Residential Radon Exposure A Leading Environmental Health Risk: Why we need to take action in insert

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Residential Radon Exposure A Leading
Environmental Health Risk Why we need to take
action in (insert your region)?

• R. William Field, Ph.D., M.S.
• Associate Professor
• Department of Occupational and Environmental
  Health
• Department of Epidemiology
• College of Public Health
• 104 IREH
• University of Iowa
• Iowa City, IA 52242
• Bill-field_at_uiowa.edu

Top 10 List
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Why is the evidence ignored or not accepted ??

• Invisible, odorless, colorless
• Naturally occurring (no villains)
• Can not link deaths to radon exposure
• Long latency period
• Not a dread hazard
• Cancers occur one at a time
• Voluntary risk
• Lack of press no sensational story
• No sensory reminders to repetitively stimulate
• us to think about it
• Lung cancer does not occur in children

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Radon Mines
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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 1

• There is widespread potential for radon exposure
  in homes coast to coast as well as workplaces!

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U.S. Radon Potential

• Many parts of the country have elevated radon
  concentrations.
• Map developed as basis for radon control
  techniques in new construction.

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Insert slide here describing radon occurrence in
year area of interest

• Radon maps can be found here
• http//www.epa.gov/radon/zonemap.html

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What Is Radon 222 (radon)?

• Radon is a gas
• It is naturally occurring
• You can not see or smell it
• It enters buildings from the soil beneath them

3.8 days
1,600 years
4.5 billion years
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Average Contributions From Radon Sources In U.S.
Homes

• The movement of soil gas into a home is the
  predominant entry route.
• These are averages - a particular home can be
  different!

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Radon Gas Spatial Distribution

• Radon enters from beneath foundation and travels
  upward.
• Diluted with outdoor air infiltrating building
• If radon is less than 4 pCi/L in lower level, one
  can say with reasonable confidence that upper
  floors are also less than 4 pCi/L.

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Occupational Exposure to Radon Very Common

• Mine workers, including uranium, hard rock, and
  vanadium
• Workers remediating radioactive contaminated
  sites, including uranium mill sites and mill
  tailings
• Workers at underground nuclear waste repositories
  
• Radon mitigation contractors and testers
• Employees of natural caves
• Phosphate fertilizer plant workers
• Oil refinery workers
• Utility tunnel workers

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• Subway tunnel workers
• Construction excavators
• Power plant workers, including geothermal power
  and coal
• Employees of radon health mines
• Employees of radon balneotherapy spas (waterborne
  222Rn source)
• Water plant operators (waterborne 222Rn source)
• Fish hatchery attendants (waterborne 222Rn
  source)
• Employees who come in contact with
  technologically enhanced sources of naturally
  occurring radioactive materials
• Incidental exposure in almost any occupation from
  local geologic 222Rn sources
• Plowing?

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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 2

• Outdoor radon exposure can be significant!

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Outdoor 222Rn Concentrations
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Outdoor Radon in Iowa
National INDOOR Average 1.4 pCi/L
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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 3

• Alpha particles are very
• effective at causing DNA
• damage!

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Why Is Radon A Concern?

• Radon decays into radioactive particles known as
  radon decay products.
• These particles are easily inhaled and deposited
  in the lungs where they can damage sensitive lung
  tissue.

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What Happens When Radon-222 Enters a House?

• Radon enters home.
• Radon radioactively decays into RDPs in the air.
• Some RDPs remain in the air.
• Some RDPs plate out on surfaces.

RDPs
RDPs
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Radon Progeny
218Po and 214Po deliver the radiologically
significant dose to the respiratory epithelium.
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Alpha ? Decay
4He Nucleus Ejected from 222Rn Nucleus
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What Happens When Radon Decay Products Are
Inhaled?

• Highly radioactive particles adhere to lung
  tissue, where they can irradiate sensitive cells.
• Radiation can alter the cells, increasing the
  potential for cancer.

Double Strand Breaks
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Ionizing radiation can directly and indirectly
damage DNA
Free radical formation
Alpha Particle
Double strand DNA breaks

• Defects in tumor suppressor genes p53

At risk individualsGSTM1 (glutathione
S-transferase M1)
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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 4

• For the average individual in the United States
  Radon decay products (radon) deliver over 50 of
  our average radiation dose! For the average,
  Iowan it represents well over 75!!

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Annual Effective Dose Equivalent to Member of the
U.S. Population NCRP 93 (1987)
Natural (mrem) Radon 200 Cosmic
27 Terrestrial -external 28 -internal
39 Artificial (mrem) -Diag. X-rays 39 -Nuc.
Med. 14 -Consumer Pro. 10 -Other 1 TOTAL
360
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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 5

• Waterborne radon also contributes to our overall
  radon exposure!

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Waterborne Radon

• Primarily from groundwater sources (wells) rather
  than rivers
• Waterborne radon to air ratio
• 10,000 1

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Proposed Waterborne Radon Standard

• EPA proposed new regulations November 2, 1999 (64
  FR 59246).
• 300 pCi/L standard for public water supplies
• Multimedia Mitigation (MMM) programs -- while
  individual water systems reduce radon levels in
  drinking water to 4,000 pCi/L or lower

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Pipe scale

• Highest waterborne
• radon concentrations
• (gt 10,000 pCi/L) in Iowa have been
• attributed to radium
• adsorbed pipe scale.

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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 6

• National and International Public Health Agencies
  support the contention that radon is a leading
  environmental
• health risk!

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EPA Surgeon General Recommend
Take action if a home is at or above 4.0 pCi/L
(year long average) 4.0 pCi/L EPA ACTION
LEVEL Average indoor 1.3 1.4 pCi/L Average
outdoor 0.4 pCi/L
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How Does Radon Rank As A Cancer Causing Agent?

• Radon is ranked as a Group A carcinogen
• Highest ranking for cancer potential
• Known to cause cancer in humans
• Tobacco smoke and tobacco products in same
  category

International Agency for Research on Cancer
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Radon Is A Serious National Health Problem

• American Lung Association
• American Medical Association
• Environmental Protection Agency
• National Academy of Sciences
• National Council on Radiation Protection and
  Measurement
• U.S. Surgeon General
• World Health Organization, and others..

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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 7

• Laboratory studies using different species of
  radon-exposed animals clearly show a linear dose-
  response relationship between radon and lung
  cancer.

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Animal Studies

• Confirm carcinogenicity of radon.
• Exposure to ore dusts and diesel fumes,
  simultaneously with radon, did not increase
  incidence of lung cancer above that produced by
  radon progeny exposures alone. (DOE/OER 1988)

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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 8

• Studies of occupationally-exposed miners clearly
  show a linear relationship between radon exposure
  and lung cancer!

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Early Radon Related Epidemiology

• 1556 Agricola - Miners in Europe
• 1879 Harting Hesse - Lung Cancer in Miners
• 1921 Uhlig - Radium Emanations Lung Cancer
• 1950s Peller - First Review of Mining Related
  Cancers
• 1970s (ongoing) Studies of Underground Miners

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Original Scientific Basis For Radon Risk Estimates

• Studies on miners.
• Uranium miners in U.S. and other countries

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EPIDEMIOLOGIC MINER STUDIES

• China (Tin Miners)
• Czechoslovakia (Uranium)
• Colorado (Uranium)
• Ontario (Uranium)
• Newfoundland (Florspar)
• Sweden (Iron)
• New Mexico (Uranium)
• Beaverlodge (Uranium)
• Port Radium (Uranium)
• Radium Hill (Uranium)
• France (Uranium)

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Dose Response Model
Linear Non-Threshold Theory
Atomic Bomb Survivors
Observed Effects
Underground Miners
Medical Patients
Adverse Health Effects
? ? ?
Dose (rem)
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Occupational Miner Studies

• Linear dose response relationship was found for
  all the occupational studies.
• A 1994 NCI pooled analyses of 68,000 miners
  concluded that about 39 of the lung cancer
  deaths among smokers and 73 of the lung cancer
  deaths among never-smokers may have been due to
  their occupational radon progeny exposure.
• Projecting risks to the residential setting they
  concluded that radon progeny may be responsible
  for 10 12 of lung cancers in smokers and 28
  -31 in never-smokers.

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National Academy of SciencesBEIR VI 1999

• Risk estimates based primarily on radon-exposed
  miners
• Estimated 18,600 lung cancer deaths each year in
  the U.S. from residential radon exposure

EPA Estimates 21,000
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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 9

• Case-control studies of individuals exposed to
  radon in their homes show an increased lung
  cancer risk even at or below the EPAs action
  level of 4 pCi/L (150 Bq/m3).

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N. American Pooling

• __________________________________________________
  _________
• Study Cases Controls
• __________________________________________________
  _________
• New Jersey 480
  442
• Winnipeg 738
  738
• Missouri - I 618
  1,402
• Missouri II 697
  700
• Iowa 413
  614
• Connecticut 963
  949
• Utah/S. Idaho 511
  862
• _______________________________________
• Total 4,420
  5,707

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Basement and Living Area Radon Concentrations
for U.S. Residential Radon Studies.
1Summary data represent those homes that were
measured with no imputed (values added to replace
missing values) values.
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International Pooling of Residential Radon
Case-Control Studies

• New Jersey, Missouri I, Canada, Iowa, Missouri
  II, a combined study from Connecticut, Utah and
  S. Idaho
• Shenyang, China, Stockholm, Sweden, Swedish
  nationwide, Winnipeg, Canada, S. Finland, Finnish
  nationwide, SW England, W. Germany, Sweden, Czech
  Republic, Italy-Trento, Spain, Austria, France,
  China - Gansu Province, E. Germany

10 18
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Risk Estimates for Alternative Models
(live cases and controls)
Complete exposure
Other location radon concentrations only
20-39
40-59
60-79
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JEAEE 12(3) 197-203, 2002
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Iowa Study Summary

• The findings suggest that prolonged
• exposure to radon, even at 4 pCi/L,
• increases lung cancer risk.
• These findings indicate that radon is a major
  environmental carcinogen.

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Residential Radon Exposure A Leading
Environmental Health Risk What is the
Evidence?WHAT IS THE EVIDENCE 10

• Radon exposure represents a major source of
  cancer mortality in the United States!

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LUNG CANCER DEATHS Per Year

• Estimated 163,510 Lung Cancer Deaths in 2005
• Attributed to Radon
• Approximately 21,000 EPA 2003

CA A Journal for Clinicians - 2005
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• Should we be concerned about radon-induced lung
  cancer given that the risk pales in comparison to
  the risk posed by smoking?

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Comparing Radon Related Cancer to Other Cancer
Types
Lung Cancer (radon)
20000
Liver Cancer
18000
16000
Brain Cancer
14000
Stomach Cancer
12000
Annual U.S. Cancer Deaths
10000
Melanoma
8000
Oral Cancer
6000
4000
Gallbladder Cancer
2000
Bone Cancer
0
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Is Radon a Leading Environmental Health Risk ?
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Further Information on Radon

• EPA 1-800-SOS-RADON
• http//www.epa.gov/radon/
• Bill Field 319-335-4413
• bill-field_at_uiowa.edu