Smoking has been linked to lung cancer, emphysema and other diseases, not to mention the lesser evils like bad breath, yellow teeth, and smelly clothes and hair. But, the list of problems caused by cigarettes includes not just those caused by smoking, but also by tossing the butts at the beach.
The National Oceanic and Atmospheric Association says 32 percent of all debris gathered in ocean cleanups belongs to cigarette butts. Fish and other animals may consider butts as food but be unable to digest them because of the plastic, and so die.
Then there's the issue of metals in cigarette butts. Nearly 5 trillion butts are tossed out each year around the world, but the question of what these metals does to marine life is unknown.
"It was surprising for me that there were no published studies on metal contents of cigarette butt[s] in the marine environment, and to my best knowledge my study was the first one," says lead study author Sina Dobaradaran, an assistant professor of environmental sciences at Bushehr University of Medical Sciences in Iran, via email.
Dobaradaran and his team measured the levels of cadmium, iron, arsenic, nickel, copper, zinc and manganese in cigarettes found in the sand sediment along the shore at nine locations in the northern part of the Persian Gulf in 2015. A second sample was taken 10 days later to see whether marine currents affected contamination levels. While the levels of different metals varied (depending on where the tobacco was grown and the metals used on the cigarette paper), the content of each metal wasn't significantly different.
Another issue? Cigarette butts are made of a plastic called cellulose acetate, which may act as a conduit for delivering metal to marine animals – the same way other plastics do, the researchers say.
"My results showed cigarette butts may act as a vehicle for metal transfer and its degradation may affect marine organisms [but] more research is necessary to comprehensively understand the leaching behavior of metals from cigarette butts in the marine environment," Dobaradaran says.
"The release of metals from littered cigarette butts in the marine environment may increase the potential for acute harm to local species and may enter the food chain," the authors write in their study, which was published in the journal Tobacco Control.
While the reactions of plants and animals to increased metal content can also vary – some will be adversely affected, others will increase their tolerance of the metals – the researchers point out that public awareness of the toxicity of discarded cigarettes on coastal areas may lessen the problem.