Scientists have discovered a new class of chemicals emitted from burning pine trees. From a family of compounds known for their ability to alter human DNA, the findings could change the way we look at the impact of forest fires on public health.
Alkaloids are commonly found in nature; plants produce them to help bolster the structure of leaves and pine needles, and they can be key nutrients to the right organisms. Many are prized for their beneficial effects on humans, while a select few, like morphine and caffeine are downright addictive.
But in high enough doses, alkaloids can be potent toxins.
Now Alexander Liskin and a team of researchers from the Pacific Northwest National Laboratory in Washington have discovered close to 100 different alkaloids in microscopic smoke particles lofting up from laboratory-simulated forest fires.
"When roots, leaves and needles get burned, these chemicals can be released without modification into the atmosphere," Liskin said. "They can be translated as aerosol particles hundreds or thousands of miles. It is possible that there is an impact on humans, animals, and that they get into the groundwater."
The team burned five different types of pine needles and trees common throughout western North America. Between 10 percent and 30 percent of the smoke -- which can contain many gases and particles other than alkaloids -- was made up of tiny particles of nitrogen-containing organic compounds, or NOCs, a large group of chemicals to which alkaloids belong. Most of the NOCs were alkaloids, meaning that forest fires have the potential to release large quantities of the toxins into the atmosphere.
Still, Laskin stressed that his study is preliminary -- much still needs to be studied about how the particles interact with water vapor, sunlight, and other aerosols once airborne.
"This is a first study," Julia Laskin, a co-author on the study, which is scheduled to appear in the June 1 edition of the journal "We can't really jump in and start working on regulations until more is done."
However, she said the results suggest more alkaloids are produced in cooler, smoldering fires. These are typical of controlled burns that forestry officials often set to prevent much hotter, raging wildfires. If further work bears out this conclusion, it may be possible to alter controlled burns in a way that minimizes alkaloid production.
Aerosol pollution is unquestionably deadly -- in the United States alone it kills approximately 50,000 people each year. But it is also a mystery.
"We know that smaller particles seem to be more toxic, but that's about it," Cort Anastasios of the University of California, Davis said. "We don't know what components or types of particles cause the most problems."
Of the study, Anastasios added: "It's very useful in pointing out several new classes of NOCs. They are potentially important for human health, and if they occur in large enough quantities in the atmosphere, could have significant climate effects."