Radon 101 & Testing

Twa-le Abrahamson-SwanSpokane Tribal Air Quality Department

509-626-4403 twalea@spokanetribe.com

www.epa.gov/radon

Superfund Site: Midnite Uranium MineContaminants: radionuclides and heavy metals

in acid mine drainage, radioactive decay, and particulate transport in air, surface water, and groundwater.

In as soon as two years, millions of tons of contaminated material will be moved using heavy equipment. A new water treatment plant will be built. Remediation is expected to take 8 to 10 years.

https://fortress.wa.gov/doh/wtn/WTNPortal/IndicatorPages/RadSmokeLC.aspx

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

Uranium

Radium

Radon

1,600 years

4.5 billion years

3.8 days

Things to know about radonNaturally occurring GasUndetectable by human senses

◦ Colorless, Odorless, TastelessRadioactive Does not chemically reactNo static electrical charge. Will not

adhere to other atoms or surfaces.

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 SoilRadium Containing Soil

Radon Gas Spatial Distribution

Radon enters from beneath foundation and travels upward. ◦ Diluted with outdoor air

infiltrating buildingIf 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

Radon sourcesSources Curies Per Year

Emanation: Soil 2,000,000,000Ground Water 500,000,000Emanation: Oceans 30,000,000Phosphate Residues 3,000,000Uranium Tailings Piles 2,000,000Coal Residues 20,000Natural Gas 10,000Coal Combustion 900Human Exhalation 10

Why are we concerned about radon?

Radon is a known carcinogen, in the highest ranking category with tobacco products

U.S. SURGEON GENERAL HEALTH ADVISORY

“Indoor radon is the second-leading cause of lung cancer in the United States and breathing it over prolonged periods can present a significant health risk to families all over the country. It’s important to know that this threat is completely preventable. Radon can be detected with a simple test and fixed through well-established venting techniques.” – January 2005

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 is inhaled?

Alpha Decay

4He Nucleus Ejected from 222Rn Nucleus

+2

4He + 218Po

+

+

+

+

+

+

+

+

+

Radon - 222

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

Radon Progeny

218Po and 214Po deliver the radiologically significant dose to the respiratory epithelium.Lead-210

Polonium-214

Bismuth-214

Lead-214

Polonium-218

Radon-222

b,g

,g

,g

,g

b,g

Lead-206

Polonium-210

Bismuth-210b,g

,g

b,g22 yrs

4 day3 min

27 min20 min0.2 ms

5 day

138 dayStable

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 LEVELAverage indoor: 1.3 – 1.4 pCi/L

Average outdoor: 0.4 pCi/L

Testing for RadonInitial short-term test (2-7 days)

◦Closed house conditionsOne testing devicePlace in lowest lived in part of

house, ideally bedroom, living room and most frequently occupied rooms

Not a closet, bathroom, kitchen, storeroom, garage, crawlspace, attic.

Follow-up test if results are ≥ 4 pCi/L

Purpose of Test Determines Location

Lowest lived inLowest suitable for

Occupancy w/o Renovation

NO

YES

YES

• Test in livable room.

• Keep away from drafts and moisture.

Radon Measurement DevicesActivated charcoal deviceElectret Ion ChamberContinuous Radon Monitor

Activated Charcoal DevicesMeasures radonUsed by professionals and

homeownersDifferent devices have different

optimal deployment periods.Requires no power to operate.In small container (paper, metal or

plastic) containing activated charcoal.Can only be read in the lab, not in the

field.

Activated Charcoal Device ExamplesFor short-term testsMust be analyzed within 6 days

Activated Charcoal Devices

Advantages Disadvantages

Compact, convenient and economical

Can be used for 48-hour test

Can be easily mailed to lab for analysis

Passive, does not require power and silent

Quick and accurate analysis

Limited to short-term sampling

If radon peaks and valleys are dramatic, the results validity is questioned because of a possible bias over the last 12 hours.

Provides no indication of changes in radon during measurement.

Tampering detection difficult.

Electret Ion Chamber (E-Perm)Short-term and long-term

measurements2 days-1 year, dependent upon:

◦Configuration◦Type of disk used◦Anticipated radon concentration

Measuring Electret VoltagesElectrets are pre-charged by

manufacturer.Electret voltages are measured

before and after deployment.Reported radon is a function of:

Voltage drop (Approximate 2 volts drop per day per pCi/L)

Electret Ion Chambers

Advantages Disadvantages

Short-term and long-term measurements

Electret can be re-used until voltage falls below the desired operating voltage for the device used (200 volts)

Can be recharged by manufacturer ($30)

Sensitive to external gamma radiation. Correction needed.

Sensitive to altitude changes. Correction needed.

Can be damaged by touching surface, surface contamination or impact.

Pre/post voltages must be measured at the same temperature.

Continuous Radon MonitorsSun Nuclear (Solid State Silicon

Detector)◦Impacts from alpha particles are

counted.◦Data plotted and averaged◦Relatively low efficiency◦Provides continuous measurements◦Used for diagnostics

Continuous Radon Monitors

Advantages Disadvantages

Exposure variable: 48 hrs to many months

Relatively good precision

Can track hourly variations

Options to down load or print on site

Can indicate tampering or ventilation.

Higher pricedRequires trained

operatorAnnual calibrationBi-annual

performance tests.Can only test one

room at a time.

Results from a CRM

Do It Yourself Test Kits

Radon Mitigation Training

Twa-le Abrahamson-Swantwalea@spokanetribe.com

(509) 626-4403

April 8, 2014 at the US House Appropriations Committee – testifying on cuts to radon funding and services for Tribes and Environmental Justice Communities.

http://docs.house.gov/meetings/AP/AP06/20140408/101853/HHRG-113-AP06-Wstate-Abrahamson-SwanT-20140408.pdf