Cellulose acetate microfiber release from cigarette filters in agitated water

Cigarette butts (CBs) are among the most littered items in the world and consist of cellulose acetate (CA) fibers, a synthetic polymer with slow degradation rates. These fibers not only adsorb toxic compounds during smoking but also fragment into CA microfibers (MFs) upon entering aquatic environments. This study quantifies MF release from CBs under three agitation levels (0, 80, and 200 rpm) in controlled 10-day laboratory experiments and extrapolates results to estimate the environmental impacts of MF release from CB littering in New York (NYS). Upon immersion, CBs show an immediate release of loose fibers, followed by continued but slower shedding over time. Agitation at 200 rpm significantly (p < 0.001) increased MF detachment, resulting in a 1.69 times higher release compared to stagnant conditions. Fiber length showed no significant relationship with time or agitation speed (p > 0.1 for both). Extrapolation of first-day laboratory results conservatively suggests that discarded CBs in NYS could release 7.15E+07 to 1.04E+09 MFs per day. Targeted behavioral interventions (e.g., proper disposal campaigns) and structural measures (e.g., improved waste collection, recycling) have the potential to reduce these MF loads. This study provides insights into CBs as a major, yet understudied, source of MF release to aquatic environments.