I Live in the Dallas/Ft. Worth DFW area of Texas - Can Radon Be A Danger Here?
Yes it can, even in the Dallas - Ft. Worth - North Texas Area.
Alpha Energy Laboratories (who specializes in Radon testing nationwide) sent out several thousand kits at cost to see what percentage of homes had elevated radon levels. A full 10 % came back with levels above 4 pCi/L (picocuries per liter) and there was even one which measured over 100 pCi/L. So radon is not a problem just in the North or in homes with basements. It can be a problem anywhere and it varies home to home. Finding out for yourself is relatively inexpensive way to prevent possible health issues down the road.
Dallas actually has a higher percentage of elevated radon levels compared with other surrounding counties as shown below in the data taken from http://tx-radon.info/TX_counties.html
RESULTS BELOW 2 pCi/L RADON LEVELS 2 - 3.9 pCi/L RADON LEVELS 4.0+
DALLAS COUNTY RADON LEVELS COLLIN COUNTY RADON LEVELS
TARRANT COUNTY RADON LEVELS DENTON COUNTY RADON LEVELS
Q. How Long Does A Radon Test Take?
A. Many people who need a Radon test are prospective home buyers and there is often a narrow window of time to close on the property during which inspectors can be called out. Short term radon kits require a minimum of 48 hours to develop (for the test to be compliant with EPA protocol) and the Alpha Energy Lab which is located here in the Dallas area can rush reports within 24 hours. (with an extra fee being charged per radon kit)
Otherwise, test results may require up to 3-4 business days AFTER the developed charcoal kit has been delivered to the lab.
So the minimum time typically required is 3 business days with a rush fee, (provided that ScanTech is contacted in time to make it out to the target location by Mon or Tuesday morning) and 5-7 days without, plus the lab is closed on weekends and after 4 PM. In addition, the lab cannot begin processing the radon kit until at least 4 hours has elapsed after the kit has been sealed.
ScanTech now offers a faster testing option that can indicate the levels within 24 hours after deployment onsite. This test rivals or exceeds the accuracy of the charcoal kits (+/- 5 %) and is much faster and typically cheaper. The only caveat is that the testing fee plus an equipment deposit must be collected at the time of deployment or before.
There are professional grade radon detectors that can give a fairly conclusive sampling that will be within +/- 10 % of actual (as compared to +/- 25 % for some of the charcoal kits) but these typically run over $5000 and are still not in EPA protocol unless left for 48 hours or more. Some home inspectors use these and let them run for 2 hours with 8 tests of 15 minutes each. (discarding the first test and averaging the remaining 7)
Here are some good facts on Radon risk taken from the EPA's website. Here is a link to the EPA website from which the information on this page was derived.
Q. What Is the Average Level of Radon in the Home?
A. Based on a national residential radon survey completed in 1991, the average indoor radon level is 1.3 pCi/L in the United States. The average outdoor level is about 0.4 pCi/L.
Q. Is there any level which is completely safe?
A. Only 0 (none whatsoever) which is generally not practical as even the outdoor level is measurable. The risk of radon exposure is completely linear - as levels increase, so does the risk of health effects. There really is no safety threshold per se. (except 0)
Then why 4.0 pCi/L? This was set as as standard with respect to ALARA. (as low as reasonably achievable) If the standards were lower (like 2.0) then the potential cost and difficulty of mitigating certain homes and structures could become untenable. Also, below 4.0, the risk presented by radon gas becomes secondary to other potential factors and safety issues in the home. (realistic assesment of the overall picture)
Q. Is radon really dangerous?
A. On the Internet, there are rumours that radon is not really as serious as studies would suggest and that the combined health effects with smoking are greatly overstated. According to some experts, the perceived risk factor from radon goes in and out of fashion with time, but the effects are the same regardless of public perception.
The problem with health factors such as radon gas is that the onset of symptoms or effects can take a relatively long time - 10 to 20 years or more and in the meantime there is no sign that anything is amiss. It is odorless, tasteless and has no real symptoms that can be attributed. (such as headaches or dizziness from carbon monoxide poisoning) But an estimated 20,000 people die every year from radon gas in the United States, the equivalent of a jumbo jet plane crashing every week. But these deaths are not spectacular or as directly linked as a airliner wrecking, so the perception tends to be "So what?"
What is known for certain by radiation science is that radon gas is an alpha particle emitter which does cellular, DNA and biochemical damage to the human body - typically through inhalation of the gas particles into the lungs where the alpha particles can penetrate through several layers of cells in the epithelium layer.
This tombstone graph shows 15,000 deaths annually, but more recent EPA estimates are 20,000 lung cancer deaths annually due to radon - 2nd only to smoking as a direct factor.
Q. Won't discovering Radon ruin my property values or peace of mind?
A. Testing for radon is inexpensive and not very complicated. Fixing a problem typically costs less than many other home projects and repairs - sometimes just adding a vent fan is all that is necessary.
Q. Can you test the Radon level in soil before hand?
A. Yes, and normally you need special radon kits that are designed for this purpose and they need to be placed inside of a hooded enclosure. Unfortunately, studies have shown that there is little correlation between radon readings obtained in this fashion and the actual readings in a home built on the site. This is due to multiple variables in how the structure is built, type of foundation, ventillation patterns, construction materials and home design.
There are medical geology maps which can plot the relative distributions of areas in terms of the POTENTIAL (also known as RADON POTENTIAL MAPS) that structures built there are more likely to have a radon issue, but there is too much variance from one site to another for this to be a reliable predictor.
Q. Can there be Radon present in water?
A. Yes, radon gas may enter the home through contaminated well water as it is soluable in water and it may be released into the air when bathing, showering, doing dishes or other tasks. This is primarily a concern if you get your water from underground sources such as a natural spring. Drinking the water directly however, is thought to be less risky than inhaling radon found in the air. There are tests however, specifically designed to test radon in water and ScanTech can perform this service.
Q. Are there seasonal fluctuations?
In general, yes. The wintertime will tend to show higher levels due to the home being more closed up. In summertime you may not even observe an issue due to the self mitigating circulation of air from A/C or open windows. If the property tests within guidelines during the summer, it would be wise to measure again in the winter.
Also, there are diurnal fluctuations where radon tends to increase at night due to loss of wind and the "stack effect". This occurs more when outside cooler air combined with rising warm air from interior heating start to pull more radon gas from the earth.
Q. Will granite, marble or other mildly radioactive material / stone elevate the radon levels in my home?
Please see the left sidebar (scroll down to Granite Countertop FAQ) on the home page of this website to see more information on this.
The contribution of all building materials to average indoor radon concentrations is about 18.5 % or nearly 1/5th of the overall gas levels and come not just from countertops, but other materials such as the sand, cement, concrete, brick and other structural components of a dwelling.
Radon (specifically the isotope radon-222) is a gaseous radioactive element having the symbol Rn, the atomic number 86, an atomic weight of 222, a melting point of -71ºC, a boiling point of -62ºC, and as of this writing there are 35 known isotopes of radon. (an isotope is an element wit the same number of protons, but different atomic weights due to variations in the number of neutrons)
Of these isotopes, only 3 are abundant in nature (219 Rn, 220 Rn, 222 Rn) and only two are of environmental / health risk importance. (220 Rn, 222 Rn) Levels of Rn 222 are monitored the most because of the extended half-half of 3.823 days (approx 3 days 19 hours 46 minutes) as opposed to Rn 220 which has a half life of just under 1 minute. (55.6 seconds)
The half-life of an element reflects it's relative radioactive stability by giving a probabilistic time period over which 1/2 of the element decays into another isotope / element. Therefore if you have 1 liter of radon gas, in just under 4 days 50 % of it will decay into Polonium 218.
Radon 222 is an extremely toxic, (as a radioactive alpha emission source) colorless, odorless and tasteless gas which cannot be detected by human senses or even ordinary chemical testing. (several varieties of specialized detectors or kits are used depending on the application)
It can be condensed to a transparent liquid and to an opaque, glowing solid; it is derived from the radioactive decay of radium and is used in cancer treatment, as a tracer in leak detection, and in radiography. (From the word radium, the substance from which it is derived.) Sources: Condensed Chemical Dictionary, and Handbook of Chemistry and Physics, 69th ed., CRC Press, Boca Raton, FL, 1988.