http://www.cigarettelitter.org/
It is estimated that several trillion cigarette butts are littered worldwide every year. That's billions of cigarettes flicked, one at a time, on our sidewalks, beaches, nature trails, gardens, and other public places every single day. In fact, cigarettes are the most littered item in America and the world. Not only does cigarette litter ruin even the most picturesque setting, but the toxic residue in cigarette filters is damaging to the environment, and littered butts cause numerous fires every year, some of them fatal.
Typically wind and rain carry the cigarette into the water supply, where the toxic chemicals the cigarette filter was designed to trap leak out into aquatic ecosystems, threatening the quality of the water and many aquatic lifeforms. Cigarette butts may seem small, but with several trillion butts littered every year, the toxic chemicals add up!