News Brief: Smokin’ plants

Plants turn out to be secondhand smokers. They breathe in smoke, nicotine and other pollutants released by burning tobacco. And that can be a good thing for people. By sharing our environment with green plants, people may be able to breathe easier. But can plants that people eat also suck up pollutants? Yes, a new study finds. And that may explain why nicotine has been found in some herbal teas, its authors note.

A quarter-century ago, NASA scientists showed that houseplants could filter formaldehyde, benzene and other nasty pollutants from the air. As reported in Science News, a broad range of plants could do this — everything from spider plants and Gerbera daisies to mums and English ivy. So perhaps it’s not surprising that greenery also can remove smoking related pollutants such as nicotine.

Dirk Selmar works at the Technical University of Braunschweig, Germany. His research team recently decided to work with peppermint plants. They trapped pots of them with fumes from 11 smoked cigarettes. Within two hours, peppermint leaves had picked up a “tremendously” high amount of nicotine, the researchers now report.

Nicotine is the addictive chemical in tobacco that makes it so hard for smokers to give up their habit. Smokers inhale plenty of nicotine. They also exhale some. And as tobacco burns, it also releases nicotine into the air. Even eight days after the plants encountered the cigarette smoke, their leaves’ spike in nicotine had dropped by only half.

But air is not the only route by which plants can become exposed to nicotine. Roots can also take up the pollutant from soil. For instance, the researchers sprinkled 100 milligrams of tobacco — about an eighth to a tenth of what would be in a cigarette — onto the ground in which plants were growing. Nine days later, the plants’ older peppermint leaves had roughly five times as much nicotine as did those in untreated plants.

“From a food safety point of view, there is no reason to panic,” Selmar says. He intended the research to help explain unexpected amounts of nicotine in some herbal teas and spices. Smoking farmers and processors could contribute, at least somewhat, to the bonus nicotine, he now concludes.

His team described its findings April 7 in the journal Agronomy for Sustainable Development.

Power Words

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addiction  The uncontrolled use of a habit-forming drug or uncontrolled and unhealthy habit (such as video game playing or phone texting). It results from an illness triggered by brain changes that occur after using some drugs or engaging in some extremely pleasurable activities. People with an addiction will feel a compelling need to use a drug (which can be alcohol, the nicotine in tobacco, a prescription drug or an illegal chemical such as cocaine or heroin), even when the user knows that doing so risks severe health or legal consequences.

agronomy  The science of soil health and crop production.

benzene  A ring-shaped hydrocarbon molecule made from six carbon and six hydrogen atoms. It’s liquid at room temperature and easily evaporates into the air. It’s widely used in industry and a natural constituent of petroleum, gasoline and cigarette smoke. It is highly toxic if breathed in large amounts and may cause cancer after prolonged, lower dose exposure.

development  (in economics and social sciences) The conversion of land from its natural state into another so that it can be used for housing, agriculture, or resource development.

nicotine  A colorless, oily chemical produced in tobacco and certain other plants. It creates the ‘buzz’ effect associated with smoking. It also is highly addictive, making it hard for smokers to give us their use of cigarettes. The chemical is also a poison, sometimes used as a pesticide to kill insects and even some invasive snakes or frogs.

secondhand smoke  The gas and smoke particles emitted out of the burning end of a cigarette and exhaled by smokers. This pollution can be toxic and hand into the air (where it is available to be breathed in) for hours.

sustainability  (n: sustainable) To use resources in a way that they will continue to be available in the future.

toxic  Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.