Elemental dangers? metal particulates in air - autism & lung cancer

[Guest guest]

" We found that for every 1000 pounds of mercury released by industry,

there was a 17 percent increase in autism, " Palmer tells WebMD. ...

http://www.foxnews.com/story/0,2933,151065,00.html - 29k

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Environmental mercury release, special education rates, and. autism

disorder: an ecological study of Texas. F. Palmer. a,. Ã. ,

Blanchard ...

http://www.safeminds.org/research/library/Palmer-et-al-Texas-Autism-Mercury-Link\

..pdf

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EcoWellness: Elemental dangers?

By CHRISTINE DELL'AMORE

UPI Consumer Health Correspondent

http://www.upi.com/ConsumerHealthDaily/view.php?StoryID=20060915-053012-7538r

WASHINGTON, Sept. 15 (UPI) -- People who inhale tiny metal particles

contained in air pollutants may be more likely to develop lung cancer, an

epidemiological study has shown.

In a study of lung-cancer cases in Texas, researchers found an association

between exposure to metals in airborne particulate matter and incidence of

adenocarcinoma lung cancer, a type of cancer that often afflicts

non-smoking women.

" This type of research gives us an idea of what might be causing lung

cancer in women, particularly those who don't smoke, " said senior author

Dr. Coyle, an associate professor of internal medicine at UT

Southwestern Medical Center in Dallas.

The large-scale study, the first of its kind, was published in the Journal

of Thoracic Oncology.

Coyle and colleagues identified more than 80,000 lung-cancer cases from

1995 to 2000 in 254 Texas counties and compared them with data of

industrial air pollution reported to the U.S. Environmental Protection

Agency between 1988 and 2000.

The cancer rates were more prevalent in counties with the highest levels

of pollution; conversely, cancer rates were lower in counties with less

pollution.

However, Coyle and colleagues' research is still preliminary, and the link

between airborne metals and cancer is not yet conclusive.

Particulate matter, tiny particles of dirt, dust and water, settle into

the atmosphere from fossil-fuel burning usually related to industrial

processes or automobile driving. The smallest type of particles, called

PM2.5 (which refers to 2.5 micrometers, a size 100 times thinner than a

human hair) contain heavy metals, and previous research has shown they may

contribute to lung cancer.

The EPA sets limits on how much PM can be emitted as one of its six

criteria pollutants under the Clean Air Act. Every five years the agency

updates the standards; the next revision is due in 2009.

Although PM2.5's deleterious effects are well known, Coyle wanted to look

at the tiny bits of metals inside the particles -- namely, arsenic,

cadmium, chromium, cobalt, copper, zinc, nickel and vanadium. Coyle

selected these for analysis because of their ability to mimic estrogen,

their relatively high concentration in PM and their inclusion into EPA

data.

After she conducted a statistical analysis, Coyle found strong

associations between copper, chromium and zinc and lung cancer. After

further analyses, zinc, an essential nutrient in the body, came out on top

as the greatest risk factor.

It may sound strange than an essential nutrient such as zinc -- popular in

multivitamin tablets -- could be so detrimental. But Coyle said some

nutrients, when excessive, can have toxic consequences. It could be the

Texans in the study were inhaling too much of the metal from outside air,

which in turn led to their cancer.

Coyle speculates the metals are especially carcinogenic in women because

of their estrogenic effects, or ability to bind to estrogen receptors in

the lung tissue. Many other substances, both natural and manmade, trick

the body into believing it is processing estrogen, a hormone that can be

carcinogenic. Furthermore, women often do not have the ability to

metabolize carcinogens as well as men. Some studies suggest women can

combat this deficiency by eating fruits and vegetables and exercising to

reduce the amount of metals in the body.

The research team adjusted for sex, race and ethnicity and urbanization to

ensure these factors did not complicate their results. Although smoking is

the overriding cause of lung cancer, Coyle notes smoking prevalence was

similar for all the counties regardless of their rates of pollution.

However, the research team was not able to determine how much the

lung-cancer patients were exposed to PM, a weakness inherent in

observational studies, Coyle said. She plans to measure the amount of

metals in individuals in future studies.

Lung cancer is the No. 1 cause of cancer deaths in American men and women,

claiming about 160,000 lives a year. Smoking causes 87 percent of cases,

and radon, a gas present in many homes and office buildings, is thought to

make up 12 percent. Genes also play a part: Some people may have a genetic

makeup more or less susceptible to lung cancer.

Yet scientists believe other environmental carcinogens, in addition to

cigarette smoke, may be influencing lung cancer as well.

Dr. Samet, chair of epidemiology at the s Hopkins University

School of Public Health, said metals and particulate matter is an area

with promising leads for follow-up, although the early studies, such as

Coyle and colleagues', are exploratory and not conclusive.

" It's another one of those small steps along the way in understanding the

specific carcinogens of lung cancer, " said Samet, a leading expert in

tobacco smoke and its effect on lung cancer.

Even so, Coyle believes the EPA should consider the research as additional

evidence of how PM can damage human health. The study should also

reinforce the trend of eliminating secondhand smoke -- also a carcinogen

-- from public places.

" Cleaning up our air and water is what we should be striving for, " Coyle

said. " It's not enough to ask people to exercise and eat a certain diet

(when) our environment is dirty. "

--

To see how much pollution is in your county, go to: http://www.epa.gov/tri

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