Toxic chemicals in air
There is a good reason scientists can find 4,000 chemicals in cigarette smoke. They are in the
air all around us, most of which are legally released by industry. Slick suckers aren't they?
http://news.softpedia.com/news/About-4-000-Toxic-Chemicals-Are-Found-in-the-Air-We-Breathe-
59802.shtml,
About 4,000 Toxic Chemicals Are Found in the Air We Breathe
We still know very little about them
By Stefan Anitei, Science Editor
13th of July 2007, 09:10 GMT
The chlorine insecticides, like DDT, are known to move through the food chain and to make bald
eagle lay paper thin shelled eggs or poison the milk of the Inuit (Eskimo) women. The amounts
thrown on the fields may look minute but once these carcinogens enter the food chain in small
levels, starting with the microscopic algae, it binds to the fat molecules and reaches an
increasingly higher concentration (a process named biomagnification) while moving from algae to
larvae, fish and eagle or to seal and Inuit.
That's why they were banned in the 70's in U.S. Thousands of everyday chemicals have been
checked for their safety by assessing how easily they dissolve in water versus fat. The
water-loving ones do not build up in the food chain. But this approach ignores another way for
accumulation: air.
A new research has assessed how easily a chemical travels from the lungs into the air versus
how easily it dissolves in fats and water. It appeared that thousands of contaminants can build up
in air-breathing animals, if not water-breathing ones.
Many chemicals that dissolve relatively easy in water can persist in the air, accumulating
"specifically in nonaquatic food webs: mammals, birds, human beings. In mammals and humans,
we don't breathe water, we breathe air," said lead researcher Frank Gobas, an environmental
toxicologist at Simon Fraser University in British Columbia.
His team checked about 12,000 chemicals under review by the Canadian government to assess
their environmental and health effects; about 30 % of them could be stored by air-breathing
organisms. One example is the pesticide lindane, employed on crops but also to treat head lice,
which does not accumulate in fish but it does in Canadian wolves that had eaten caribou, which
in turn had been feeding on lichen.
"About one third of all the commercial chemicals that are in use right now belong in this group of
chemicals that are potentially biomagnifying. In Canada, it will be three to four thousand. And our
list of chemicals is small compared to the list of chemicals in the U.S. and E.U. The total chemical
count could reach as high as 10,000 worldwide, though most, if not all, will prove benign because
many may be broken down by cellular processes." said Gobas.
But there are no researches on the issue.
"We are not very good at predicting or measuring how quickly chemicals are being broken down
by organisms. [Metabolism] information is missing for more than 90 % of the chemicals in
commerce, which is a big problem." said Gobas.
The potentially toxic chemicals vary from crop pesticides to those employed in perfumes and
fabrics.
"Many years down the road, we hope to relate [metabolic transformation rates] to the physical,
chemical nature of substances. Based on structure, we would like to have a better way of
estimating metabolic rates and therefore bioaccumulation capacity. In the meantime, it might
make sense to test the airborne as well as the waterborne bioaccumulation potential of
chemicals," said Gobas.