INFOTERRA: Op Ed: Potential Genetic Impacts of Air Pollution
http://enn.com/news/enn-stories/2003/01/01072003/s_49194.asp
Air pollution may alter genes
Tuesday, January 07, 2003
By David Suzuki
Six years ago, scientists found that herring gulls living near steel mills
around the harbour in Hamilton, Ontario, tended to have high DNA mutation
rates. These mutations were then transferred to the next generation of
gulls, increasing the offspring's chances of developing genetic diseases
like cancer and birth defects. Researchers suspected at the time that air
pollution was causing the mutations, but they couldn't eliminate other
factors, such as polluted water or contaminated fish, that also could have
been responsible.
Now other scientists have published a paper indicating that air pollution
is indeed the likely culprit behind the mutations. What's more, there's no
reason why human DNA should be immune from the same pollution. So our
genes may also be damaged and inherited by our children. It's sobering to
think that chemicals in our air affect us at a genetic level. Few studies
have been done on this topic outside examinations of animals exposed to
radioactive dust from nuclear accidents.
To examine the effect of air pollution, the researchers exposed two groups
of mice for 10 weeks - one just one kilometer (.62 miles) from two of
Hamilton's steel mills, the other 30 kilometers (18.6 miles) away in a
rural area. They fed both groups the same diet, gave them bottled water
and tended to them in the same way. Essentially, the only difference
between the two groups was the air they breathed.
The offspring of the group housed near the steel mills suffered from up to
twice as many mutations as offspring from the rural group. Those "steel
mill" mice also produced 20 percent smaller litters. The researchers
conclude: "We therefore attribute the effect on inherited mutations in the
offspring of sentinel mice directly to variation in air quality between
the steel and the rural field sites."
First gulls, now mice. There's a good chance that air pollution is causing
mutations in humans as well. Mice and humans are both mammals and share 99
percent of the same genes. What's bad for them is generally bad for us,
too. In this case, the damage seems to affect mostly male mice and their
offspring, but the researchers caution that female mice are likely not
immune.
That male mice were especially affected is cause for concern, given that
they were only exposed to the polluted air for 10 weeks. Steelworkers tend
to be male and may be exposed to high levels of pollutants for years.
Similarly, those living in the immediate vicinity of mills will be exposed
for long periods of time, thereby increasing the chances of genetic
damage.
Yet the steel industry response to the study was shocking. One industry
spokesperson actually told the Canadian Press: "We dismiss this study as
speculative and irresponsible." I guess I shouldn't be surprised. The
response is reminiscent of the tobacco industry line when confronted with
evidence of the harm caused by smoking. Rather than saying, "Wow, that's a
disturbing finding. We'll fund further studies and look at ways to reduce
our emissions in the meantime," industry simply dismisses sound science
out of hand.
Tobacco and steel share another commonality: the chemicals thought to be
responsible for the mutations in the Hamilton mouse study are also found
in cigarette smoke. They're called polycyclic aromatic hydrocarbons, or
PAHs, a group of about 100 different chemicals that are created largely
when fossil fuels are burned, but are also found in charred food and
cigarettes. PAH levels around steel mills in Hamilton are 50 times higher
than in rural areas.
"There is an urgent need to investigate the genetic consequences
associated with exposure to chemical pollution through the inhalation of
urban and industrial air," the Hamilton researchers say. Indeed, with the
vast majority of us now living in urban areas and millions of people
exposed to air pollution from steel mills, coal-fired power plants and
automobiles, we cannot afford to simply accept the industry line of doing
nothing - especially when it could be the next generation that suffers the
most.
Copyright 2003, David Suzuki Foundation All Rights Reserved
Copyright © 2003 Environmental News Network Inc.
*** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material
is distributed, without profit, for research and educational purposes
only. ***
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