The AARST (American Association of Radon Scientists and Technologists) annual conference concluded this after noon. We were able to attend on Tuesday when most of the granite countertop information was presented. This article will be a short description of the significant papers and studies presented, with an indepth article on the most important studies coming soon.
The first was a presentation on Natural Radioactivity in Building Materials – Czech Experience and European Legislation. The Czechs have had radiation standards for building materials, including granite, since 1987, with both Radon and Gamma radiation being covered. Gamma dose from materials like granite and concrete must not be over .3 to 1 mSv per year exposure. To convert that into mR, add two zeros (1 mSv=100 mR), so we are looking at 30 to 100 mR maximum extra Gamma exposure per year from the material. Our US standard for total extra radiation dose is close, 100 mR per year additional radiation above the normal dose. What is significant it that the Czech level starts at 30 mR, which is close to the US suggested limit of 25% of the 100 mR from a single source.
At the show there was a small 3″ diameter core sample from a granite countertop, with 1 mR of Gamma radiation per hour being emitted. This level was measured with a very expensive and accurate meter used by Health Physicists, considered the most accurate meter available that mimics a true dose to a human. At that 1,000 uR (same as 1 mR) level, thirty hours of close contact would put you over the limit from that hot spot alone, much less the rest of the countertop. Another interesting point was that our small PM 1703’s measured the core sample at the same rate, 1,030 uR/hr or 1.03 mR, only .03% high.
Another interesting point of this paper was the finding of .1 air change rate per hour, ACR. Other papers also identified .1 as being a common result for a new home built to energy efficient standards. The MIA paid Dr. Chyi to do a paper in the spring of this year, but they claimed that up to 6 ACH was common, or 60 times the rate that the Czech study found possible. A more recent paper that the MIA paid Dr. McCarthy to put together claimed .5 ACH (although they called it AER). The MIA continues to use both papers, despite the contradictions, and now it seems a far lower rate should be used.
Another interesting point was the perception of the risks from these contaminated homes. The risk from Radon and the risk from the Gamma radiation were roughly equal, but the public tended to worry far more about the radiation than the Radon.
The Czech levels of allowed Radium were 120 bq/Kg, or 10 pCi/Kg of Radium maxium allowed in a building material. Compare that 10 pCi per kilogram to the 1,030 per gram found in the Houston granite countertop. Thousands of times over the Czech allowable level.
The paper ends by saying that low radiation level material should be used whenever possible and that the public should be aware of their choice in the matter.
Next up of interest for the countertop fabricator or consumer was Elevated Radon Levels In High Rise Condominiums From Concrete Emanation. The author, Bill Brodhead, has also been helping on our granite testing effort.
What was relevant about this study was that concrete, as in concrete countertops, can also add to the Radon levels in a home. From 35 to 74 pCi/Sf/Hr of Radon was exhaling from these concrete samples, more than some low level granites. Moisture was found to raise Radon exhalation levels from 10 to 15%, which was predicted by our Uranium Geologist. Also, this study used the “meter under a bowl” testing method which has been lambasted as being an improper method of measuring Radon from granite countertops, yet the method is completely accepted in the Radon industry for this very purpose, measuring large objects like floors, walls, ceilings, and now granite countertops.
The paper also addressed elevated Gamma levels from the concrete, not a lot, only 10 uR/hr, but with so much mass emitting that 10 uR/hr, it increases a persons cancer risk a small amount. We feel that this should be a choice, an informed choice, for a consumer, whether or not to expose themselves and their families to this low level dose.
Air Change Rate, the percentage of indoor air that is replaced in a home per hour from leaks, doors opening and closing, and so on. Once it was thought that 1 ACH was the average, now it seems that homes built in the fifties and sixties are around .5 ACH, recently built homes are now assumed to be around .3 ACH, with an energy efficient home (most new homes are built to those standards) being at .1 ACH. Since the ACH is the largest factor in Radon buildup, this is a very important development. However, this study found even lower actual ACH rates, as low as .08, .03, .04 and .035 ACH. Taking the recent McCarthy paper, which used a .5 ACH rate, this shows that that rate can be from 5 to 16 times too low in some cases.
Next up was Emission of Radon From Decorative Stone by Dr. Kitto, Haines, and Hernando DiazArauzo. Dr. Kitto has been supporting the granite testing effort since late last year, initially sponsored by Build Clean, Cambria, and Sensa (Silestones natural stone product). The study linked to above is what was supposed to be published this fall, but newer stone samples that tested far, far, higher than the 35 stones tested in the study caused Dr. Kitto to hold off publication till he can add more stones to the study.
The Solid Surface Alliance provided most of those new super hot samples, which made this study turn from a pretty good resource to support the theory that some granites are dangerous and turned it into a slam dunk, debate over with, let em attempt to spin this study.
What Dr. Kitto revealed at the Radon conference on this subject is not on the link above. The study has been reopened, and what isn’t finished isn’t published. The initial study was submitted for peer review though, so one can use the info safely, plus the presentation in front of the packed room at the Radon conference was the toughest peer review process possible.
I can however, reveal some of the new info provided. We have to be careful, the MIA has been sending demand letters to those testing granite, demanding data and protocols even before the studies are finished, even in cases where third parties had paid for the work. Also, the MIA filed a Freedom of Information request on Dr. Kitto, attempting to steal his work for their own uses, or perhaps so that they can have months to attempt to discredit the work prior to publication. Two representitives from the MIA, including their Tech advisor were present though, so a littl released now will cause no harm.
One of the samples was found to be emitting 40,000 counts per minute, or 40,000 radiation decays per minute, 40,000 gamma rays. Compare this to the MIA/Langmuir paper that claimed only .85 of a decay per year from an average granite countertop. My calculator won’t go that high, but it has to be in the trillions of times more radiation than that claimed by the MIA. The next dodge that has been used was that Potassium 40 was releasing harmless Alpha radiation. Not in this case, because this was a scintillator that measured only Gamma. Only 10% of this radiation came from Potasium 40, which emits 11% of it’s radiation as Gamma.
Thirty square feet of this material would have 7.25 million pCi of Radium. A lot huh? But don’t forget the rest of the radio nucleides that WILL be present with the Radium. There are 15 other radio nucliedes present in the Uranium decay chain as well! Don’t forget the Thorium decay chain for the Thorium present.
This same thirty square feet of granite in a home would raise the Radon level to 24 pCi/L, six times the EPA action level! . Average Radon levels in US homes are 1.3 pCi/L with 21,000 deaths per year associated with those average Radon levels. Remember this when the MIA claims that granite countertops are below the EPA action levels, even the .27 pCi/L they said Crema Bordeaux has a huge death rate associated with it, if you used .27 pCi/L as the average home Radon level, an extra 4,375 extra lung cancer deaths per year would result.
Dr. Kitto did say that normal ventilation would reduce this 24 pCi/L to half, or 12 pCi/L.
Another very revealing thing showed up in Dr. Kitto’s work, granite is far, far, far, more porous than anyone dreamed. He took a known high emission granite, put a known low emitting granite on top, then sealed his meter and cover on top of the low level stone. Guess what? The Radon was only a little lower, the high level slab’s Radon penetrated the other stone like it was hardly there. Dr. Kitto said that he found that any Radon emitted by Radium decay inside the stone will get out. Compare that with the .1 emanation Rate that the MIA/Dr. Chyi claimed was possible.
Sealers were also discounted as a way to prevent exhalation of Radon, Kitto said Radon easily penetrates sealer, or it just forces the Radon out the back or sides of the stone. Other researches like Brodhead and Levy have also shown that when one side exhales less, the other side exhales a whole lot more, sixty times more in one case. So fiberglass and resin on the back side is not a solution either, the Radon gas will find a way out.
Quartz was found to emanate no Radon in most cases, with extremely low levels found in some quartz colors, so low as to be of infestinally small risks.
Bill Brodhead presented another paper on Measuring Radon and Thoron Emanation From Concrete and Granite With Continous Radon Monitors and E-Perms.
Most of the 26 page paper deals with measuring concrete, but page 20 starts dealing with granite countertop materials. Hmmm, I wonder where he got the samples? He brings up the difference that can occur in exhalation rates from front of the stone to the back. One sample, a Juparana Bordeaux (usually called Bordeaux) had a very heavily mesh and resin back that stopped 98% of the Radon exhalation from the backside. The Crema Bordeaux sample had 8 times more Radon coming off the back side than the front side. The Niagara Gold had 40% more Radon exhaled from the back than from the front. It was recomended that any granite countertop tests include a test on the bottom of the stone as well as the top.
Next was a table of results in several formats, Table 10 in the study, pCi/Sf/Hr is the one column that interests us, the others will be useful in Europe where they use different units for measuring. Brodhead found as muc has 490 pCi per square foot of granite per hour. Compare that to the MIA/McCarthy paper that claimed only .1 to 34 pCi/SF/Hr Radon emanation, with the average being 1.9 pCi/SF/Hr. Looks like he is 14 times too low on his maximum Radon emission (it is far more, Kitto found one stone 8 times Brodhead’s maximum).
Next up is a table of data, Table 12 in the paper. This info is very unsettling to me personally because it de coupled the Gamma radiation levels from the Radon emanation. We thought that having a low Gamma rate would prevent high Radon levels automaticaly.
Look at Table 12, page 23 of the study. Compare the Gamma and the Radon exhalation for the Niagara Gold (NG), 99.3 uR/hr gives off 490 pCi/Sf/Hr of Radon, or a ratio of 4.9 pCi per uR/hr of Gamma. Then compare that to the Four Seasons sample, 25 uR/hr of Gamma but 508 pCi/Sf/Hr of Radon, or 20.3 pCi per uR/hr! Holy crap! Four times more per unit of Gamma.
This means that you can’t use high Gamma levels to screen for “safe” granites when it comes to Radon.
Brodhead then went on to calculate the increase in Radon levels with the Juparana Bordeaux (JB), the Crema Bordeaux (CB), and the Niagara Gold (NG). Look at Table 13 on page 24, .1 to .7 for granite and .8 pCi/L for a concret countertop. Pretty low, but notice the Four Seasons was not included in the chart. Before I say what it was, let me explain something. All researches will have a point they are trying to get across with their work, Bill is no exception. Bill believes, rightly so, that concrete is the larger danger for Radon because of the sheer quanity present in a condo. So he left the Four Seasons result out of Table 13, but he did give it to us verbally, as well as on a power point slide that went with his report.
He took a real world home that he tested in his previous study on concrete emitting Radon, 822 square feet with a .035 ACH, and 40 square feet of countertop. Using the Four Seasons granite sample, and it was an entire square foot measured, not a hot spot, he found 220,000 pCi of Radon coming off per hour.
The homes average Radon level would have risen 3.1 pCi/L, so if you had the average Radon level of outide air present (.40) you would have had 3.5 pCi/L present. If you had the average 1.3 pCi/L of Radon, you would have had 4.4 pCi/L of Radon present in the home. Brodhead said that the bedroom level would have been around 2 pCi/L of Radon, and the kitchen itself would have had 4 pCi/L of Radon from the granite countertop.
Absolute proof that granite countertops CAN significantly raise the Radon levels in homes. End of debate.
An interesting point for the concrete countertop fabricators, the cement accounts for most of the Radon, the sand is second, the gravel is the third largest emanation source. Most likely because of the size of the particle from what research I have done on Radon from aggragrete.
The last session of the day, and the longest, was a panel discussion on whether or not Radon testers should test granite countertops for radiation as well. The fact that they should test granite counter tops was not up for debate, all said that the papers presented by Brodhead and Kitto proved the need for Radon testing of granite countertops.
First off was Dr. Kitto, who repeated some of his findings, and said that granite tops must be measured for radiation but he wasn’t sure who should do it.
Next was a gentleman that was a Health Physicist who brought up the Health Physicist Society’s (HPS) position on granite countertops and radiation, and he was not kind to the HPS. I need to verify his name, as there were three panel members that I didn’t put name and
face together. But he had some definite opinons on Radon and radiation in granite. First off he brought up the HPS’s computation of only .13 pCi/L of Radon increase from a granite countertop which was supposed to be conservative. This Health Physicist said other wise.
He specifically pointed out the major flaws in the HPS statement, that using radiation measurments to attempt to show the Radium content was ridiculous. The HPS decided that 8 pCi/gram of Radium was average when they had no proof of that (Houston slab lab report said 1,030 pCi/g of Radium present).
Then he attacked the HPS exhalation rate of only 10% of the total Radon being emanated (emanation is the production of Radon, exhalation is how much actually gets out of the stone). Using Dr. Kitto’s test results, plus what he has learned in his very long carreer, he found the 10% claim utterly unsupported by any scientific proof.
Then he attacked the HPS claim of .5 ACH (Air Changes per Hour) to be far lhigher than reasonable, quoting other studies including Brodhead and Kitto.
He concluded that the HPS simply did not have any facts to back up their claim that granite is 100% safe nor did they properly support their finding of .13 pCi/L of Radon from a 20 uR/hr granite countertop.
This Health Physicist had one concern with Radon testers testing for radiation, he felt that they would need a Health Physicist’s support to set protocols for measuring, then also for interpreting the results. Measuring radiation is old hat for the radiation industry, but it is usually only one radioactive substance with maybe only one radio isotope. Granite has a lot of radioactive isotopes, making calibration of the meters a nightmare. It is looking like first a Gamma spectrometer reading will have to be done (think $20,000 for a good, accurate portable meter). Then a radio chemist can calculate the total radiation being emitted. Then a Health Physicist can tell you what human tissue damage will occur.
One thing though, the Health Physicists seem to restrict themselves to immeadiate damage, ignoring low level, long term damage. Their jobs depend on doing just that, witout exposing workers to radiation, you can’t fuel, run, or clean up a reactor. You can’t give a MRI or an X ray if you worry about low dose damage to DNA.
I belive that we must find oncologists, cancer doctors, to get an idea of the true danger of low dose radiation.
Next was Dr. Steck, who was eloquent but brief. He supported the other panelists concerns on granite, Radon, and radiation and said that granite must be tested for both. He brought up his earlier work for the granite industry (Cold Springs granite company back in 1988 or so) that was found to be low for American quarried granite. He pointed out that these imported granites were far different and that the potential for elevated Radon was there and had to be addressed.
Incidently, the two samples I sent Dr. Steck were 50 and 100 times more Radon emanation than anything he had tested before. He reconstructed the data from his notes back in 1988 (his original copy was lost) and sent it to me months ago, which is what most scientists will do if you express an interest in their work.
Now Dr. Steck is another of our wonderful scientists that is voluntarily supporting this testing of granite effort. He showed me graphs of the results from Radon emanation tests he had done on two of the samples the SSA has sent so far and is willing to test more samples as we find them. We have our hottest Niagara Gold sample out on loan to Air Chek (yes, the MIA’s ally in this, but they needed to be shown the truth) and our hottest Four Seasons sample out to Stan Liebert’s lab, but we are going to route them and other samples to Dr. Steck to support his research.
Bill Brodhead was next, and repeated his ACH findings that said some granites Radon will raise some homes levels of Radon. He also pointed out the combined levels being emitted by granite, tile and the concrete in a typical home. Bill said it was possible to get 20,000 pCi of granite Radon, 20,000 pCi of tile based Radon, and 70,000 pCi of Radon from the concret in a home. Added up, that is a huge Radon risk in a home. Brodhead repeated the need to test the bottom of the granite, as well as finding the hotter spots in the granite since they will be putting out the most radiation usually.
Bill pointed out that the 4 pCi/L of Radon caused by 40 square feet of the Four Seasons granite based Radon was equivilent to 600 mR per year of radiation, six times the recomended extra exposure over the normal radiation.
The official AARST position from the panel seemed to be that there was a real need to test for radiation, but they were concerned about liablitity and the experience needed to test properly. They fielded questions from the audience that tended to support the testing of granite for radiation. Finding a Health Physicist to partner will seemed to be the best idea if a Radon guy wanted to offer the service.
That is enough for tonight, missed a lot of sleep traveling and socializing at Vegas. I’ll write more tomorrow night on the conference.
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