Radon in
ns
Helen Mersereau, MHSc
Cape Breton University
Funded by Nova Scotia WCB and WorkSafeBC
Uranium (U)
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Silver/gray metallic
element
70% more dense than
lead
Found in most rocks,
earth’s crust and
seawater
Weakly radioactive
Decays slowly,
producing radon
Radon (Rn)
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Radioactive gas
Found in soil, rock,
water
Invisible, odourless,
tasteless
Occurs naturally due to
decay of uranium
Decays further itself,
emitting ionizing
radiation
Radon (Rn)
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Moves freely through soil
One of the heaviest gases under normal
pressure
Escapes to atmosphere or into buildings
In outside atmosphere is diluted to
insignificant amounts
In confined or poorly ventilated areas of
buildings it can accumulate to high levels,
especially in the low lying areas.
How does radon accumulate?
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Building is built over bedrock or
soil that contains uranium
Air pressure in home is lower
than surrounding soil
Seeps in through:
z Cracks in foundation/walls
z Windows
z Floor drains and sumps
z Anywhere there is an opening
where the building contacts
the soil
Aspirates from water (treatment,
showers, etc.)
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water treatment plants are a
concern
Why is radon a concern?
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Affects Indoor Air Quality (IAQ) worldwide
Causes an estimated 21,000 lung cancer deaths per
year in US
2nd most frequent cause of lung cancer after
cigarette smoking
8 to 15% of lung cancer is caused by radon
6th leading cause of cancer overall
A smoker who is exposed to radon has a much
higher risk of lung cancer (5-20x greater) –
synergistic effect
14% of people who die from radon-related lung
cancer have never smoked
Why is Radon a concern in
NS?
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Nova Scotia has been identified to have
higher than the national average of lung
cancer
Nova 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?
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Because it is radioactive, radon decays
Produces 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 affected
If you breathe in alpha particles, they can
damage bronchial and lung tissue, and can
lead to lung cancer.
Radon and Lung Cancer Risk
Exposure
3
Level Bq/m
Non smoker
Smoker
Additional Risk Additional Risk
200
2%
17%
400
3%
22%
800
5%
30%
How is radon testing done?
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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 values
Alpha Track Detection
Monitors
Measurement Locations in Public Buildings
Taken From the Health Canada Protocols
Preferred device locations should be:
z By an interior wall at breathing level, but at
least 50 cm from ceiling.
z Where occupants spend much of their time.
z In occupied rooms in basements or the floor
with the lowest level occupied rooms in the
building.
z 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:
z In bathrooms, closets, cupboards, sumps, crawl
spaces or nooks because relatively little time is
spent there
z Near air currents caused by heating, ventilation,
doors, windows or fans.
z Near heat, such as over radiators or in direct
sunlight
z Near electrically powered equipment or appliances
Radon guidelines
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2006 Health Canada dropped acceptable
concentration of radon from 800 to 200 Bq/m3
If >200 Bq/m3, remedial action should be taken
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response time decreases with increasing levels found
200 to 400, 2 years to fix
400 to 600, 1 year to fix
600 to 800, 6 months to fix
Radon levels should be reduced to a value as low
as practicable
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New dwellings should use techniques that minimize radon
entry and make future removal of radon easier.
Radon mitigation
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Soil Suction
Sealing cracks and
openings
Pressurization
Eliminate Radon in
water
Heat Recovery
Ventilator
Cape Breton
University
Study
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funding received from
WorksafeBC and WCB of
Nova Scotia
z 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?
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WorkSafe BC and Nova Scotia WCB
approached for funding of workplace radon in
NS
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Received funding for 200 radon alpha detectors
Contacted workplace partners
Put on education sessions for JOHSC
Put monitors in place for 3 month periods at
selected NS workplaces
Results communicated directly to participants with
advice for remediation
Radon Sampling Locations
Nova Scotia
Radon Sampling Locations
Cape Breton
NS Workplace Results
Location
Range of Results (Bq/m3)
Average Result (Bq/m3)
Sydney
17.8 – 98.7
34.6
Lingan
10.4 – 38.5
20.3
Wreck Cove
Neil’s Harbour
Cheticamp
Inverness
Port Hawkesbury
Pt. Aconi
Trenton
Lakeside
Dartmouth
St. Margaret’s Bay
Glace Bay
Louisbourg
North Sydney
Coxheath
7.9 – 18.5
10.4 – 16.8
8.9 – 21.1
8.5 – 14.1
5.4 – 19.3
17.8 – 50.9
5.3 – 15.0
6.6 – 83.1
7.6 – 48.0
42.5 – 174.4
14.4 – 94.9
12.2 – 25.2
15.9 – 61.1
64.4 – 208.0
12.2
13.8
15.9
11.8
10.6
29.5
8.3
30.0
17.7
99.1
54.1
17.3
28.4
104.5
Workplace Findings
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Some workplaces were concerned about
participating, unsure of how to deal with
results
Only one workplace had levels above 200
Bq/m3, and then with only 2 of their 10
monitors, average was acceptable
One other workplace had levels above the
150 Bq/m3 action level.
All other workplaces were acceptable
Additional CB Residential
Survey
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Monitors provided to residents
3 month survey period
Results 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
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Crack fill, positive pressure, etc.
Findings
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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’or
5 out of 20 are above action limit of 150
Bq/m3
CB Residential Results (20)
Location/Cape
Breton
Range of Results (Bq/m3)
Average Result (Bq/m3)
Sydney
12.4 – 156.8
90.6
Glace Bay
14.8 – 69.9
47.4
Howie Centre
35.2 – 528.8
221.2
Port Morien
17.7
17.7
Bras D’or
47.3 – 381.1
214.2
Big Pond
33.6 – 117.1
75.4
North Sydney
18.3
18.3
Concerns
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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?
Conclusion
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Radon is a carcinogenic, naturally occurring gas that
is ubiquitous in the environment
Seeps into buildings through cracks and other
openings when air pressure is low inside
Exposure to levels of radon over 200 Bq/m3 for an
extended period should be avoided, especially if
you’re a smoker
New and existing homes and buildings should be
tested for radon and if unacceptable levels are
found, mitigation should be commenced
Thanks
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To WCB NS
To WorksafeBC
To safety services NS for invitation to speak
To you for listening!
Questions?