Cape Town – Smokers often head outside to puff away in their gardens or patios to protect their families and colleagues from passive smoking, but they might still be doing harm – to plants.
New research suggests that smoking near plants may expose them to passive smoking, and cause contamination of plant-based products.
The research, which appears in the journal Agronomy for Sustainable Development, reports that passive smoking and contaminated soils could be to blame for high levels of nicotine found in spices, herbal teas and medicinal plants.
The researchers used peppermint plants ( Mentha x piperita) in a series of mulching and fumigation experiments to test the uptake of nicotine. Lead researcher Dirk Selmar from the Technical University of Braunschweig in Germany found that peppermint plants could take up high concentrations of nicotine from contaminated soils.
The study was the first to report that high levels of nicotine in certain plants originated from tobacco, and not pesticides as had been suggested before.
Previously nicotine was used in pesticides, but in Europe its use was banned five years ago because of its toxicity.
However, in recent years a large number of food crops and plant-derived products were still found to contain high levels of nicotine despite the ban.
The latest findings raised the ire of Dr Yusuf Saloojee who heads the National Council Against Smoking in Joburg.
“In South Africa we have about 60 million cigarettes butts thrown away every day. Who knows what impact they have on the environment and ecosystem for instance? We don’t know yet, but there are worrying implications.
“Some studies have found that even the lowest levels of nicotine on pregnant women cause birth effects.
“What about the impact these cigarettes butts have on the environment?” he asked.
In his research, Selmar and his team analysed plants that were mulched and fumigated with tobacco smoke for more than nine days.
They also tested nicotine-contaminated soils as a result of discarded cigarette butts.
In their analysis they found nicotine concentrations were several times higher than the maximum residue levels set by European authorities.
But researchers also found that nicotine concentration decreased as time progressed. This was likely as nicotine was taken up by the roots of the peppermint plants and processed in their leaves.