Bin the butt!

As well as being unsightly, cigarette butts dropped on the ground stunt plant growth, a new study has shown...

Fully smoked (the filter only), partially smoked (filter and some residual tobacco) as well as unsmoked cigarettes (fresh from the packet) were dropped onto the soil in plant pots containing grass and clover seeds. The number of seeds that germinated successfully were counted and the length of each seed sprout was measured over a 21 day period.

All of the cigarette butts, smoked and unsmoked, cut the rate of seeds that germinated and grew. "The root biomass of clover was also reduced by about half," says the study's lead author, Anglia Ruskin University researcher Dannielle Green. This matters, she explains, because plants with a smaller root mass “are not as stable and are less able to absorb the water and nutrients that they need to grow."

“Most cigarette filters are made out of a bio-based plastic called cellulose acetate, which is derived from plants,” says Green. Nevertheless, butts can take up to 10 years to degrade and "they're made of thousands of tiny microfibres, which are a type of microplastic. The plastic itself is decreasing plant germination and growth.”

When the fully smoked cigarette butts were placed on the soil, the number of seeds that germinated was reduced compared with those that grew in control "butt-free" soil, leading the team to conclude that microplastics in the filters were in some way responsible.

The tobacco, nicotine and additional toxins in the butts from partially-smoked cigarettes were observed to “have stronger effects” on plant growth, and even fewer seeds sprouted in pots littered with them.

Perhaps more surprising was that even the seeds in the pots dosed with unsmoked cigarettes also grew less well, showing that the smoking process was not necessary for cigarettes to hinder plant growth.

Off the back of the study, smokers are being urged to think about the health of the environment, as well as their own health, whenever they light up and to "bin the butt" not drop it on the ground.