Northeastern US Forests Inadvertently Made Fire Resistant
by John Laumer, Philadelphia on 11.28.07
The headline is a sick attempt at humor; but, the story is truly amazing. You really can't make stuff like this up.
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.
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.
We humans have lipids in and under our skin, just like tree bark? See the point?
Via::University of Indiana, "The proof is in the tree bark". Image credit::"Xinghua Qui collects a tree bark sample near Bloomington"
"We humans have lipids in and under our skin, just like tree bark? See the point? "
Umm, no. If your skin is also rough and porous, you may have a problem. I suggest a moisturizer. Key word being moisture- a liquid. Absorbing airborn toxins or anything else THROUGH the skin- not so much a problem.
On the other hand, this is a good bit of science for its true point- using nature to monitor industrial pollution.
>Absorbing airborn toxins or anything else THROUGH the >skin- not so much a problem.
huh?!!? whaaaa?!?!!? say it aint so?!!????
t
=== author's response follows ===
The product seems, according to an MSDS I read, to be sold in dry powdered form - with other stuff added. The added material may be there to reduce the risk of occupational exposures to the active ingredient.
It seems on the face of it fairly ridiculous to expect that an expensive dry powdered product is constantly sifting away from the factory and dispersing over hundreds of thousands of square miles to coat trees.
I suppose, therefore, unless corrected by a person with more direct knowledge, that the test results reported by these investigators indicate many decades worth of product manufacture, distribution, end use, recycling, and gradual degradation - all releasing the active ingredient as partially soluble vapor or aerosol. The propensity to disperse and eventually partition in some place like a fish or a tree can be modeled with some precision based on such parameters vapor pressure, lipid and/or water solubility, half-life associated with bio- and solar-degradation, and so on. However, this and an earlier, less benign, predecessor product (without the "plus") have been around for so long I'm not sure that EPA has carefully modeled it's behavior as they would normally do for a TSCA listing, though they likely will now, I'd guess.
I digress. Vapor dispersion and contact with trees over many states might well be through rain deposition, seems a reasonable hypothesis. Bark can absorb a lot of water and, as the authors seem to theorize here, hold onto the fire retardant that came with the rain, not only because of high surface area (certainly all would agree that some bark is smooth) but because the material has a higher lipid ,than water, solubility. NOTE: I have not read the original paper so I am speculating a bit here.
My tentative reading on the product indicates a history of use in nylon. Whether nylon in carpets textiles or clothing I can't say, but nylon is fairly ubiquitous stuff in our society. So, it seems reasonable to speculate that the material may be dispersing regionally from various nylon products. Even the best nylon eventually breaks down and loses its strength when kept indoors. This speculation has nothing directly to do with the factory of origin of course. (Let us hope the sampling staff did not wear clothing with it!)
However, and this is the key point, humans are exposed to rain; and we touch worn carpets and so on. Our skins do contain lipids. Whether the fire retardant can cross the epidermis at a significant rate I leave it to others to measure. But, my original question simply points to this possibility. I have no proof of course, one way or the other.
"We humans have lipids in and under our skin, just like tree bark? [sic] See the point?"
Yes, I believe it is the same point several grade six children made in their projects on pollution at the local elementary school last month.
Cutting edge, my good man....
Hi, reading this from the Indiana University School of Public and Environmental Affairs. Thanks for reading about the research and for your comments. You can find the original paper here:
http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/asap/abs/es072039a.html