Webinar Purpose Radon in High Water Use Facilities • To introduce people to the potential hazards Webinar of radon gas, in facilities which utilize a high volume of water 2 June 21, 2017 In this Webinar... Radon • What radon is • Radon is an odourless, colourless radioactive • Potential health hazards gas that is formed naturally by the breakdown of uranium in soil, rock and water • How radon gets into our workplace air – Alpha emitter • How to measure radon levels – Half life of 3.8 days Radon • Radon radiation protection guidelines and – Inert gas (non-reactive) regulations for radon – Water soluble Atomic Number: 86 • Measures to reduce radon exposure Atomic Mass: 222 – Somewhat more dense than air – Accumulates in enclosed spaces 3 4 Radon Progeny Radon-222 and Short-Lived Progeny • Radon progeny are the radioactive daughters Radon Gas Radon-222 Radon-222 of radon gas Polonium-218 Polonium-218 – For health-effects, only the short-lived progeny are considered Lead-214 Lead-214 Radon Daughters – Are solids or Radon Progeny – Attach to dust particles in the environment Bismith-214 Bismith-214 – When inhaled, tend to remain in the lungs Polonium-214 Polonium-214 – Two high-energy alpha emitters Lead-210 5 6 1
Radiation Dose Radon – Health Effects • Radon Progeny attach to dust particles in the air • The effects of radiation depend on the • When we breath in air, these radioactive aerosols amount of energy the radiation transfers to enter into our lungs your body. • As these decay in the lung, they emit alpha radiation which transfers • This transfer of energy to the cells energy results in a • This radiation can damage lung cells radiation dose. – No immediate symptoms – Mutations are possible • This cell damage leads to an increased risk of developing lung cancer 7 8 Radon – Health Effects Radon – Health Effects • Development of lung cancer due to radon • The risk of getting lung cancer from radon exposure is probabilistic depends on: – Not everyone exposed to elevated levels of radon – How much radon is in your workplace and home will develop lung cancer – The occupancy time in these areas – There is no lower threshold below which the – Whether you are a smoker or have ever smoked exposure presents no risk • The more dose received due to radon exposure, the higher the risk of developing lung cancer 9 10 Radon Measurement Units Radon Sources – Building Entry • How does radon enter a building? • Radon gas is measured as an activity concentration (Bq/m 3 ) – Entry where building is in contact with soil – To calculate dose, must know/assume the • Cracks in the slab/walls in contact with soil relative amounts of radon gas and its progeny • Gaps at floor-wall joints – Canadian NORM Guidelines: Exposure to • Open sump pits 200 Bq/m 3 for 2000 hours results in 1.4 mSv • Openings around utility penetrations of Effective Dose • Floor drains with no traps • Radon progeny is traditionally measured • Etc. in Working Levels (WL) – Emission from water – Being exposed to 1 WL for 170 hours results • Particularly ground/well water in 1 WLM exposure, equivalent to 5 mSv of Effective Dose – Through natural gas 11 2
Radon Sources – Water Emission Radon Sources – Water Emission • Radon in water • Facilities that use large amounts of ground water may have significantly higher radon – Radon can dissolve in water which passes through concentrations a radon source (rocks and soil with some uranium) – Radon escapes from the water into the air – Fish culture, water treatment facilities, etc. • More radon escapes from water into air when the water is agitated in air (e.g., splashing, spraying, etc.) • How easily radon transfers to air depends on the temperature of the air and water and the amount of agitation 13 14 Indoor Radon Concentration Indoor Radon Concentration • Radon concentration indoors is affected by • Radon concentration indoors is also affected by external environmental conditions – Amount of uranium in soil and building materials – Soil characteristics – Temperature – Barometric pressure – Radon concentration in water – Precipitation – Amount of water used – Heating, ventilation and air conditioning – Humidity – Wind speed – Occupancy patterns (doors/windows open or closed) How to Detect Radon How to Detect Radon • Radon progeny • Radon gas can be measured in many ways – Causes the most dose – Short term (not recommended) – Due to the very short half lives, can be • Grab Sample complicated to measure • Charcoal Canister • Radon gas – Long term (recommended) – Generally radon gas concentration is measured • Electret Monitor (E-PERM) – Radon gas is much easier to detect • Alpha Track Monitor – To convert to dose, an assumption is made about – Continuous (a good option but can be expensive) the relative amounts of radon progeny and radon • Electronic Monitor gas (the equilibrium factor) – NOTE: Must be calibrated regularly 17 18 3
How to Detect Radon Regulation of Radon in Workplaces • Federal • Long term (electret or alpha track monitors) – Federally regulated workplaces – 3 to 12 months in duration – Workplaces regulated under the Nuclear Safety and – Don’t usually require power Control Act – Sent away for analysis at the laboratory • Uranium mines, nuclear power, radiation sources, etc. • Radiation protection regulations require dose from radon to – Much better indication of long-term average be monitored and reported concentration • Provincial – Relatively inexpensive – Workplaces under provincial regulation – Recommended by Health Canada – Occupational Health and Safety Regulations – Mine Safety Regulations 19 20 Ontario Regulations Canadian NORM Guidelines • Ontario’s Occupational Health and Safety Act • Recommends all workplaces be assessed for – Employer has a duty to protect the health and safety radon concentration since it can “vary of the employee significantly” • “Take every precaution reasonable in the circumstances for • Provides occupational dose limits for exposure to the protection of a worker” – Regulation is not explicit on how to do so for radon or radon in workplaces that are not uranium mines other naturally occurring radioactive materials (federally regulated) based on worker type – Ontario Ministry of Labour staff have indicated that – Occupationally Exposed Workers, Incidentally Exposed they expect employers to follow the safety measures Workers, Members of the Public documented in Health Canada’s Canadian Guidelines – Limits are consistent with ICRP recommendations for the Management of Naturally Occurring Radioactive Material (NORM) (and Canadian federal regulation limits) 21 22 Canadian NORM Guidelines Canadian NORM Guidelines Exposure Annual Dose NORM Classification • Provides dose conversion factors based on < 200 Bq/m 3 1.4 mSv Unrestricted (0.25 WLM) measured radon or radon progeny concentration 200 Bq/m 3 – 1.4 – 5 mSv Norm Management 800Bq/m 3 -Application of an ALARA program which may • Provides classifications based on radon (0.25–1 WLM) include changes in work practices, changes to work procedures, and introduction of access concentration controls for members of the public and incidentally exposed workers – Indicates actions to be taken to protect the -Should reduce radon levels to below 200 Bq/m 3 . workers > 800Bq/m 3 > 5 mSv Radiation Protection Management (1 WLM) -A Radiation Protection Management should be implemented (radiation protection program, dosimetry for workers, provide protective equipment). -The program should include steps to reduce the radon levels to below 200 Bq/m 3 . 23 24 4
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