Elucidating nicotine transfer into water environments via cigarette butt remaining parts

Nicotine, the main alkaloid in tobacco, enters water environments through discarded cigarette butts (CBs), possibly causing detrimental effects. However, there is no comprehensive investigation on the long-term leaching of nicotine from the different CBs parts. Therefore, in the present study, the ecological risk and the leachate levels of nicotine from different CBs parts were investigated. Freshly smoked CBs, aged CBs collected from streets, remaining tobacco and ash of freshly smoked CBs, and filter plus paper of freshly smoked CBs were evaluated for the leachate experiments. The order of nicotine leachate from different types of CBs and parts investigated were as remaining tobacco plus ash of freshly smoked CBs > freshly smoked CBs > aged CBs > filter plus paper of freshly smoked CBs with the ranges of 5.73–17.34, 0.36–8.6, 0.31–4.12, and 0.17–2.79 mg of nicotine per g of CB or remaining parts (mg g⁻¹), respectively. The ecological risk assessment revealed that nicotine leachates from all the CBs types or their remaining parts could be highly hazardous to fish, cladocerans, algae, and Daphnia magna. Based on the mean leachate levels of nicotine via freshly smoked CBs at exposure times of 1 min to 1 month and the estimated number of littered CBs every year on a worldwide scale, freshly smoked CBs may release 380–7065 tons of nicotine into water environments.