Estimation of the heavy metals released from cigarette butts to beaches and urban environments.

Cigarette butts (CB) are considered as a commonly littered waste. This hazardous waste contains a variety of pollutants. This study was developed to estimate the release of some heavy metals from CBs to the environment in different climatic conditions in different scenarios. To this end, CBs samples were obtained through artificial smoking from 10 high-consumption brands in the Iranian market, and their samples in urban areas were taken and analyzed in terms of heavy metals pollution. The results showed that the average concentrations of Lead, Cadmium, Chromium, Zinc, Copper, Nickel in the studied CBs were 1.71, 0.36, 1.59, 24.61, 12.83, and 2.66 µg/g, respectively. The long persistency of CBs in the environment leads to increased release of all heavy metals to 9.7%. In addition, the rainfall can accelerate the leaching of heavy metals to 17.7% compared to the control scenario. The total mean concentrations of the studied metals in the CBs samples collected from the urban areas in rainy and non-rainy conditions were measured to be 32.67-51.81 μg/g, respectively. According to the data obtained for the amount of each heavy metal releases in four scenarios, 147.5 kg/year and 57.3 kg/year heavy metals are released to the environment in the worst and the best-case scenarios. This study showed that CBs littering lead to the release of heavy metals into the environment; it is necessary to reduce the density of CBs in urban and public environments by training the smokers as well as increasing the efficiency of the urban cleaning system.