This story first appeared in OpenFile Halifax.

The driver in the car in front of me is smoking. His left forearm leaning on the door, he taps his ash out onto the road every so often. When he’s done, he tosses the butt away. A small shower of embers flies towards me, then the what’s left of the cigarette is gone – or at least it appears to be.

Turns out it may be a little more complicated than that.

“Throwing away cigarette butts is not like throwing away an apple core,” says Dalhousie biology professor Bill Freedman. “They are definitely persistent litter – and they look crappy.”

While Tim Horton’s cups may be some of the most visible litter lining roads in the province, cigarette butts make up much larger percentage of the crap that Nova Scotians toss onto the side of the road.

Of the 16,388 pieces of litter collected for a 2008 study of litter across Nova Scotia, nearly 70% were cigarette butts. Worldwide, about 5.6 trillion butts are discarded – one way or another – each year.

Cigarette butts are made up of paper, tobacco and a sheath made of a plastic called cellulose acetate. Freedman says they look bad and can take several years to break down. But he doesn’t believe their toxicity is an issue.

Thomas Novotny is not so sure.

A professor at San Diego State University’s Graduate School of Public Health, Novotny has closely studied the environmental impact of cigarettes.

He says there is no doubt cigarette butts contain a lot of nasty compounds – 5,000 or so chemicals, including at least 40 known carcinogens. “We don’t know yet whether they cause significant environmental pollution,” Novotny says. “What we do know is they have the potential to be toxic.”

In May 2011, the journal  Tobacco Control published  a special supplement called “The Environmental Burden of Cigarette Butts” and it includes a paper co-written by Novotny on their toxicity.

The researchers put smoked cigarette butts in water – one litre per butt – then tested the effects on two types of fish: the marine topsmelt and freshwater fathead minnow. In each case, about half the fish died. The paper says it is the first to “investigate and affirm the toxicity of cigarette butts to fish.”

Novotny believes his team have “identified that cigarette butts are a pollutant” – and that leads to more questions. “Do these things bio-accumulate? Do they get into the food chains and concentrate in fish? We don’t know yet. We haven’t gotten that far.”

Look down while standing on Spring Garden Road around Park Lane and you’re likely to find yourself staring into a sea of cigarette butts – many of which will eventually wash into the city’s storm drains.

That doesn’t worry John Sibbald, pollution prevention manager with the Halifax Water Commission. Asked if cigarette butts are a concern for the Water Commissin, he says “not at all.”

“I saw in one of the magazines we get that someone did some study where they put a cigarette butt in a gallon of water and a goldfish died or something,” Sibbald says.

“Sure there are levels of toxicity related to them, but nowadays we are able to analyze all sorts of things in our storm water. We’re picking up caffeine along with other compounds we ingest as humans, and they wind up in our surface water bodies.”

But Sibbald does admit that “there’s no denying they have an impact. If it’s a measurable impact, I don’t know.”

Linda Campbell, an environmental scientist at Saint Mary’s, is an expert on how stressors influence aquatic environments. She doesn’t know of any studies done on the affects of cigarette pollution in Nova Scotia, but she says the butts contain “nicotine, metals, solvents, and other chemicals that can be toxic to many organisms” and that “they do pose a risk to aquatic organisms. Toxic responses can arise from directly consuming used cigarette butts or being exposed to chemicals that leach off discarded cigarette butts in water.”

Campbell says she’d be most concerned about areas with high numbers of visitors – such as the Public Gardens. “The duck ponds in the Halifax Public Gardens are potentially a site of high risk. I’d be most worried about aquatic animals which feed on organisms in the sediment and about zooplankton. Fish and ducks will eat anything that looks similar to their usual tasty prey, and cigarette butts – especially those with some tobacco still remaining – contain sufficiently toxic concentrations which would definitely affect the animals health.”

Toxic or not, there’s no denying that there are far too many butts making their way into the Nova Scotia environment – where they can take up to 10 years to break down.

And that’s unlikely to change anytime soon.

“Ιt’s the last acceptable form of littering,” Novotny says. “A national survey here in the US revealed that most smokers know that cigarette butts are pollution, but about 2/3 of them admit they have flicked their butts onto the ground in the last month. It’s so ingrained in the smoking ritual.”