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

UICThe University of Illinoisat Chicago

Great Lakes Center for Global Environmental and Occupational Health

Irina V. Dardynskaia, MD, PhDAssociate Research Professor,

Environmental and Occupational Health Sciences

Current Science on Radon and the Current Science on Radon and the Human Health Effects of RadonHuman Health Effects of Radon

SOURCES OF RADIATIONSOURCES OF RADIATION

A. NATURAL BACKGROUND RADIATIONSOURCES

B. MAN MADE BACKGROUND RADIATIONSOURCES

UIC Great Lakes Center for Global Environmental and Occupational Health

Radioactivity in NatureRadioactivity in Nature

Over 60 radionuclides can be found in nature, andthey 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


Natural Radiation SourcesNatural 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).

Terrestrial RadiationTerrestrial Radiation

Earth radioactivity

Radioactivity in water

Radioactivity in Air

Earth Radioactivity 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

Radioactivity in AirRadioactivity in Air

Produces <5% of total external terrestrial

exposure

Majority of exposure for internal is radon

Radioactivity in WaterRadioactivity in Water

All water contains some radioactivity: Sea water contains K-40 Natural springs contain U and ThRainwater picks up radioactivity from the

air.Ground water picks up radioactivity from

the soilContributor to internal doses

Cosmic Radiation Cosmic Radiation

Natural radiation originating from outside of our atmosphere

Discovered during early terrestrial experiments with weather balloons

Cosmic RadiationCosmic 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

Cosmic RadiationCosmic Radiation

Secondary

Results from the interaction of primaries

with the earth's atmosphere

Internal Emitters 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

Inhaled Radionuclides Inhaled Radionuclides

Due mostly to Radon and thoron gasRadon 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


UraniumUranium

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

URANIUMURANIUM

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.


The Uranium SeriesThe 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.

RadonRadon Properties 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


Radon 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.

Radon in ILLINOISRadon 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.

Radon map of IllinoisRadon map of Illinois

Radon zones

.

Zone 1 Highest Potential (greater than 4 pCi/L)

Zone 2 Moderate Potential (from 2 to 4 pCi/L)

Zone 3 Low Potential (less than 2 pCi/L)

Radon gets in throughRadon gets in through

1. Cracks in solid floors2. Construction joints3. Cracks in walls4. Gaps in suspended floors5. Gaps around service pipes6. Cavities inside walls7. The water supply

Other Entry Point of RadonOther 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.

Radon in the HouseRadon 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.

Health effects of radon 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.

Health effects of radon 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.

Health effects of radonHealth effects of radon

Information on radon carcinogenesis comes from molecular, cellular, animal and human ( or epidemiologic ) studies

History 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

Epidemiological data on Epidemiological data on radonradon

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

Cancer effects of radon 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

Health Effects of Radon Health Effects of Radon

The National Research Council's report of the sixthCommittee on Biological Effects of IonizingRadiations (BEIR VI) addresses the risk of lungcancer associated with exposure to Radon and itsradioactive progeny.According to the National Academy of Science'sSixth Committee data Radon is a Class A humancarcinogen which means there is an actual evidencethat exposure to radon causes lung cancer in humans,and the second leading cause of lung cancer in the U.S.

Health Effects of Radon 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.

Extrapolation of risks at higher Extrapolation of risks at higher exposures to lower exposuresexposures 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

Extrapolation of risks at higher Extrapolation of risks at higher exposures to lower exposuresexposures to lower exposuresCorroborating 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

Radon and SmokingRadon 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.

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


100 times the risk of dying in a home fire

Fix your home


Fix your home


100 times the risk of dying in an airplane crash

Fix your home


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)

RADONRADON

Chronic EffectsChronic Effects (Noncancer)(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.


Radon Measurement Radon Measurement Protocols Protocols

IDNS Adopted Rule for Radon Measurement Protocols

““Action Level" for Indoor Action Level" for Indoor RadonRadon

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.

Working level (WL) and Working level (WL) and working level months (WLM) working level months (WLM)

definitiondefinitionAny 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

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

Documents

mremyr cosmic radiation

occupational health

air slide

mremyr sandstone

mremyr limestone

mremy slide

national average

mremyr exposure dependent