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Residential Radon Exposure – A Leading Environmental Health Risk: Why we need to take action in Minnesota!
Don MaileyRE/MAX Results
c (952) 212-0968
What Is Radon?What Is Radon?• Radon is a gas
• It is naturally occurring
• You can not see or smell it
• It enters buildings from the soil beneath them
Uranium
Radium
Radon
MN Radon Potential MN Radon Potential
Zone 1
Highest Potential (greater than 4 pCi/L)
Zone 2
Moderate Potential (from 2 to 4 pCi/L)
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 and schools in MN, as well as workplaces!
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!
Water< 1%
Soil Gas85 - 90%
Diffusion1 - 4%
Emanation2 - 5%
Radium Containing SoilSoil Containing Radium
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.
10
< 5
5-6
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
• 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?
Residential Radon Exposure – A Leading Environmental Health Risk:
What is the Evidence?
WHAT IS THE EVIDENCE #2
Outdoor radon exposure can be significant!
Outdoor 222Rn Concentrations
JUNE
13 14 15 16 17 18 19 20
222
Rn (p
Ci/L
)
0
2
4
6
8
10
12
14
16
18
Outdoor Radon Levels
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!
Why Is Radon A Concern?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.
Radon Decay Products
Radon
Radon
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.Radon
Radon
RDPsRDPs
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
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 Minnesotan, it represents well over 65%!!
Annual Effective Dose Equivalent to Member of the U.S. Population
NCRP 93 (1987)
Other< 1%
Radon55%
Consumer Products
3%Nuclear Medicine
4%
Cosmic(Outer Space)
8%
Terrrestrial(Rocks & Soil)
8%
Internal(Inside Human
Body)11%
Medical X-rays11%
Other Includes: Occupational 0.3% Fallout < 0.3% Nuclear Pow er 0.1% Miscellaneous 0.1%
Natural 82%
Artificial 18% Natural (mrem)Radon 200Cosmic 27
Terrestrial: -external 28-internal 39
Artificial (mrem)-Diag. X-rays 39-Nuc. Med. 14-Consumer Pro. 10-Other ~1
TOTAL ~360
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!
Waterborne Radon
Primarily from groundwater sources (wells) rather than rivers
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!
“Radon Is A Serious National Health Problem”
“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…..
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
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 categoryInternational Agency for Research on Cancer
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.
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!
Original Scientific Basis For Radon Risk Estimates
Original Scientific Basis For Radon Risk Estimates
• Studies on miners.
–Uranium miners in U.S. and other countries
EPIDEMIOLOGIC MINER STUDIESChina (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)
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 EPA’s action level of 4 pCi/L (150 Bq/m3).
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!
LUNG CANCER DEATHS Per Year
Estimated 172,000 Lung Cancer Deaths in 2008*
Attributed to RadonApproximately 21,000 EPA 2008
*CA: A Journal for Clinicians - 2008
Should we be concerned about radon-induced lung cancer given that the risk pales in comparison to the
risk posed by smoking?
Comparing Radon Related Cancer to Other Cancer Types
02000400060008000
100001200014000160001800020000
An
nu
al U
.S. C
an
cer
De
ath
s
Lung Cancer (radon)
Liver Cancer
Brain Cancer
Stomach Cancer
Melanoma
Oral Cancer
Gallbladder Cancer
Bone Cancer
Comparing Radon Related Cancer to Other Cancer Types
Cancer Mortality per Year - United States5000 10000 15000 20000
EyeTestisUreter
Chronic Myeloid LeukemiaSmall IntestineBone and Joint
Hodgkin DiseaseAcute Lymphocytic Leukemia
ThyroidGall Bladder
Soft tissueUterine Cervix
LarynxChronic Lymphocytic Leukemia
Uterine CorpusOral Cavity and Pharynx
MelanomaAcute Myeloid Leukemia
Multiple MyelomaStomach
KidneyBrain
BladderEsophagus
LiverOvary
Non-Hodgkin LymphomaRadon Induced Lung Cancer
Is Radon a Leading Environmental Health Risk ?
Radon Decay Products
Radon
Radon
Why are the hazards of radon 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
Further Information on Radon
EPA 1-800-SOS-RADONhttp://www.epa.gov/radon/
Bill Field [email protected]
Special Thanks To:R. William Field, Ph.D., M.S.
Associate ProfessorDepartment of Occupational and Environmental Health
Department of EpidemiologyCollege of Public Health
104 IREHUniversity of Iowa
Iowa City, IA [email protected]