Radon in Wisconsin

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According to the U.S. Surgeon General, the second leading cause of lung cancer in the United States is radon.[1] It is estimated that there are 15,000 to 22,000 radon-related lung cancer deaths in the United States annually.[2] Given the serious threat to the health of the general populous, it is important to know what radon is and how to prevent being affected negatively by it. Radon in Wisconsin is an important environmental issue as certain regions in the state have higher levels of radon than what is considered to be safe background levels.[3]

"This map compares Wisconsin bedrock geology and indoor radon concentrations. The shaded areas indicate elevations in indoor radon."
"This map compares Wisconsin bedrock geology and indoor radon concentrations. The shaded areas indicate elevations in indoor radon."[4] Source: Wisconsin Dept. of Health Services

History and Properties of Radon

History

Radon as it's known today was not actually discovered until 1900.[5] However, its effects have been historically linked to the the 16th century in the Erzgebirge, or Ore Mountains, of Germany where there was an unusually high rate of fatal lung conditions in the local ore miners.[6] Just before the turn of the century in 1896, Henri Becquerel accidentally discovered a type of radiation through experimentation with uranium salts and photographic plates. This radiation was being emitted from the salts and was causing the photo plates to develop large black spots. That radiation was later named “radioactivity” by Marie Curie.[7] Further studies in uranium and radioactivity in general eventually lead to the identification and naming of radon in 1900.

Properties

Radon is a radioactive element. It is a daughter isotope in the uranium decay series. As uranium decays it emits particles called decay products. These products consist of not only radioactive particles but specific elements. Each of these elements are also radioactive and will decay even further into other specific elements. These specific elements eventually decay into radon. The isotope uranium-238 in particular is the element that leads to the isotope radon-222.[8] This is the isotope of radon that causes problems for homeowners. It is the most common and stable isotope with a half life of 3.8 days.[9] As uranium is found naturally in the ground in rocks, soils, and dissolved in water, radon is found just as naturally.[10] Radon is naturally found in its gaseous state. It is both colorless and odorless.[11]

How does radon affect the body?

Relative to other known elements, the half life of radon is rather quick. This fast half life means an increased amount of radioactive particles is released. When this radiation is released it can cause damage to any tissues it is near. Given this high presence of radioactivity it is logical to minimize one's exposure. To determine levels of radon present in a building, it must be measured in pCi/L or "picocuries per litre." A "picocurie" is a unit used to measure amounts of radioactivity.[12] According to the National Cancer Institute, radon is present in all air.[13] If a person inhales an unsafe level of radon, their chances for developing lung cancer greatly increases. The EPA estimates that a person has a 1 in 100 chance of developing lung cancer from life-long exposure to air that contains 4 pCi/L of radon.[14]

Radon in Wisconsin

There are several counties in Wisconsin that are at higher risk for indoor radon. The Wisconsin Department of Health has information that shows that 48 of 72 Wisconsin counties report 30% or more of their results have levels of radon greater than or equal to 4 pCi/L. Some of these counties include Brown, Dane, Milwaukee, Outagamie, Waukesha, and Winnebago Counties.[15] Winnebago in particular reports that 59% of their results indicate levels above the EPA standard.[16] This is the highest percentage in the state. This information is particularly important as these counties have higher populations then other counties in Wisconsin.[17] More people means more homes and this increases the chance that a person can be affected negatively by radon.

Radon in basements

This image demonstrates how radon can get into a house.
This image demonstrates how radon can get into a house.[18] Source:Health Canada

Radon gas is released as a decay product from the radioactive decay of uranium-238 which is naturally found in the ground. Under normal circumstances this gas would just dissipate into the atmosphere. However, if a house is built in an area with higher levels of uranium in the soil, the more likely it is that radon is present and will move into the home because of pressure differences. The gas will enter through cracks in the foundation, through windows, or through a sump pump pit.[19] Over time, this radon gas can build up in the home and can eventually exceed the safety standard set by the U.S. EPA.

What can be done?

The only way to know the levels of radon in a house is to actually test for radon because it is an odorless and colorless gas.[20] According the the EPA, there are two methods to test a building for radon.[21] The first method is short term test that involves acquiring a detector. Some examples of detectors are charcoal canister detectors and charcoal liquid scintillation detectors. These detectors work over a period ranging from two to ninety days. The second method involves long terms testing. Two examples of these detectors are alpha track detectors and electret ion chambers. These detectors test over periods of more than ninety days to one year. This form of testing is more useful to gauge the average amount of radon present throughout the year.


The appropriate steps to ensure health and safety must be taken once the measurements are completed. On average, a measurement of 0.4 pCi/L of radon is normally found in the outdoor air. Average indoor radon levels are around 1.3 pCi/L.[22] If levels of 4pCi/L or more of radon are detected then it is recommended by the EPA to have a radon reduction system installed. One such system available is called a subslab depressurization system.[23] What this system does is vacuum radon gas from the surrounding soil around a property and venting it into the air through a series of PVC pipes that are installed under the basement floor. These pipes are connected to a ventilation pipe that exits near the top of the house to disburse the radon into the atmosphere. [24] Additional methods to prevent radon from entering a home include sealing cracks and construction fittings with sealant and putting an air-tight cap over the sump pump. Using these methods should help ensure radon levels are reduced to a safe degree.

References

  1. Environmental Protection Agency, "A Citizen's Guide to Radon", December 2016, https://www.epa.gov/sites/production/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf, Accessed may 2, 2017.
  2. National Cancer Institute, "Radon and Cancer," https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet, Accessed May 2, 2017.
  3. Wisconsin Dept. of Health Services, "Radon Information for Wisconsin," February 1, 2017, https://www.dhs.wisconsin.gov/radon/index.htm, Accessed May 2, 2017.
  4. Wisconsin Dept. of Health Services, "Bedrock Geology and Indoor Radon in Wisconsin," June 17, 2016, https://www.dhs.wisconsin.gov/radon/map-wis-geological.htm.
  5. C. Richard Cothern, "History and Uses," in Environmental Radon, edited by C. Richard Cothern and James E. Smith Jr. (New York, NY: Plenum Press, 1987), 32.
  6. C. Richard Cothern, "History and Uses," in Environmental Radon, edited by C. Richard Cothern and James E. Smith Jr. (New York, NY: Plenum Press, 1987), 33.
  7. Ernie Tretkoff, "March 1, 1896: Henri Becquerel Discovers Radioactivity", http://www.aps.org/publications/apsnews/200803/physicshistory.cfm, Accessed May 2, 2017.
  8. Claudio Tuniz, Radioactivity: A Very Short Introduction, (United Kingdom: Oxford University Press, 2012), 17.
  9. C. Richard Cothern, "Properties," in Environmental Radon, edited by C. Richard Cothern and James E. Smith Jr. (New York, NY: Plenum Press, 1987), 4.
  10. National Cancer Institute, "Radon and Cancer," https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet, Accessed May 2, 2017.
  11. C. Richard Cothern, "Properties," in Environmental Radon, edited by C. Richard Cothern and James E. Smith Jr. (New York, NY: Plenum Press, 1987), 1.
  12. Center for Disease Control, "What is Radon?", April 13, 2016, https://www.cdc.gov/nceh/radiation/brochure/profile_radon.htm, Accessed May 2, 2017.
  13. National Cancer Institute, "Radon and Cancer," https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet, Accessed May 2, 2017.
  14. Center for Disease Control, "What We Know About Radon," May 13, 2014, https://www.cdc.gov/cancer/dcpc/prevention/policies_practices/radon/radon.htm, Accessed May 02, 2017.
  15. Wisconsin Dept. of Health Services, “Radon Levels for Wisconsin,” February 1, 2017, http://wi-radon.info/, Accessed May 2, 2017.
  16. Wisconsin Dept. of Health services, “Winnebago County Radon Information,” February 1, 2017, http://county-radon.info/WI/Winnebago.html, Accessed May 2, 2017.
  17. United States Census Bureau, “Compare Counties for Population, Housing, Area, and Density,” 2010, https://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?src=bkmk, Accessed May 2, 2017.
  18. Health Canada, "Reducing Radon Levels in Existing Homes," http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/radon_contractors-entrepreneurs/index-eng.php, Accessed May 2, 2017
  19. U.S. Environmental Protection Agency, “A Citizen's Guide to Radon,” May 2012, https://www.epa.gov/sites/production/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf, Accessed May 2, 2017.
  20. Center for Disease Control, "What is Radon?", April 13, 2016, https://www.cdc.gov/nceh/radiation/brochure/profile_radon.htm, Accessed May 2, 2017
  21. U.S. Environmental Protection Agency, “A Citizen's Guide to Radon,” May 2012, https://www.epa.gov/sites/production/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf, Accessed May 2, 2017
  22. U.S. Environmental Protection Agency, “A Citizen's Guide to Radon,” May 2012, https://www.epa.gov/sites/production/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf, Accessed May 2, 2017
  23. U.S. Environmental Protection Agency, “Consumer's Guide to Radon Reduction,” March 2013, https://www.epa.gov/sites/production/files/2016-02/documents/2013_consumers_guide_to_radon_reduction.pdf, Accessed May 2, 2017
  24. U.S. Environmental Protection Agency, “Consumer's Guide to Radon Reduction,” March 2013, https://www.epa.gov/sites/production/files/2016-02/documents/2013_consumers_guide_to_radon_reduction.pdf, Accessed May 2, 2017

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