USA — Forest fires stir up as much mercury aspower plants, scattering the toxic metal after it was originally deposited byindustrial smokestacks, according to a study released Wednesday.
Scientists at the National Center for Atmospheric Research in Boulder foundthat small concentrations of mercury that had landed in soil and been absorbedby vegetation were redistributed by wildfire smoke plumes.
This may be an important pathway for the metal to end up in waterways, theresearchers said.
“This is our first step to understand whether these emissions are big orsmall. Our first estimates are they are pretty big,” said ChristineWiedinmyer, an NCAR scientist who authored the study with colleague Hans Friedli.
The researchers studied levels of mercury in the wildfire smoke in differenttypes of vegetation and measured the amount of mercury left behind in soil aftera fire.
They determined that about 48 tons of the metal are redistributed by fireseach year in the United States.
About 108 tons of mercury, a common byproduct of coal combustion from powerplants, is released annually across the country from industrial sources.
The study found that fires contribute about 30 percent of the total U.S.emissions, Friedli said.
The study, published online in the journal Environmental Science andTechnology, found that fires over the past five years have emitted particularlylarge quantities of the metal.
The next step in the research, Friedli said, is to determine how far themercury is transported and to establish the risk of increased contamination todownwind ecosystems and communities.