmental impact.
The study concludes that cigarette filters represent a significant and long-lasting source of plastic pollution, requiring urgent attention from policymakers and the public.
