Should You Have Your Granite Countertops Tested?

What can you do if you have granite countertops and are concerned about radon? The general public has received conflicting suggestions in the last few months, on how to test for radon in granite countertops. The method of testing and the interpretation of the results are from one extreme to another, and some are claiming false positive results with different testing methods. Most devices used to test for radon in granite countertops may detect other elements that set off the device’s alarm unnecessarily, and do not distinguish radon from another natural occurring element. Just because the device emits the ticking sound when waving it over granite, does not mean it is necessarily picking up radon. The sound effect is dramatic and makes for a great presentation of concern, but the device is meant to find a “hot spot” or a concentrated area giving off some type of gamma radiation that may or may not be radon. Once you locate these hot spots, a “surface plate” test for radon is conducted on the hot spot to determine if it is radon. Air tests are also performed above the countertop, away from the kitchen (10-15 feet from granite countertops) and in the lowest living area.
 
The lab uses a different measurement for surface plate tests than they do for typical room air tests, and one must be careful and realize that a high lab test result for radon in granite doesn’t mean that the entire surface is giving off a high dose of radon. There may be only one hot spot where the radon exposure is coming from, so if your countertop has a hot spot, one must consider the total radon exposure in the structure from all possible sources. How much is too much exposure? This is where the air test kits will help with that decision. If the lab results for the air test above the countertop is high and the kits 10 feet away and in the lowest level are lower, there is likelihood that the countertop may be the problem. If the opposite is true (the kitchen air test is low but lower level air test is high), then the radon is most likely coming in from the soil and not the countertop, except at the hot spot. If it is coming from the soil, that needs to be addressed, but the next question is: what about the hot spot itself? Whether you leave it alone or consider replacement depends on how high the radon reading is at the hot spot (lab reading), where the hot spots are located on the countertop in relation to how close you are to it when you prepare food and work on the countertop, how many hot spots do you have on the countertop, and how large are they (surface area)?

Before you pay thousands of dollars for testing and removing countertops, please understand that some believe that many of the alarmists are selling fear by spreading claims of high radon in granite, but are using typical radon testing procedures designed for large air spaces, such as the rooms of a home, to measure for hot spots in granite countertops. So a high reading of a hot spot is presented to be compared with the EPA maximum recommended exposure of 4 pico curies per liter for whole room testing. This comparison is not accurate because each type of testing requires a different standard of acceptability. This is why it is so important to conduct air tests at the same time as a surface plate test on granite countertops.