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Radon Gas coming from Granite counter tops.
What have you heard about this subject? I was in a CE class and this topic came up. Word is that Radon is coming out fron the Granite.
I spoke to an owner of a Granite Co. and this is what he sent me.
What do you know about this?
TO: All Franchisees
FROM: Franchise Advisory Support Team (FAST)
SUBJECT: Radon Gas and Granite
DATE: March 14, 2008
Dear Franchisees,
In the past few months we have received a couple of inquiries about Radon in Granite slabs or granite countertops.
Here is the reality about RADON and what you have to know to properly answer your customers. The original story broke more than 15 years ago.
In the article, it says that certain granite have intrusions of radioactive minerals inside. That may be true to a certain extent. That fact is that there is radiation all around us, and also inside certain minerals and crystals.
Saying this, the actual concentration is basically zero. You may have higher than normal levels (still not harmful) in granite coming from China, Russia, Norway and other countries around the ex Soviet block, after the disaster in
Chernobyl 20 years ago.
Every few years, somebody brings this subject up and a new chapter is written with the backing of unknown sources, usually in magazines that tend to promote different materials other than granite. We are not aware of anybody who has found this story to be true and/or provided actual proof. In this digital age, everything is available on line for people to read and make up their own mind. We have provided one of many articles found on Google: Radon in Granite
Granite&Radon-TheTruth
This information was prepared for you to distribute to your customers and others who have questions or concerns about the radon and granite issue. It is copyrighted by the Marble Institute of America, but may be reproduced, with credit given to the Marble Institute of America. Solid Surface, The Journal of the Solid Surface Industry (Volume 1 Number 1) that was published several weeks ago, included an article entitled “Granite & Radon”. The introduction to the article stated “Scientific research poses disturbing questions about the safety of granite countertops” and copies of this article have circulated around the stone industry raising questions about radon gas emissions from granite countertops. The key advertisers in this journal were Corian and Formica. The MIA has called upon several of the country’s leading scientists in geology and geochemistry to assist in preparing a response to the allegations in this article that radon gas emissions from granite countertops may be hazardous.
On reading the article, our consultants reacted with such comments as “ludicrous”, “a fabulous collage of nonsense”, ”politically motivated”, “unethical”, and “bizarre”. Donald Langmuir, PhD, Professor Emeritus of Chemistry and Geochemistry at the Colorado School of Mines and President of Hydrochemical Systems Corp., both in Golden, Colorado, has prepared a response on behalf of the Marble Institute of America that evaluates and refutes these allegations.
His report appears in full in this Special Bulletin. Dr. Langmuir received his
BA (with honors), and his MA and PhD degrees in geochemistry from Harvard
University. He served as a geochemist with the Ground Water Branch of the
U.S. Geological Survey’s Water Resources Division and subsequently taught
and conducted research for 11 years at Pennsylvania State University, with
temporary appointments at Rutgers University, the Nevada Desert Research
Institute, and the University of Sidney, Australia. Dr. Langmuir has been a
full professor at the Colorado School of Mines since 1978.
In addition to working with Dr. Langmuir and other scientists, the MIA staff
also talked with the major U.S. granite quarriers and producers about the
issue of radon emissions from granite. These companies have certainly not
ignored the issue and several have had radon testing performed on their
granites. The research done for these companies have shown that actual
levels of radon gas emissions from granites are so low as to be
insignificant and generally represent no threat to the health and well-being
of people who live or work in buildings with granite countertops, floor or
wall tiles, furniture or any other furnishings made from granite.
Marbles, limestones and stones other than granites are of such mineral
composition that they generally do not contain measurable quantities of
radon-producing material. In terms of building materials, radon emissions
from concrete, cement and gypsum could be of greater concern.
What is Radon?
Radon is a naturally occurring gas generated by the decay of trace amounts
of uranium found in the earth’s crust throughout the world. It is an unstable gas that quickly breaks down and dissipates in the air. Radon is measured in units called picocuries per liter (pCi/L). A picocurie is one trillionth (10 -12) of a curie, which is the amount of radioactivity emitted by a gram of radium. The U.S. Environmental Protection Agency (EPA) has established 4 pCi/L as the standard for indoor air; 20 pCi/L represents the maximum amount of exposure to radium that is now allowed by U.S. regulations.
To show how old this story is, read the attached memo then check the date originally prepared.
MEMO
Date: September 1, 1995
To: Marble Institute of America
From: Donald Langmuir, PhD, Professor Emeritus of Geochemistry, Colorado School of Mines, & President, Hydrochem Systems Corp.
Subject: The article ‘Granite and Radon’ published in Solid Surface.
I am appalled and dismayed that any journal would accept a pseudo-science article such as this for publication. If this article had been submitted to a reputable scientific journal, the editors and reviewers would have
demanded that the author supply scientific evidence to support his/her many
unfounded and unsupported assertions and conclusions. Lacking such evidence they would have rejected it for publication. As a separate point, I am very suspicious of a paper that has no named author. Who is responsible for this attack on granite countertops? Is it someone who stands benefit economically?
Two of the scientific experts who the author (or authors?) cites repeatedly
in the bibliography as sources of the arguments have become aware of the
’Granite and Radon’ paper. They agree with me that the author’s conclusion
that a granite countertop could emit a high and dangerous concentration of
radon to a home is both totally fallacious and ludicrous. In fact, as you
will see below, the amount of radon released from typical granite countertop is certain to be completely negligible and well below detection by any known method of radioactive analysis. I would be delighted to have a granite countertop in my home!
As to my credentials to evaluate and refute ‘Granite and Radon’, I have been conducting funded university research and publishing in peer reviewed
journals on the geochemistry of radioactive elements for nearly 20 years at
Penn State University and the Colorado School of Mines. In recognition of
this expertise, I was nominated by the National Academy of Sciences and
appointed to serve as a member of the U.S. Nuclear Waste Technical Review Board by President Reagan in 1989, and reappointed to that position for a second four-year term by President Bush in 1992.
It is worth noting that the stone industry, whether advertising countertops,
building materials or monuments, terms many stones ‘granites’ that are not
true granites to a geologist. A true granite, which is often grey or pink,
is chiefly comprised of a potassium aluminum silicate mineral (K-feldspar or
potassium feldspar) and quartz (silica or SiO2).
Rocks called granites by the industry also include magnesium silicates (e.g. peridotites and serpentines) and a host of other chemically different rock-types, most of which contain much less uranium than does true granite.
As admitted by the author of ‘Granite and Radon’, there have been no direct
measurements of radon release from granite countertops. Model calculations suggested by Dr. Richard Wanty, using a standard, scientifically accepted approach and conservative assumptions; indicate that the radon release from a granite countertop is orders of magnitude below detection by any known analytical method. Incidentally, Dr. Wanty, who is a geochemist with the U.S. Geological Survey, co-authored or co-edited four of the expert
references cited in the author’s bibliography. He has performed research and published on the geochemistry of radioactive elements for sixteen years, and studied radon as apublic health issue since 1986. Dr. Wanty’s worksheet reproduced below may be used to calculate the concentration of radon that would be released from a granite countertop. The worksheet is shown with an example calculation, assuming a ten-foot by seven-foot granite countertop.
The EPA standard, which is not to be exceeded in indoor air, is 4 picoCuries
per liter of air (4 pCi/L). Eisenbud 1 indicates that the average
contributions of radon from various sources to indoor air are 1.5 pCi/L from
the soil (under and around the house), 0.01 pCi/L from public water supplies
(0.4 pCi/L) from private wells), 0.05 pCi/L from building materials, and 0.2
pCi/L from outdoor air. These values are for the average house which is
ventilated such that over one hour the air is changed 0.5 to 1.5 times. The
vanishingly small amount of radon in household air that might be released
from a granite countertop (0.00000074 pCi/L) as computed below, has been
calculated assuming no exchange of indoor and outdoor air, which would
further trivialize its significance. Note also that the radon content of
outside air is 270,000 times greater than that released by the countertop.
There are certain properties of rocks that can increase their radon
emanation efficiency, or in other words increase the release of radon from a
given weight of rock. These are rock properties that maximize the exposure
of internal or external rock surfaces to water or air, allowing any radon
gas to escape. The author of ‘Granite and Radon’ argues that such
properties, which include rock porosity, fissuring and mylonitization, will
increase radon releases. This is probably true, however, a granite with such
properties would be too brittle to make into a countertop, and too open to
take a polish, and so would not be marketable as a countertop - unless the
rock pores were first filled with a chemical sealant. Such sealing would
also eliminate any possible radon release problems.
In summary, to show how laughable are the concerns expressed in ‘Granite and Radon’, the typical granite countertop in our example will release 7.4 x 10 -7 pCi/L of air. This corresponds to 2.7 x 10 -8 atom decays per second
(dps). This represents 0.85 decays per year. In other words, less than one
atom of radon is produced by the countertop in one year. This is hardly
worth getting excited about. I would suggest that a good way to reduce our
exposure to the radon present in outdoor air would be to build an air-tight
house out of granite countertops!
____________________ End of Memo _____________________________
We hope that you find this information insightful and that it relieves the concerns that anyone would have regarding Radon.
Sincerely,
Franchise Advisory Support Team
