While granite and other decorative stone can contain some trace natural radioactivity, granite countertops are not considered to be a key contributor to radiation in the average home.
Natural stones used in bulk are noted as “possibly” posing a risk of exposure above 1 mSv, but even the largest granite, or other solid stone worktops, will not present a risk of exposure to radiation in excess of the recommended dose of between 0.3 and 1 mSv per year.
It is possible for any granite sample to contain varying concentrations of uranium and other naturally occurring radioactive elements. These elements can emit radiation and produce radon gas, a source of alpha and beta particles and gamma rays (see www.epa.gov/radiation/radiation-terms-and-units).
The Reality: Some granite countertops have been found to give off trace amounts of radon, and reporters cited a few kitchens with radon levels as high as 25 times the EPA's safety limit of 4 picocuries per liter of air.
Quartz and granite contain varying amounts of uranium, thorium, and potassium, which are naturally radioactive. Uranium and thorium decay to a radioactive gas, radon, which in turn decays to other radionuclides.
Both marble and travertine typically have much lower concentrations of naturally occurring radioactivity than does granite. If you are interested, you can review some of the ATE questions and answers related to radioactivity in home building products at this link.
It's bacteria-free, non-porous, very resilient, and non-porous. Consequently, it will need less maintenance and upkeep than granite. However, the look of quartz is uniform and although it imitates natural stones, it comes in well-established colors and designs.
With the concern over the radioactive risk potential of granite countertops, it is important to remember that we are always exposed to a certain level of background radiation. All granite, and most earthen materials, contain trace amounts of uranium and radium, emit gamma radiation and release radon gas.
Radon is more commonly found where uranium is relatively abundant in bedrock at the surface, often in granite, shale, and limestone. The EPA produced a map of the US showing geographic variation in radon concentrations, divided into three levels of risk: low, medium, and high (Figure 10.21).
Types of Intrusive Igneous Rock With Large Crystals
Granites that emit the most radon are the ones that contain the most uranium. Radon can be a carcinogen and is therefore a health concern, especially in poorly ventilated indoor spaces.
Rocky Mountains: Granites and metamorphic rocks in these ranges contain more uranium than sedimentary rocks to the east, resulting in high radon in indoor air and in ground water.
Radon is produced from the natural radioactive decay of uranium, which is found in all rocks and soils. Radon can also be found in water. Radon escapes from the ground into the air, where it decays and produces further radioactive particles.
Building materials, such as brick, marble and granite, contain very low-levels of naturally-occurring radioactivity. However, these materials can emit radon as the materials decay, which can elevate the indoor radon levels in your home. It's important to test your home for radon and to correct elevated levels.
At this time, one generally accepted radiation testing protocol for countertops does not exist, and neither imported nor domestic granite products require radiation testing. Radiation concentrations can only be measured using multiple portable instruments or with laboratory equipment.
The most uraniferous and fertile rocks are the peraluminous two- mica granitic suite, although not all two-mica plutons are enriched in uranium.
Although quartz countertops will have less to zero radon, it does not preclude granite as a “less safe” choice in kitchen countertops.
Answer: All types of houses can have radon problems-old homes, new homes, drafty homes, insulated homes, homes with basements and homes without basements. Construction materials and the way the home has been built may also affect radon levels, but this is rare.
Because radon comes from rocks and soils, radon typically collects in rooms that are in contact with the ground, like basements.
The ten states with the highest radon levels are Alaska, South Dakota, Pennsylvania, Ohio, Washington, Kentucky, Montana, Idaho, Colorado, and Iowa. Alaska is the state with the highest radon levels in the US with 10.7 pCi/L.
Radon released from granite building materials can be released over the lifetime of use but typically will be diluted by ventilation. In addition to radon, naturally occurring radioactive elements in the granite can emit small amounts of beta and gamma radiation.
It isn't a surprise that granite emits radiation. So do other items in our households. The amount of radiation emitted from granite can vary depending on the natural uranium and/or thorium concentration.
Granite is naturally resistant to bacteria, but this does not mean it is impervious to germs. Regularly sealing the stone helps the surface resist liquids that can harbor bacteria. Sealing granite closes the tiny crevices and pores where bacteria can thrive.
Quartz is Easier to Maintain than Granite
This countertop achieves a high level of durability without any sealant. As opposed to Granite, which requires re-sealing each year to maintain a less superior guard against the common hot pan, spilled wine, and dirty hands. An easy to clean countertop is the new kitchen dream.
Granite is Heat Resistant
Placing a hot pan on a well-maintained granite slab will not cause it to crack or weaken. Just remember that repeatedly placing a very hot pan on the same spot may cause granite to discolor.
One of the main reasons quartz has exploded in popularity is due to appearance. Quartz has the look of stone while also allowing homeowners to customize the design. While granite offers many options in terms of appearance, you may have to search for the right piece that matches your color scheme.