Analysis of metals leached from smoked cigarette litter

BACKGROUND: Littered cigarette butts represent potential point sources for environmental contamination. In areas with substantial amounts of cigarette litter, environmental hazards may arise as chemical components are leached from the filters and smoked tobacco. OBJECTIVE: The three main aims of this study were: (1) to quantify the amount of Al, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Sr, Ti and Zn leached from cigarette butts, (2) to determine the relationship between the pH of the aqueous soaking solution and metal concentration leached and (3) to determine the relationship between the period of soaking in aqueous solution and metal concentration leached. METHODS: Smoked cigarette butts and unsmoked cigarettes were added to phials containing aqueous solutions of pH 4.00, 5.00 and 6.00 (±0.05). The metal concentration of the resultant leachates was measured via inductively coupled plasma optical emission spectroscopy (ICP-OES) 1 day, 7 days and 34 days after sample addition. RESULTS: All metals were detected in leachates 1 day after sample addition (with the exception of Cd) and were released at varying rates. No clear relationship between pH within the range typical of precipitation and metal concentration leached was observed. CONCLUSIONS: Based on the gradual release of multiple metals over the full 34-day study period, cigarette litter was found to be a point source for metal contamination. The apparent rapid leaching of other metals may increase the risk of acute harm to local organisms.