WATER
RADON:
The primary source
of radon in homes is from the underlying soil and bedrock. However, an additional source could be the water supply, particularly
if the house is served by a private well or a small community water system.
The NC Radiation Protection Section advises homeowners with private wells to follow the recommendations set forth by the North Carolina Radon-in-Water Advisory Committee.
Click here for a copy of these recommendations
These recommendations, found on page 5 of the final report, are
as follows:
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This recommendation is made recognizing that the radon-concentration in water is to help determine whether water is a significant contributor to existing indoor air radon levels. Inhalation of radon in air poses a greater health risk than ingestion of radon through water. The recommendation seeks to address the combined sources of radon from soil gas and radon released from water. The goal is to limit the combined radon exposure in the home to no more than the Environmental Protection Agency (EPA) recommended level of 4 pCi/L. As a general rule, 10,000 pCi/L radon in water will contribute 1 pCi/L radon to the air in the home.
Radon can be transported into a home through the plumbing of homes receiving water from a well. The concern with high levels of radon in water is that it can elevate the levels of radon in the home’s air. When testing water for radon, it is important to know that the data result, the number value, is viewed differently.
The NC Radon Program recommends that you first test your air for elevated radon levels. Should your radon test for the air indicated an elevated radon level, testing for radon in your well-water maybe helpful to determine if the home’s plumbing is the pathway in which the radon is entering your home.
The risk of radon in drinking water has been estimated by the EPA to cause 168 cancer deaths per year in the United States. The majority of these deaths (about 89%) are caused by breathing in radon that has gassed out of the water while washing dishes or showering, which leads to lung cancer. Overall, lung cancer deaths from airborne radon are estimated to be about 20,000 per year in the U.S. For this reason, it is always recommended that homeowners test for airborne radon in their home, as this presents the greater risk.
Testing for radon in air or water is easy and affordable. There are a number of radon test kits available online or in your local home improvement store for $20 or less.
Exposure to radionuclides has the potential to harm your health. Contact with any hazardous substances can cause health effects. The occurrence and nature of the effects depend on how much, how long and how one comes into contact with the substance.
What are radionuclides?
Radionuclides are elements that give off radiation as they break down. In nature, radionuclides can be found in rocks and soil and can get into ground water and into wells.
Gross alpha: Are alpha particles that can travel short distances and cannot travel through your skin.
Gross beta: Are beta particles that can penetrate through your skin, but are unable to travel through your body.
Both alpha and beta particles can be released as a product of radioactive decay.
Uranium: Natural uranium is a mixture of three isotopes: 234U, 235U, and 238U. The most common isotope is 238U which make up over 99% of natural uranium. 238U is the least radioactive of the three isotopes.
Radium226/228: Radium is formed when uranium and thorium break down in the environment. Uranium and thorium are found in small amounts in most rocks and soil.
Approximately 80% of exposure to radioactivity is natural and the rest comes from man-made sources. For example, exposure can occur from naturally occurring radiation from the emission of radon gas from rocks and soil, and radioactive elements in groundwater.
How could I be exposed to radionuclides
Individuals can be exposed to radionuclides by ingestion (eating or drinking) and inhalation (breathing). Dermal (skin) exposures to radionuclides are not considered to significantly contribute to increased health risks.
Certain rock types which have naturally occurring trace amounts of mildly radioactive* elements that serve as the "parent" to other radioactive contaminants ("daughter products"). These radioactive contaminants, depending on their chemical properties, may accumulate in drinking water sources at levels of concern.
*Mildly radioactive elements are defined as elements with very long half-lives.
How do radionuclides get into well water?
Radionuclides can get into ground water and into wells if you live in an area where they are naturally present in the rocks and soil.
What areas of the state are more likely to have high levels of radionuclides in groundwater?
There are limited data on the occurrence of radionuclides in North Carolina. We do know that these elements are associated with certain types of rock formations deep underground. The following map shows areas that are more likely to have elevated radon in groundwater based on the location of these rock formations. Radon co-exists with uranium, radium and other radionuclides, so this map also indicates where other radionuclides might be elevated in groundwater. Areas in or around the colored portions of this map may be impacted by radionuclides.
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