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]]]]]]]]]] Says Low Radon Levels May Be Harmless [[[[[[[[[[[[[[[
By Malcolm W. Browne, (11/16/1988)
[Kindly uploaded by Freeman 07656GAED]
Special to the New York Times
Government warnings may be exaggerated, the physicist says.
LOS ANGELES, Sept. 27--Although exposure to high levels of
the radioactive gas radon causes lung cancer, exposures to low
concentrations of the gas may present no hazard at all, an
environmental physicist asserted today at the annual meeting of
the American Chemical Society.
The physicist, Dr. Bernard L. Cohen of the University of
Pittsburgh, said the level of radon that is hazardous has not
been determined, and he declined to make a direct challenge to
the Federal Government's recent strong warnings about the broad
extent of the radon threat nationwide.
But he cited data that suggested that the Government is being
overly cautious in urging renovation of millions of houses to
reduce radon dangers.
The Environmental Protection Agency says action to reduce
radon contamination is warranted in homes with levels higher
than four picocuries per liter of air. A picocurie is one tril-
lionth of a curie, which is a standard measure of radiation.
Millions of Homes Affected
The Federal Government has warned that millions of houses
have levels of the naturally occurring gas exceeding that
level. If Dr. Cohen's theory is correct, however, the number
of houses requiring corrective measure may be much lower.
But Dr. C. Richard Cothern of the Environmental Protection
Agency said: "Unless and until we know that there is a thres-
hold hazard level, it is prudent to assume that even the
smallest amounts of radon are dangerous." [A totally stupid
statement, BG. PS: Which of course you can see for yourself. I
just couldn't let this pass. We live in a sea of carcinogens,
but our lives are getting longer and longer. Only two types of
deadly serious cancers are way up: lung cancer caused by smok-
ing and melanoma which is possibly caused by sunlight. Smoking
plus radon may increase susceptibility to lung cancer, so stop
smoking! Take beta carotene, but don't worry about the
smallest conceivable amount of radon gas that can be measured--
the dose makes the poison--worry about falling in your
bathtub.]
Dr. Cohen's tentative findings are the latest in a long
debate over the health effects of extremely low levels of
radiation. Some scientists believe that any exposure to ioniz-
ing radiation increases the risk of cancer; others, including
Dr. Cohen, have argued that there is a threshold below which no
danger exists. [Is there any one molecule or atom of any sub-
stance that is in the least bit dangerous to a human being?,BG]
Dr. Cohen's findings are based on a review of studies of
average radon levels and average lung cancer rates in counties
in the United States, and in Scandinavia and China. The
studies, he said, have found that areas with high average
levels of radon tend to have low average rates of lung cancer.
Dr. Cothern of the E.P.A. said agency officials believed that
Dr. Cohen's work "warrants more investigation."
He said: "It's certainly true that no one knows whether there
is a threshold of radon exposure, below which there is no
hazard."
Up to 20,000 Cancers a Year
Senior Federal health officials have estimated that from
5,000 to 20,000 Americans die each year from lung cancer caused
by long-term exposure to radon. Most, but not all of these
deaths, the officials have said, occur among smokers.
Cigarette smoking dramatically raises the danger from radon.
Dr. Cohen's theory would cast doubts on these estimates,
although he did not attack them directly. He and other envir-
onmental experts who spoke here today said that if the thres-
hold theory becomes generally accepted, scientists will have to
reconsider many current assumptions regarding radiation risks.
"There doesn't seem to be any doubt that radon is by far
the most dangerous radiation most of us face," Dr. Cohen said.
"But if it turns out that radon is harmless below a certain
level, then we should probably stop worrying about the very
much lower risks created by the fallout from the Chernobyl re-
actor accident, medical X-rays, reactor gas leaks and so on."
Radon, an element, is an odorless gas created by the
radioactive decay of uranium, thorium and radium. Most radon
is produced by uranium-bearing minerals in soil and seeps into
houses from the ground. Radon in soil also dissolves in water,
which can carry it into homes where it is released into the
air. The radon decays radioactively in a few days, but in some
conditions it can accumulate to high levels. When humans
breathe the gas into their lungs, the products of its decay can
cause lung cancer.
Predicting Lung Cancer Rates
Dr. Cohen noted that the risk of contracting lung cancer as a
result of exposure to varying radon levels is calculated large-
ly on the basis of studies of workers in uranium and other
mines in the United States, Czechoslovakia, Canada and Scandin-
avia.
Predictions of lung cancer rates in ordinary homes are made
by extrapolating the radon dose rates miners were exposed to
compared with their lung cancer rates. By this standard, he
said, one could expect roughly 10,000 Americans to die of radon
exposure each year.
"These estimates predict that the lung cancer rate in an area
should be substantially affected by the average radon level,"
he said, "and that there should be a strong positive
correlation between them. However, essentially every area
found to have a high average radon level seems to have a low
average lung cancer rate."
In one area in southeastern Finland, he found, homes have an
average radon level of eight picocuries per liter of air, which
is eight times as high as the world average and three times the
average for Finland as a whole. Yet the lung cancer rate in
that area is significantly lower than elsewhere in Finland, Dr.
Cohen said.
U.S. and Swedish Studies
Another study cited by Dr. Cohen dealt with Skaraborg County
in Sweden, where the average indoor radon level, 12 picocuries
per liter of air, is the highest yet reported for a large area,
but where the lung cancer rate is only 75 percent as high as
Sweden's national average.
A similar negative correlation between average radon levels
and the lung cancer rate emerged from studies in Guangdong Pro-
vince, China, and in 310 counties in the United States. In the
statistics on American counties, Dr. Cohen said, the negative
correlation is weak, but statistically significant.
These results do not contradict the belief that high exposure
to radon results in a high risk of lung cancer, Dr. Cohen said.
In any case, the studies involved averages, rather than case by
case comparisons of the radon exposure rates of individual lung
-cancer victims and healthy control groups.
Dr. Cothern suggested that the startling coincidence of high
radon levels and low cancer rates in Dr. Cohen's study might
have been skewed by 'confounding" factors--influences not
related to radon risks, like differences in smoking rates or in
the amount of time people spend in their homes.
Participants in today's meetings agreed, in any case, that
exposure to high levels of radon exposure is dangerous, and is
also far more pervasive than had been realized a few years ago.
Dr. Tom C. Hess of the physics department at the University
of Maine in Orono reported that investigators had found one
house whose water supply contained 2 million picocuries of
radon per liter, enough to contaminate the air in the house to
a level far higher than any ever reported in a uranium mine.
* * *
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