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08-09-2008, 02:20 AM #1
Professional Scientific Organization Questions Granite Countertop Radon Methods
This is a press release (from the Marble Institute of America) rather than a copyrighted news article so I hope it is OK for me to quote it in its entirety. If not feel free to delete the offending portions.
Professional Scientific Organization Criticizes New York Times Article
Posted : Fri, 08 Aug 2008 16:01:26 GMT
Author : Marble Institute of America
Category : Press Release
CLEVELAND, Aug. 8 OH-Marble-Institute
CLEVELAND, Aug. 8 /PRNewswire/ -- The Health Physics Society (HPS) this week questioned the science and methodology behind a recent New York Times article on radon levels in granite countertops.
HPS, a scientific and professional organization whose members specialize in radiation safety, called the radon levels cited in the article "very odd." The July 24 New York Times article, "What's Lurking in Your Countertop?," reported that a radon measurement contractor stated that exposure from granite countertops in the kitchen of a summer home in upstate New York were ten times higher than in other areas of the residence and attributed the elevated levels to uranium in the granite countertops. The article also reported that radon levels in the kitchen of the home were reported to be 100pCi/L, compared to basement levels of 6pCi/L.
In a special bulletin posted on its Web site, HPS strongly took issue with those numbers, as follows: Assuming a relatively tight house with an air change rate of 0.5/hr and using average measured dose rates from granite countertop slabs, the estimated radon concentration in kitchen air would be 0.13pCi/L," HPS said. "This concentration is less than one-eighth the average radon gas concentration in U.S. homes and is well below the Environmental Protection Agency (EPA) guideline of 4pCi/L.
"There are some alerting factors when we see measurements and statements like this," the bulletin continued. "First, investigation determined that the measurement procedure was not valid. The procedure used by the contractor was not appropriate (as per EPA radon measurement methods) and did not provide a real idea of the amount of radon in the ambient kitchen air."
"Second, even if the measurement had been valid, one measurement result based on one type of granite countertop in one particular home is not an indication of radon exposure in any other kitchen with a granite countertop. What is needed is to measure many types of granite. So some members of the Health Physics Society did."
"It isn't surprising that granite emits radiation," the bulletin said. "So do other items in our households. The amount of radiation emitted from granite can vary depending on the amount of natural uranium and/or thorium concentration."
The HPS special bulletin reaffirms what a growing number of respected experts, as well as respected scientific research, have also concluded: consumers can be confident about the safety of granite countertops in their homes. Largely because of the New York Times article and similar media reports, granite and radon have become a confusing and emotional issue for consumers, many of whom are afraid to install granite countertops in their homes or are worried about the countertops they may already have. Yet -- according to some of the most noted authorities on granite, radon and risk -- their concerns are unfounded. The bottom line, they agree, is this: When it comes to countertops, the science proves that there is no reason for consumers to make health issues a factor in whether they choose granite.
For additional information, and to read the full bulletin and letter from the President of the Health Physics Society to the New York Times about the article on radon in countertops, go to Health Physics Society.
About the Marble Institute of America
For over 60 years the Marble Institute of America (MIA) has been the world's leading information resource and advocate for the natural dimension stone industry. MIA members include marble, granite, limestone, sandstone, and other natural stone producers and quarriers, fabricators, installers, distributors, and contractors around the world.
It isn’t a surprise that some granite emits radiation. So do other items in our households. The amount of radiation emitted from granite can vary depending on the amount of natural uranium and/or thorium concentration.
What is surprising is this 100 pCi/L result and what was missing from the article is that the measurement process was not valid for the determination of ambient radon air concentration in the kitchen. Obviously, one measurement in one house does not mean everyone should start removing their granite countertops.
Granite countertop external dose rate measurements that have been reported are about one and a half times greater than background dose rate measurements (or about 20 microroentgen/h). When one goes through the calculations, determining the amount of uranium in the countertop from this measurement and the amount of radon emanating from this), we find an average kitchen ambient radon concentration of 0.13 pCi/L, less than one-thirtieth of the EPA recommended limit and one-eighth of the natural ambient radon concentration in households across the United States.
. . .
However, it would be more effective in terms of risk reduction to take steps to mitigate radon concentrations throughout the home. The cost of such mitigation would likely be less than 10% of the cost of replacing kitchen countertops and would very likely result in a much greater overall risk reduction.
I think I have figured out how Stanley Liebert was able to measure a radon concentration of 100 pCi/L in the kitchen with granite countertops. If you watch the video of the CBS Early Show clip, at around the 3:00 mark Mr. Liebert is demonstrating how to use a radon test kit. The camera cuts away but Mr. Liebert is clearly covering a charcoal canister with a plastic dome. The entire assembly sits on a slab of granite. His instructions are, "This essentially is a test kit that the homeowner can buy. Essentially you install it, leave it for 3 to 4 days with a bowl over it. Essentially you close it back up." Host, "Oh, there's like charcoal or something like that? You put the lid on. You send it to a lab like yours and you can find out." Liebert, "Precisely." Host, "Wow! That's really something."
Using that setup he is NOT measuring the radon concentration in the kitchen. He is measuring the radon concentration inside the dome. This is the epitome of junk science. In my opinion, for anyone to go on a national TV show and spread this kind of junk science is laughable.
The compeditors of the granite industry have hired none other than Paul Harvey to spread their misinformation:
Paul Harvey Misleads Consumers on Radon and Granite
Tisk, tisk, tisk.
Last edited by Bruce Breedlove; 08-09-2008 at 09:20 PM."Baseball is like church. Many attend but few understand." Leo Durocher
08-09-2008, 04:27 PM #2
Re: Professional Scientific Organization Questions Granite Countertop Radon Methods
FYI, Just anther source of information re: granite countertops and radon gas:
Granite Countertops and Radon Gas
From the Technical and Science Committee
of the American Association of Radon Scientists and Technologists (AARST)
The primary concern about indoor radon gas is the increased risk of lung cancer that exists from breathing radon and its byproducts. The magnitude of the risk depends on the radon concentration in the air you breathe and how long you are breathing it. Radon gas is a serious national concern. The risk of radon-related lung cancer increases the longer you are exposed although any exposure to radon poses some risk.
Testing for radon in the air you breathe should be a high priority and the first step for anyone concerned about radon gas. The US Surgeon General, US EPA, AARST and the American Lung Association recommend that all homes be tested for radon gas.
At this time, the EPA does not believe sufficient data exists to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels.
Radon Sources Including Granite
Soil, sand, and rock underneath the home are the primary sources of indoor radon gas. The soil under a house always contains traces of uranium that eventually decays into radium that then decays directly into radon. This soil constitutes an enormous surface area for release of radon gas into the air and into buildings. Materials inside a building such as concrete, granite, slate, marble, sand, shale and other stones can also contain traces of radium that release radon with varying intensities. While natural rocks such as granite may emit some radon gas, the subsequent levels of radon in the building that are attributable to such sources are not typically high. The contribution from building materials to the indoor radon concentration is very dependent upon the building ventilation rate.
Appropriate Radon Testing Methods
Direct measurements in a building of the gamma radiation or radon emanation from a material, such as granite, is not a reliable indicator of radon concentrations that will be in the air you breathe. Attempts to use such measurements for estimating risk are subject to large errors due to the:
a) wide variability of radon emanation rates across the surface of granite.
b) significant variability in ventilation rates from home to home and room to room.
c) volume of space that the building material is contained in.
This position statement does not address the risk, if any, of gamma radiation from indoor building materials.
Practical Diagnostic Test
Diagnostic measurements of the radon in the air you breathe can provide better risk estimates.
Perform a radon measurement according to testing protocols (specified by EPA or AARST as noted below) in the lowest level (or lived-in level) of your home.
At the same time, perform another test in the room where the granite countertop or other suspect building material exists. You may also want to test in a highly occupied room, like your bedroom. (Use different rooms if these locations are on the same floor.)
Place the test devices at least 20 inches off the floor according to testing protocols and at least 20 inches away from the countertop or suspect material. Carefully follow all manufacturers' test kit instructions.
You may also contact a State licensed or nationally certified radon measurement professional to conduct the measurements for you.
If any of the test results are at or above the EPA recommended action levels retest these areas to confirm the initial results.
Interpreting Radon Test Results
For guidance on test results and protocols for measurements of radon in the air, see documents such as EPA's Citizens Guide to Radon or other EPA publications at Publications | Radon | Indoor Air Quality | Air | US EPA. Other information and publications for measuring radon in the air for home and multi-family dwellings can also be found at AARST American Association of Radon Scientists and Technologists.
If confirmed measurements are at, or above, the EPA recommended action levels, contact a State licensed or nationally certified mitigation professional to fix the home to reduce the radon levels.
Reducing Radon Concentrations
The best approach to reduce radon in the home is to install an active soil depressurization system (ASD) and reduce the entry of radon coming from the soil. In some cases, increasing the entry of outdoor air to the home is an appropriate method to reduce radon levels by dilution and improve indoor air quality. Both of these methods require a qualified radon mitigation professional to design and install the appropriate radon reduction system. Only in extreme cases would removal of the granite be necessary to reduce the radon concentration, assuming appropriate measurements confirm it as the significant source.
Testing the air you breathe is the best method to determine your risk from radon, whether the source of the radon is from the soil or from a material inside the building.
We support peer-reviewed research to identify and quantify the contributions of various building materials to indoor radon concentrations.
This statement was provided by the Science and Technical Committee of the American Association of Radon Scientists and Technologists (AARST).
This statement was prepared by AARST professionals with no external funding or other support. The sole purpose of this statement is educational and to reduce lung cancer deaths from elevated concentrations of indoor radon.
For More Information Contact:
Peter Hendrick, Executive Director
14 Pratt RD
Alstead, NH 03602
Jim, in Calvert County, MD
08-09-2008, 04:50 PM #3
Re: Professional Scientific Organization Questions Granite Countertop Radon Methods
That was posted last friday, 8 days ago. It took a full week for the MIA to find it.
During that time, we exchanged a lot of emails with the President of the Health Physicist Society and provided scientific proof that they were mistaken on a few of the issues in their stance. Face it, it you don't have all the info, you aren't going to make a good decision.
After my wife had provided a new set of calculations (their previous calculations with the exact pCi/sfhr of Radon coming from the Shivakasi top), they agreed that it was entirely possible for the kitchen to have elevated levels. The HPS figured 60 pCI/L produced from that Shivakasi top, close enough to the 100 that Stan Liebert claimed. They agreed this can be a concern.
Then a Nuclear Physicst on our side provided the evidence to show that depending on a small hand held meter to judge radiation emission is not valid science. The Physicist is finding far more radiation being emitted, again making Stan Lieberts data reasonable. The HPS has agreed this is the case.
The final fact that won them over was finding out that Dr. Kitto with the NY State Health Dept measured that exact Shivakasi granite countertop to be emitting 4,000 pCi/sf/hr. Your average granite is about 8 pCi/sf/hr. We have graphs of 50, 500, and 650 pCi/sf/hr after a few days of ingrowth, this is not that rare.
So, before you depend on info like this, take the time to call the source and verify that it has not been retracted. Remember that only a week ago, the MIA had to retract their statements that the EPA supported their claims that all granite was safe. Two days after they posted the claims, they were backing off. I have their emails and newsletters to prove it.
And you think you have "figured it out" how Liebert got his results? How about you finally took the time to watch the video since it is plain as day how he was testing.
Now, this is really easy. Liebert takes a known size container, places it over a sample, and determines the amount of Radon being emitted per square foot of countertop. Pretty simple, use the diameter and a forumla for the square feet of countertop under the bowl, then figure the bowls volume, and you have a known volume of air.
Read the Radon test, take that value along with the square footage and the amount of time the test ran, and you have X pCi/sf/hr. Figure the square feet of countertop, and Bob's your uncle.
Now how do the labs figure Radon emission, including the MIA's hired gun, Dr. Chyi? Well they take so many square feet of granite and put it in a known volume of air, read the test after a set time and you again have a pCi of Radon emitted per square foot of material.
See, it is the same method. In the lab it is a 12" square sample, in the home we don't want to chop a 12" square out of an expensive top, so we just use the top. Do I have to explain everything to you?
This is the epitome of stupidity, anyone that would go on a national forum and make these half baked accusations ought to be laughed off this forum.
And Paul Harvey said that granite countertops are a source of Radon gas. They are, even the MIA was forced to admit that after Chyi showed that Radon does come from granite countertops.
Again, you logic completely fails.
Shall we start laughing?
Or shall we take our cue from you and wonder who hired you to spread missinformation?
Get your facts straight and know something about what you speak of before blowing and going. This is the internet, this info is forever.
08-09-2008, 04:53 PM #4
Re: Professional Scientific Organization Questions Granite Countertop Radon Methods
Sorry, there was a cross post. The AARST info wasn't up. But many of the Radon test labs on our side are AARST board members or members, again AARST doesn't have the results of the tests on the exotic granites. Had they asked before making these claims, they would have been told.
Mark these words, they will be retracting that statement or modifying it on this issue.