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@uiowa.edu Top 10 List
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
Radon Mines
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!
U.S. Radon Potential Many parts of the country have elevated radon concentrations. Map developed as basis for radon control techniques in new construction.
Insert slide here describing radon occurrence in year area of interest Radon maps can be found here: http://www.epa.gov/radon/zonemap.html
What Is Radon 222 (radon)? Radon is a gas It is naturally occurring Radon 3.8 days Radium 1,600 years Uranium 4.5 billion years You can not see or smell it It enters buildings from the soil beneath them
Average Contributions From Radon Sources In U.S. Homes Soil Gas 85-90% Water < 1% Emanation 2-5% Diffusion 1-4% Radium Containing Soil The movement of soil gas into a home is the predominant entry route. These are averages - a particular home can be different!
Radon Gas Spatial Distribution < 5 5-6 10 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.
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 222 Rn Concentrations 18 16 14 12 222 Rn (pci/l) 10 8 6 4 2 0 13 14 15 16 17 18 19 20 JUNE
Outdoor Radon in Iowa 1.5pCi /L 1.3pCi /L 1.1pCi /L 0.9pCi /L 0.7pCi /L 0.5pCi /L 0.3pCi /L National INDOOR Average 1.4 pci/l
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? Radon Decay Products Radon Radon 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.
What Happens When Radon-222 Enters a House? RDPs Radon Radon RDPs Radon enters home. Radon radioactively decays into RDPs in the air. Some RDPs remain in the air. Some RDPs plate out on surfaces.
Radon-222 α,γ Polonium-218 α,γ Lead-214 β,γ Bismuth-214 β,γ Polonium-214 α,γ Lead-210 β,γ Bismuth-210 β,γ Polonium-210 α,γ Lead-206 4 day 3 min 27 min 20 min 0.2 ms 22 yrs 5 day 138 day Stable 218 Po and 214 Po deliver the radiologically significant dose to the respiratory epithelium. Radon Progeny
Alpha α Decay + + + + + + + 4 He Nucleus Ejected from 222 Rn Nucleus +2 + + Radon - 222 4 He + 218 Po
What Happens When Radon Decay Products Are Inhaled? Double Strand Breaks Highly radioactive particles adhere to lung tissue, where they can irradiate sensitive cells. Radiation can alter the cells, increasing the potential for cancer.
Ionizing radiation can directly and indirectly damage DNA Alpha Particle Defects in tumor suppressor genes p53 Free Free radical radical formation formation Double Double strand strand DNA DNA breaks breaks At risk individuals GSTM 1 (glutathione S-transferaseS M1)
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%!!
Annual Effective Dose Equivalent to Member of the U.S. Population NCRP 93 (1987) Consumer Products Nuclear Other 3% Medicine < 1% 4% Medical X-rays 11% Other Includes: Artificial 18% Occupational 0.3% Natural (mrem) Fallout < 0.3% Radon 200 Nuclear Pow er 0.1% Miscellaneous 0.1% Cosmic 27 Terrestrial: -external 28 -internal 39 Radon 55% Artificial (mrem) -Diag. X-rays 39 -Nuc. Med. 14 Natural 82% -Consumer Pro. 10 Internal (Inside Human -Other ~1 Body) 11% TOTAL ~360 Cosmic (Outer Space) 8% Terrrestrial (Rocks & Soil) 8%
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 Waterborne radon to air ratio 10,000 : 1
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
Pipe scale Highest waterborne radon concentrations (> 10,000 pci/l) in Iowa have been attributed to radium adsorbed pipe scale.
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!
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 category International Agency for Research on Cancer
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..
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 doseresponse relationship between radon and lung cancer.
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)
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!
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
Original Scientific Basis For Radon Risk Estimates Studies on miners. Uranium miners in U.S. and other countries
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)
Adverse Health Effects Dose Response Model Linear Non-Threshold Theory Observed Effects??? Medical Patients Atomic Bomb Survivors Underground Miners Dose (rem)
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.
National Academy of Sciences BEIR 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
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/m 3 ).
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
Basement and Living Area Radon Concentrations for U.S. Residential Radon Studies. Study Location New Jersey Missouri-I Missouri-II Iowa Connecticut, Utah Southern Idaho 2 Geometric Mean (GSD) in pci/l Basement 2.4 2.4 4.6 1.5 1.8 Level 1 0.5 1.2 1.2 2.5 0.5 1.2 Level 2 0.7 1.2 1.2 2.0 0.4 1.0 1 Summary data represent those homes that were measured with no imputed (values added to replace missing values) values.
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 10% 18% 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 16%
Risk Estimates for Alternative Models (live cases and controls) Odds Ratio 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 Complete exposure WLM20 1st Story BR BR/LR LR Basement 20-39% 40-59% 60-79% 80+% Other location radon concentrations only JEAEE 12(3): 197-203, 2002
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.
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 163,510 Lung Cancer Deaths in 2005* *CA: A Journal for Clinicians - 2005 Attributed to Radon Approximately 21,000 EPA 2003
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 Annual U.S. Cancer Deaths 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 Lung Cancer (radon) Liver Cancer Brain Cancer Stomach Cancer Melanoma Oral Cancer Gallbladder Cancer Bone Cancer
Radon Induced Lung Cancer Non-Hodgkin Lymphoma Ovary Liver Esophagus Bladder Brain Kidney Stom ach M u ltip le M y e lo m a Acute Myeloid Leukem ia Melanoma Oral Cavity and Pharynx Uterine Corpus Chronic Lym phocytic Leukem ia Larynx Uterine Cervix Soft tissue Gall Bladder Thyroid Acute Lym phocytic Leukem ia Hodgkin Disease Bone and Joint S m a ll In te stin e Chronic Myeloid Leukem ia Ureter Testis Eye 5000 10000 15000 20000 Cancer Mortality per Year - United States
Is Radon a Leading Environmental Health Risk? Radon Decay Products Radon Radon
Further Information on Radon EPA 1-800-SOS-RADON http://www.epa.gov/radon/ Bill Field 319-335-4413 bill-field@uiowa.edu