Tag Archives: cigarette butt

Cigarette butts are damaging plants, new study shows

Cigarette butts, one of the most common forms of pollution, significantly hamper plant growth. Both regular and menthol cigarette filters reduce plant growth and germination success, researchers write.

Plant growth around a wooden stick versus plant growth around a cigarette butt. Image credits: Danielle Green.

Cigarette butts have become nigh ubiquitous — they’re so widespread that one recent study found them to be the most abundant form of garbage in the oceans. More than 5.5 trillion cigarettes are manufactured globally every year with a plastic-based filter, made of cellulose acetate. It is estimated that around 4.5 trillion cigarette butts are littered every year, and this type of plastic takes decades to disintegrate.

But what happens after they’re littered?

Cigarette butts are not inert. They contain a myriad of chemicals from the tobacco which they can release into the environment. A previous study found that birds purposely bring cigarette butts into their nests because these chemicals can help keep ticks at bay — but the substances also have a negative effect.

In the new study, the team used a greenhouse experiment to assess the impact of discarded filters on two common and representative plants: Lolium perenne (perennial ryegrass) and Trifolium repens (white clover). They used a number of different scenarios (smoked and unsmoked cigarettes, regular or menthol), assessing their impact on the plants’ health.

After 21 days, the results were in, and the damage was visible. Shoot length and germination success were significantly reduced by exposure to any type of cigarette filter, and the damage was more substantial when the plants were exposed to filters from smoked regular cigarettes, as opposed to those which still had some leftover tobacco.

Image credits: Danielle Green.

Although this is hardly surprising, this is the first study to assess the impact of cigarette butts on plants, says lead author Dannielle Green from Anglia Ruskin University (ARU), said:

“Ryegrass and white clover, the two species we tested, are important forage crops for livestock as well as being commonly found in urban green spaces. These plants support a wealth of biodiversity, even in city parks, and white clover is ecologically important for pollinators and nitrogen fixation.”

“We found they had a detrimental effect on the germination success and shoot length of both grass and clover, and reduced the root weight of clover by over half.”

The main takeaway of this study, researchers say, is to convince people that cigarette butts are indeed litter and they have a negative impact

“Dropping cigarette butts seems to be a socially acceptable form of littering and we need to raise awareness that the filters do not disappear and instead can cause serious damage to the environment.”

“Many smokers think cigarette butts quickly biodegrade and therefore don’t really consider them as litter. In reality, the filter is made out of a type of bioplastic that can take years, if not decades, to break down.”

The study was published in the journal Ecotoxicology and Environmental Safety.

Credit: psu.edu

Urban birds use cigarette butts as chemical weapons against parasites

Out of all the reasons you should quit smoking, maybe an unusual avian behavior will convince you. According to researchers at the National Autonomous University of Mexico, house finches collect discarded cigarette butts and use them as nest building material to ward off pests like ticks. Essentially, the birds employ a form of chemical warfare against the parasites — and some people are willingly pumping it in their lungs.

Credit: psu.edu

Credit: psu.edu

This kind of behavior has been noted for some time but despite nicotine’s antiparasitic properties, it was never clear if this was done on purpose to protect the bird’s nest or merely a coincidence. To get to the bottom of things, a team led by Constantino Macías Garcia set up an experiment involving 32 house finches (Carpodacus mexicanus) which were separated into three groups exactly one day after the eggs in their nests had hatched.

First of all, the natural nest lining was removed and replaced with artificial felt so that any parasites that might have moved in during brooding could be eliminated. The researchers introduced live ticks in the first group comprised of ten nests, dead ticks in another ten nests while the final third group made of 12 nests was left free of any parasites.

When the nest contained ticks, the finches were far more likely to add cigarette butt fiber to their nest. The weight of cigarette butt material added to these tick-infested nests was also 40 percent greater on average than the weight of cigarette butt material added to the nests were dead ticks were present.

This evidence suggests that the finches really are consciously using the cigarette butts to cleanse their nests and protect them from ticks.

“It seems that the tendency to bring to the nest cigarette butts is at least partially a response to current, and perhaps also past, parasite load,” the researchers wrote.

A positive use for cigarettes? Not necessarily.

But this sort of chemical warfare is like a double-edged sword, as we have learned from many human conflicts as well. In 2012, Garcia and colleagues reported that the more butts are present in Mexican house finch nests, the greater the number of chromosomal abnormalities in the chicks. Maybe the birds are aware of this but the trade off is acceptable to them. It’s more likely however that finches are not aware of the damage they’re causing to their own chicks since the genetic damage is far more difficult to spot.

Findings appeared in the Journal of Avian Biology.