Radon in granite causes cancer

The allusion that appears to be made, that natural stone installed in your home is dangerous to your health, is mentioned repeatedly on the website and on a recent Houston local television news program.

It is interesting to note that the top two contributors to this non-profit organization are artificial stone manufacturers. One of those contributing manufacturers has a marketing executive on the board of directors for this particular organization.

From what can be perceived on the surface as perhaps another “green” ad campaign, it appears to be a different bias in the ongoing battle of engineered stone manufacturers against natural stone.

Be aware that granite, like most natural components found in building materials, allows vapors to pass through that could contain traces of radon. There are very small amounts of uranium in trace minerals such as biotite in some natural stones. When mined, if a large pool of biotite is exposed, the result would initially be a radon reading. However, once a piece of granite or natural stone exposed to a large amount of uranium-rich mineral in the soil is removed from the source and exposed to the air, the transmission of radon vapor would be drastically weakened and then dissipate. . Simply put, think of natural stone as a very dense sponge that allows water, air, and yes, radon to pass through the stone. Once the stone is removed from the radon source (the earth), the stone has no radon to seep through.

We support radon testing, but alluding to natural stone as a major contributor seems ridiculous.

Here are some facts about radon:

WHERE DOES RADON COME FROM?

“Radon comes from the natural radioactive decay of radium and uranium found in the soil under the house. The amount of radon in the soil depends on the complex chemistry of the soil, which varies from house to house. Levels Radon in the soil varies from a few hundred to several thousand pCi / L. The amount of radon that escapes from the soil to enter the house depends on the climate, the porosity of the soil, the humidity of the soil and the suction within the home “.

HOW DOES RADON GET HOME?

“The houses act like big chimneys. As the air in the house warms, it rises to filter the attic openings and around the upper floor windows. This creates a little suction in the lower level of the house, which draws radon out of the ground. and inside the house. (Like natural stone filters radon emission as mentioned above.) You can test this on a cold day by opening an upstairs window an inch. You will notice that the Hot air from the house is rushing out of that opening, however, if you open a basement window an inch, you will feel cool outside air coming in. This suction is what draws radon out of the ground and into the house. You might think Caulking cracks and openings in the basement floor will stop radon from entering the home. However, scientific studies show that it only takes enough unsealed cracks or holes in the sealant to equal a 1 hole / 2 “diameter to let in all the radon. Caulking from accessible cracks and joints is unlikely to permanently seal the openings radon needs to enter the home. Radon levels are likely to remain unchanged.

Fortunately, there are other extremely effective ways to keep radon out of your home. Across the country, several million people have already been tested for radon. Some houses tested as high as 2,000-3,000 pCi / L; however, there has not been a single house that cannot mitigate to an acceptable level. The difference from natural stone is that once the stone slab is removed from the source and exposed to the atmosphere, the radon is ventilated in the same way that the ventilation of a house mitigates radon emissions in the I usually.

The radiation levels of granite products, which are technically measurable, are in fact small fractional values ​​of the established thresholds for environmental safety. The truth of the matter is that granite is a safe product. It has been used for thousands of years and the relationship between granite and radon has been studied for years and years. How safe is granite? Mathematical models have been developed that show that one could live in an all-granite house or building, even sleep on granite, for an entire year and still be within very safe exposure levels.

Calculations show that if an average countertop traps an average uranium concentration of four ppm (parts per million), the radon concentration emitted by the countertop into the domestic air would be 270,000 times lower than the radon level in the outside air. The maximum level of contact you would receive for a year if you sat on a counter all the time would be about a quarter of the annual radiation from all sources. If you were only inches from the granite (like when washing dishes), the dose would be too low to measure.

To quote Donald Langmuir, PhD, emeritus professor of geochemistry at the Colorado School of Mines and president of Hydrochem Systems Corp.

“To show how ridiculous the concerns of radon emitted by natural stone are, 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 atoms of decay per second (dps). This represents 0.85 decays per year. In other words, the countertop produces less than one radon atom in a year. This is not worth getting excited about. I would suggest a good way to reduce our Exposure to radon present in the outside air would be to build an airtight house with granite countertops. 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. the exposure of internal or external rocky 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, cracking and miloniti zation, radon releases will increase. This is probably true, however a granite with such properties would be too brittle to be made into a countertop and too open to polish, so it would not be marketed as a countertop, unless the pores of the rock are first filled with a chemical. . sealant. Such sealing would also eliminate any potential radon release problems. “

In a more recent study by LL Chyi, Ph.D. and Professor of Geochemistry and Environmental Geology at the University of Akron, Akron, Ohio. Dr. Chyi studied 13 of the most popular granites used in the United States as determined by an industry-wide survey. Due to their popularity, these 13 granites are believed to account for up to 85% of the granite countertop market in recent years. The types of granite are as follows:

1. New Venetian Gold, Brazil; medium-grained gneiss, yellow-beige with many dark red garnets

2. Uba Tuba, Brazil; A medium to coarse grained olive green granite.

3. Santa Cecilia, Brazil; A coarse-grained yellowish-gray gneiss with pie-sized red garnets

4. Tropic Brown, Saudi Arabia; medium grain brown granite

5. Absolute Black, India; black basalt

6. Tan Brown, India; A black-brown igneous rock with large shapeless reddish-brown feldspar crystals.

7. Giallo Ornamental, Brazil; coarse-grained, brownish-yellow granulite with some reddish-brown garnets

8. Bordeaux cream, Brazil; Juparana Bordeaux Cream (Brunello). A coarse to very coarse grained granite, pink to red in color with areas of quartz, alkaline feldspar, and quite a bit of mineral.

9. Baltic Brown, Finland; brown-black granite

10. Giallo Veneziano, Brazil; medium to coarse grain, ocher yellow to golden brown, also light pink, gneiss

11. Dakota Mahogany, United States; medium to coarse grain reddish brown granite

12. China Black, China, a fine-grained plutonic rock

13. Yellow Star, China, a medium-grained yellow to pink granite

The test methodology was designed to measure the amount of radon that each type of granite would add to the interior of a 2,000 square foot home, normally ventilated with 8 foot ceilings. The results show that Crema Bordeaux (the most active in terms of radon emissions) would contribute a component concentration of less than 0.28 pCi / L, or less than 7% of the EPA recommended processable level of 4.0 pCi / L. This The amount of radon is far below a level that could cause health problems. Tropic Brown and Baltic Brown, second and third in radon release according to Dr. Chyi’s tests, accounted for only 1% of this action level. The other granites tested added almost immeasurable amounts of radon to the house. Radon atoms in pore spaces and cracks are minimal concern with granite countertops.

Dr. Chyi’s test results show that granites currently on the United States market are negligible contributors to radon levels in the home. “Based on test results and EPA standards, we can conclude that the most popular granites used as countertops do not pose a threat to homeowners’ health. If proper resealing is applied once a year or with other frequencies determined by industry, radon release can be further reduced. “

Daniel J. Steck, Ph.D. also ran an indoor radon and granite test, and this is what he had to say.

“The average radionuclide content of your building materials samples is similar to that of other average samples of granite and other common building materials derived from earth, such as brick and soil. Therefore, the amount of gamma radiation emitted for similar masses of these building materials it will be approximately the same;

There is little variation from sample to sample in the concentrations of radionuclides of the radon family; radon flux is somewhat higher for countertop squares than for smaller samples. This indicates that the effective diffusion length is only on the order of the thickness of the countertop samples, that is, several centimeters. Therefore, material larger than 5 cm (2 “) will probably not emit more than the countertop samples.

While we believe that health safety is a major concern, especially in our homes, it is reprehensible for an industry to attempt to gain financially through “scare tactics” or under the auspices of “environmentally friendly”. We urge the consumer not to be fooled by these scare tactics.

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