Radon in ns

Helen Mersereau, MHSc

Cape Breton University

Funded by Nova Scotia WCB and WorkSafeBC

Uranium (U)Silver/gray metallic element70% more dense than leadFound in most rocks, earth’s crust and seawaterWeakly radioactiveDecays slowly, producing radon

Radon (Rn)Radioactive gasFound in soil, rock, waterInvisible, odourless, tastelessOccurs naturally due to decay of uraniumDecays further itself, emitting ionizing radiation

Radon (Rn)Moves freely through soilOne of the heaviest gases under normal pressureEscapes to atmosphere or into buildingsIn outside atmosphere is diluted to insignificant amountsIn confined or poorly ventilated areas of buildings it can accumulate to high levels, especially in the low lying areas.

How does radon accumulate?Building is built over bedrock or soil that contains uraniumAir pressure in home is lower than surrounding soilSeeps in through:

Cracks in foundation/wallsWindowsFloor drains and sumpsAnywhere there is an opening where the building contacts the soil

Aspirates from water (treatment, showers, etc.)

water treatment plants are a concern

Why is radon a concern?Affects Indoor Air Quality (IAQ) worldwideCauses an estimated 21,000 lung cancer deaths per year in US2nd most frequent cause of lung cancer after cigarette smoking8 to 15% of lung cancer is caused by radon6th leading cause of cancer overallA smoker who is exposed to radon has a much higher risk of lung cancer (5-20x greater) –synergistic effect14% of people who die from radon-related lung cancer have never smoked

Why is Radon a concern in NS?

Nova Scotia has been identified to have higher than the national average of lung cancerNova Scotia has been identified to have higher than the average radon level (geology based granite)NS also has high rates of smoking, which can act synergistically with radon to increase rates of lung cancer

How does radon cause cancer?Because it is radioactive, radon decaysProduces decay products, sometimes called “radon daughters” or “radon progeny”Two of these progeny decay rapidly themselves, and emit alpha particles. When alpha particles hit an object, the energy in them is absorbed by the surface of the object.Human skin is thick enough to not be affectedIf you breathe in alpha particles, they can damage bronchial and lung tissue, and can lead to lung cancer.

Radon and Lung Cancer RiskExposureLevel Bq/m3

Non smokerAdditional Risk

SmokerAdditional Risk

200 2% 17%

400 3% 22%

800 5% 30%

How is radon testing done?Radioactivity or the strength of a radioactive source is measured in units of Becquerel (Bq). 1 Bq = 1 event of radiation emission per second.Radon is measured in terms of Becquerel per cubic meter (Bq/m3)May take long term measurements: (3 mos.–1 yr.) or short term measurements (less than 3 mos.)Long term more effective at attaining true valuesAlpha Track Detection

Monitors

Measurement Locations in Public BuildingsTaken From the Health Canada Protocols

Preferred device locations should be:By an interior wall at breathing level, but at least 50 cm from ceiling.Where occupants spend much of their time.In occupied rooms in basements or the floor with the lowest level occupied rooms in the building.In rooms above crawl spaces, over slabs or built into the side of a hill with walls that may be in contact with the earth.

Measurement Locations in Public Buildings(continued)

Devices should not be placed:In bathrooms, closets, cupboards, sumps, crawl spaces or nooks because relatively little time is spent thereNear air currents caused by heating, ventilation, doors, windows or fans. Near heat, such as over radiators or in direct sunlightNear electrically powered equipment or appliances

Radon guidelines2006 Health Canada dropped acceptable concentration of radon from 800 to 200 Bq/m3

If >200 Bq/m3, remedial action should be takenresponse time decreases with increasing levels found200 to 400, 2 years to fix400 to 600, 1 year to fix600 to 800, 6 months to fix

Radon levels should be reduced to a value as low as practicable

New dwellings should use techniques that minimize radon entry and make future removal of radon easier.

Radon mitigationSoil SuctionSealing cracks and openingsPressurizationEliminate Radon in waterHeat Recovery Ventilator

Cape Breton University Study

funding received from WorksafeBC and WCB of Nova Scotia

part of reason for funding was NS has high levels of naturally occurring radon

200 radon monitors put in workplaces in Nova Scotia

What about workplaces?

WorkSafe BC and Nova Scotia WCB approached for funding of workplace radon in NS

Received funding for 200 radon alpha detectorsContacted workplace partnersPut on education sessions for JOHSCPut monitors in place for 3 month periods at selected NS workplacesResults communicated directly to participants with advice for remediation

Radon Sampling Locations

Nova Scotia

Radon Sampling Locations

Cape Breton

NS Workplace ResultsLocation Range of Results (Bq/m3) Average Result (Bq/m3)

Sydney 17.8 – 98.7 34.6Lingan 10.4 – 38.5 20.3

Wreck Cove 7.9 – 18.5 12.2Neil’s Harbour 10.4 – 16.8 13.8

Cheticamp 8.9 – 21.1 15.9Inverness 8.5 – 14.1 11.8

Port Hawkesbury 5.4 – 19.3 10.6Pt. Aconi 17.8 – 50.9 29.5Trenton 5.3 – 15.0 8.3

Lakeside 6.6 – 83.1 30.0Dartmouth 7.6 – 48.0 17.7

St. Margaret’s Bay 42.5 – 174.4 99.1Glace Bay 14.4 – 94.9 54.1Louisbourg 12.2 – 25.2 17.3

North Sydney 15.9 – 61.1 28.4Coxheath 64.4 – 208.0 104.5

Workplace Findings

Some workplaces were concerned about participating, unsure of how to deal with resultsOnly one workplace had levels above 200 Bq/m3, and then with only 2 of their 10 monitors, average was acceptableOne other workplace had levels above the 150 Bq/m3 action level.All other workplaces were acceptable

Additional CB Residential Survey

Monitors provided to residents3 month survey periodResults reported to individual residents in a confidential manner (researcher blinded to location other than postal code)Advice given regarding Health Canada Standard and mitigation information

Crack fill, positive pressure, etc.

Findings

Results indicate 3 out of 20 need some form of radon mitigation, above 200 Bq/m3

Indicates need for follow sampling in Howie Centre and Bras D’or5 out of 20 are above action limit of 150 Bq/m3

CB Residential Results (20)Location/Cape

BretonRange of Results (Bq/m3) Average Result (Bq/m3)

Sydney 12.4 – 156.8 90.6Glace Bay 14.8 – 69.9 47.4

Howie Centre 35.2 – 528.8 221.2Port Morien 17.7 17.7Bras D’or 47.3 – 381.1 214.2Big Pond 33.6 – 117.1 75.4

North Sydney 18.3 18.3

Concerns

What happens if the results are high?Is funding available to help with mitigation costs?Who can help with mitigation design?Will the resident have to disclose radon information if selling house?Will radon affect home resale value?

ConclusionRadon is a carcinogenic, naturally occurring gas that is ubiquitous in the environmentSeeps into buildings through cracks and other openings when air pressure is low insideExposure to levels of radon over 200 Bq/m3 for an extended period should be avoided, especially if you’re a smokerNew and existing homes and buildings should be tested for radon and if unacceptable levels are found, mitigation should be commenced

Thanks

To WCB NSTo WorksafeBCTo safety services NS for invitation to speakTo you for listening!

Questions?