1. UIC The University of Illinois at Chicago Great Lakes Center for Global Environmental and Occupational Health Irina V. Dardynskaia, MD, PhD Associate Research Professor, Environmental and Occupational Health Sciences

2. Current Science on Radon and the Human Health Effects of Radon

3. SOURCES OF RADIATION SOURCES OF RADIATION A. NATURAL BACKGROUND RADIATION SOURCES B. MAN MADE BACKGROUND RADIATION SOURCES UIC Great Lakes Center for Global Environmental and Occupational Health

4. Radioactivity in Nature Over 60 radionuclides can be found in nature, and they can be placed in three general categories: Primordial - from before the creation of the Earth Cosmogenic - formed as a result of cosmic ray interactions Human produced - enhanced or formed due to human actions UIC Great Lakes Center for Global Environmental and Occupational Health

5. Natural Radiation Sources Terrestrial Radiation (U.S. national average is 28 mrem/yr) Cosmic Radiation (U.S. national average is 27 mrem/yr) Internal Emitters (Food Chain-U.S. National average is 39 mrem/yr) Inhaled Radionuclides (U.S. national average is 200 mrem/yr).

6. Terrestrial Radiation Earth radioactivity Radioactivity in water Radioactivity in Air

7. Earth Radioactivity Source: small amounts of radioactive material found in rock and soil. Major isotopes: Uranium and Thorium Exposure dependent on location: Atlantic and Gulf coastal = 15-35 mrem/yr, Colorado Plateau = 75-140 mrem/yr Exposure dependent on type of soil: Volcanic - 125 mrem/yr; Sandstone - 50 mrem/yr; Limestone –25 mrem/y

8. Radioactivity in Air Produces <5% of total external terrestrial exposure Majority of exposure for internal is radon

9. Radioactivity in Water All water contains some radioactivity: Sea water contains K-40 Natural springs contain U and Th Rainwater picks up radioactivity from the air. Ground water picks up radioactivity from the soil Contributor to internal doses

10. Cosmic Radiation Natural radiation originating from outside of our atmosphere Discovered during early terrestrial experiments with weather balloons

11. Cosmic Radiation Primary Galactic Cosmic Rays from outside the solar system Geomagnetically Trapped When galactic rays approach earth, they must have enough energy to pass through magnetic fields If they lack enough energy, they become trapped in two energy bands Solar Cosmic Rays Produced by severe solar flares

12. Cosmic Radiation Secondary Results from the interaction of primaries with the earth's atmosphere

13. Internal Emitters Results from the transfer of natural radiation from the food chain to man Deposited internally from trace amounts found in soil, water and air Isotopes: Primary - K-40; others - Rb-87, Ra-226, U-238, Po-210, C-14

14. Inhaled Radionuclides Due mostly to Radon and thoron gas Radon is a product of the U-238 Series: U- 238 Th-234 Pa-234 U-234 Th-230 Ra-226 Rn-222 Thoron is a product of the Th-232 series:Th-232 Ra-228 Ac-228 Th-228 Ra- 224 Rn-220 UIC Great Lakes Center for Global Environmental and Occupational Health

15. Uranium Uranium-238, a radioactive metal, is present in rocks, soil, and throughout the environment. Uranium-238 decays to form radium-226, which has a half-life of 1,600 years. Radium-226 then decays to form radon-222 gas, which has a half-life of 3.8 day. Exposure to uranium can occur through the air, with an average daily intake estimated to be 0.0007 to 0.007 pCi/d. Higher levels of exposure generally occur through food consumption, with average levels of 0.72 to 1.0 pCi/d, or through the drinking water, with average levels of 0.6 to 2.0 pCi/d. Uranium is present all over. Daughter products diffuse to the surface. These gases attach themselves to dusts and aerosols which are inhaled

16. URANIUM Natural uranium is a silver-colored radioactive metal that contains three forms (isotopes) of uranium.: uranium- 236,uranium-235, and uranium-238. The chemical symbol for uranium is U, and it has atomic weight of 238.03 g/mol. Uranium-238, a fairly abundant radioisotope in the Earth's crust (it has an extremely long half-life---about 4.5 billion years). Uranium-238 decays to radium-226. Both these materials are solids, so they are immobile in soil. Radium-226 has a half-life of about 1600 years; it decays to radon-222, a gas. UIC Great Lakes Center for Global Environmental and Occupational Health

17. The Uranium Series Here are the Radioactive Byproducts of Depleted Uranium (Uranium-238) The chart given below lists all of the decay products of uranium-238 in their order of appearance.

19. Radon Properties Radon is a colorless, odorless, tasteless, radioactive gas that is formed from the radioactive decay of uranium. The chemical symbol for radon is Rn, and it has an atomic weight of 222 g/mol. Radon is an alpha -particle emitter that decays with the half-life of 3.8 days into a short-lived series of progeny The short -lived radon progeny are Polonium-218, Lead-214, and Bismuth-214 UIC Great Lakes Center for Global Environmental and Occupational Health

20. Radon Radon concentrations are based on amounts of U and Th in the area. High Areas: Colorado (Grand Junction) - mine tailings. Most has been removed; Pennsylvania - High radium concentration; Underground mines, caves, caverns, etc.

21. Radon in ILLINOIS Radon in ILLINOIS The U.S. EPA and the U.S. Geological Survey have evaluated the radon potential in the U.S. and have developed this map is to assist National, State, and local organizations to target their resources and to assist building code officials in deciding whether radon-resistant features are applicable in new construction. This map is not intended to be used to determine if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones. All homes should be tested regardless of geographic location. The map assigns each of the 3,141 counties in the U.S. to one of three zones based on radon potential. Each zone designation reflects the average short-term radon measurement that can be expected to be measured in a building without the implementation of radon control methods. The radon zone designation of the highest priority is Zone 1.

22. Radon map of Illinois Radon zones. Zone 1Highest Potential (greater than 4 pCi/L) Zone 2Moderate Potential (from 2 to 4 pCi/L) Zone 3Low Potential (less than 2 pCi/L)

23. Radon gets in through 1. Cracks in solid floors 2. Construction joints 3. Cracks in walls 4. Gaps in suspended floors 5. Gaps around service pipes 6. Cavities inside walls 7. The water supply

24. Other Entry Point of Radon One other radon entry point is through the water supply. Radon is water-soluble, so groundwater probably has some radon gas dissolved in it.

25. Radon in the House Once in the house, the radon decays to polonium-218 and then to radioactive lead (radon has a half-life of about 4 days; polonium and lead-214 have half lives of minutes). Polonium-218 and lead-214 are radon daughter products (RDP), and they are solids, so they exist as aerosol particles.

26. Health effects of radon Humans may receive exposure to radon through water or air that is injected. Because radon is a vapor, it can be inhaled. Radon is is chemically inert and electrically uncharged When radon progeny are formed they are electrically charged and can attach themselves to tiny dust particles in indoor air The dust particles can also be easily be inhaled into the lungs and can adhere to the lining of the lung The deposited atoms decay, or change by emitting a type of radiation called alpha radiation, which has potential to damage cells in the lung.

27. Health effects of radon Alpha radiation can disrupt DNA of lung cells The DNA damage has the potential to be one step in the chain of events that can lead to cancer Alpha radiation travel only extremely short distances in the body.Thus, alpha radiation from radon and decay of radon progeny in the lungs cannot reach cells in any other organs, so its likely that lung cancer is only potentially important cancer hazard posed by radon in indoor air.

28. Health effects of radon Information on radon carcinogenesis comes from molecular, cellular, animal and human ( or epidemiologic ) studies

29. History An “unknown” lung disease in the miners in the 1400’s Identified in 1879 in autopsies of European miners as lung cancer ( Lymphosarcoma) By 1920 it was realized that in Joachimsthal miners ( Czechslovakia) the same disease was present accounting for up to 40 per cent of miners deaths. The epidemiological studies began in 1946 About 1946, extensive uranium ore deposits were discovered in Colorado plateau area

30. Epidemiological data on radon The recently reported analyses by Lubin and colleagues of data from 11 studies of underground miners--uranium miners in Colorado, New Mexico, France, Australia, the Czech Republic, and Canada; metal miners in Sweden; tin miners in China; and fluorspar miners in Canada covered a wide range of mining environments, times, and countries. The analysis involved a total of 68,000 miners and to date, 2,700 deaths from lung cancer. Radon has been conclusively shown in these studies of underground miners to cause lung cancer

31. Cancer effects of radon There is also supporting evidence from experimental studies of animals that confirm radon and its progeny as a cause of lung cancer The molecular and cellular studies provide an understanding of the mechanisms by which radon and its progeny cause lung cancer. The cellular and molecular evidence was central to the specification of the risk model The linear nonthreshold was used in description of relation between lung cancer risk and radon exposure

32. Health Effects of Radon The National Research Council's report of the sixth Committee on Biological Effects of Ionizing Radiations (BEIR VI) addresses the risk of lung cancer associated with exposure to Radon and its radioactive progeny. According to the National Academy of Science's Sixth Committee data Radon is a Class A human carcinogen which means there is an actual evidence that exposure to radon causes lung cancer in humans, and the second leading cause of lung cancer in the U.S.

33. Health Effects of Radon In addition to NRC and USEPA, radon’s risk is recognized by the American Medical Association, US Center for Disease Control, WHO, American Lung Association, etc. Not everyone exposed to elevated levels of radon will develop lung cancer. The amount of time between exposure and the onset of the disease may be many years.

34. Extrapolation of risks at higher exposures to lower exposures Average exposures received by the miners in epidemiologic studies are about one order of magnitude higher than average indoor exposures, although the lowest exposures of some miners overlap with some of the highest indoor exposures The BEIRVI committee selected a linear-nonthreshold relationship relating exposure to risk for the relatively low exposures at issue for indoor radon. Support for this assumption came primarily from the committee’s review of the mechanistic information on alpha-particle-induced carcinogenesis

35. Extrapolation of risks at higher exposures to lower exposures Corroborating information included evidence for linearity in the miner studies at the lower range of exposures, and the linearity and magnitude of risk observed in the meta-analysis of the case-control studies, which was fully consistent with extrapolation of miner data

36. Radon and Smoking For persons who smoke, the health risk associated with elevated radon levels is especially high due to a synergistic interaction between smoking and radon.

37. Radon Level If 1000 people who smoked were exposed to this level over a lifetime … The risk of cancer from radon exposure compares to... What to do: Stop smoking and... 20 pCi/L About 135 people could get lung cancer 100 times the risk of drowing Fix your home 10 pCi/L About 71 people could get lung cancer 100 times the risk of dying in a home fire Fix your home 8 pCi/L About 57 people could get lung cancer Fix your home 4 pCi/L About 29 people could get lung cancer 100 times the risk of dying in an airplane crash Fix your home 2 pCi/L About 15 people could get lung cancer 2 times the risk of dying in a car crash Consider fixing between 2 and 4 pCi/L 1.3 pCi/L About 9 people could get lung cancer (Average indoor radon level) (Reducing radon levels below 2 pCi/L is difficult) 0.4 pCi/L About 3 people could get lung cancer (Average outdoor radon level)

38. RADON Chronic Effects (Noncancer) Chronic exposure to radon in humans and animals via inhalation has resulted in respiratory effects (chronic lung disease, pneumonia, fibrosis of the lung), while animal studies have reported effects on the blood and a decrease in body weights. UIC Great Lakes Center for Global Environmental and Occupational Health

39. Radon Measurement Protocols IDNS Adopted Rule for Radon Measurement Protocols

40. “Action Level" for Indoor Radon The EPA has established an "action level" for indoor radon of 4 picocuries per liter (pCi/l) and a procedure for testing homes, schools and commercial buildings. Nearly one out of every 15 homes in the U.S. is estimated to have radon levels that exceed this level.

41. Working level (WL) and working level months (WLM) definition Any combination of radon and radon daughters in 1 liter of air that will result in the emission of 1.3 x 10 -5 megaelectron volts of alpha particle energy. Working level month ( WLM) one working level incurred over 170 working levels BEIR 1980 and other sources indicate that 1 WLM equals 0.4-0.8 rad