Washington, Nov 20 A single cigarette butt is enough to kill 50 percent of fish in ponds, lakes, streams and the ocean, reveals a new study.

The research team led by Elli Slaughter of San Diego State University suggests that even a small amount of unburnt tobacco gripped to the filter can contaminate a litre of water.

When discarded in water these cigarette butts become a time-released capsule of compounds like nicotine, cancer-causing benzenes, heavy metals and other dangerous compounds.

According to team member Richard Gersberg, some states and municipalities have begun moving toward legislation that would ban smoking on beaches, where butts are commonly discarded.

"I've been a biologist for thirty years. I've even smoked some cigarettes, but I never thought about the chemicals that could leach out," Discovery News quoted Gersberg as saying.

"In my view, cigarette butts are more toxic than a bunch of plastic floating around in the ocean," he added.

"We've got to become intolerant towards this kind of litter, the same way we are towards larger forms of litter," said Kathleen Register, executive director of Clean Virginia Waterways, which is associated with Longwood University in Farmville, Va.

"In beach cleanups around the world, cigarette butts are the number one thing volunteers pick up. So obviously we have an enormous education challenge to inform people about this problem," she added. (ANI)