BLOOMINGTON, Ind. -- A study by Indiana University researchers found the chlorinated flame retardant Dechlorane Plus in the bark of trees across the northeastern United States, with by far the highest concentrations measured near the Niagara Falls, N.Y., factory where this chemical is produced.
The study, by Xinghua Qui and Ronald A. Hites of the IU School of Public and Environmental Affairs, was published online last week by the journal Environmental Science & Technology. Hites is a Distinguished Professor and director of the Environmental Science Research Center at SPEA; Qui is a postdoctoral research scientist.
Hites said the study demonstrates that tree bark can be used as nature's own passive sampling device for detecting the presence and relative concentrations of chemicals in the air. Rough, porous and high in lipids, tree bark soaks up airborne gases and particles, then keeps them protected from the elements.
"It's really a very convenient technique," Hites said. The sampling doesn't hurt the tree, and "you get an integrated measurement of what the tree has been exposed to over the last few years."
The study, "Dechlorane Plus and Other Flame Retardants in Tree Bark from the Northeastern United States," provides the first data on the prevalence of the chemical in the atmosphere outside of the Great Lakes area. It identifies the epicenter of DP concentrations as being near the factory where the chemical is produced by OxyChem (Occidental Petroleum Corp.).
Concentrations in tree bark within a few miles of the factory were several thousand times higher than those found in bark at more distant sampling sites, including Indiana, Virginia and Maryland.
Qui and Hites also used tree bark to sample for brominated flame retardants at northeastern U.S. locations. They found them, but at much lower levels than a previous study by Hites and Lingyan Zhu -- published in 2006 by ES&T -- that found the epicenter of bro
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