occupational exposures to radiation

Question 1

what are the 2 major types of radiation?

Answer 1

ionizing
-sufficient energy to eject electrons from atomic nuclei-these can damage DNA (mutagenic)
-removing an electron (negative charge) creates a positively charged ion

non-ionizing
-insufficient energy to eject electrons, but can create heat (vibration)

Question 2

what are the types of ionizing radiation?

Answer 2

substances that emit ionizing radiation are termed radioactive
-alpha
-beta
-gamma
-x-ray
-neutrons
the different types of radiation vary in natural and other sources, energy, frequency and ability to penetrate material and tissue

Question 3

what are gray?

Answer 3

international unit of absorbed dose from ionizing

Question 4

what are sievert (Sv)?

Answer 4

international unit of “absorbed dose equivalent”
-dose in Gy multiplied by a “radiation weighting factors”
-this is because some types of ionizing radiation are more harmful than others (carry more energy)
-example: alpha radiation carries much more energy than x-rays (weighing factor of 20)
-one Gy of alpha radiation delivers a dose equivalent of 20 Sv (1x20) compared to 1 Gy of x-rays which deliver a dose equivalent of 1Sv (x-ray weighing factor=1)

Question 5

what is background radiation?

Answer 5

-the body can tolerate a certain amount of exposure to ionizing radiation without impairment of overall function
-naturally occurring “background radiation” (cosmic radiation, radon) results in low-level continuous exposure of around 3.6 mSv/yr
-radon is responsible for 55% of the background dose of radiation (2mSv/yr)

Question 6

what are percentages of background radiation?

Answer 6

Question 7

what are the acute health effects (acute radiation syndrome)?

Answer 7

-from brief, very high exposures
-usually 1 Gy or more
-hemopoietic syndrome (bone marrow depression, drop in white blood cells)
-gastrointestinal syndrome (10 Gy): nauseas, vomiting, diarrhea (rapid onset)
-central nervous syndrome (50Gy): vomiting, diarrhea, fluid loss, coma, death

Question 8

what are the long term effects?

Answer 8

-cancer, genetic damage
-terotogenic
-reproductive abnormalities
-organ damage, scarring

Question 9

what are some sources of exposure?

Answer 9

-Naturally occurring (ie, cosmic rays, radionuclides in body, terrestrial gamma rays, radon)
-nuclear facilities; accidents
-nuclear bombs
-medical procedures: x-rays, nuclear medicine, radiation therapy for cancer
-occupational (jobs)

Question 10

what are some occupations that have radiation?

Answer 10

-radiation workers
-mining
-medical/dental/veterinary workers
-industrial radiography
-nuclear power plant workers
-pilots, flight crew, astronauts

Question 11

what is the characteristics of workers by province/territory?

Answer 11

Question 12

what is the mean effective dose of canada?

Answer 12

Question 13

what is the collective dose of all industry of canada?

Answer 13

Question 14

what is in saskatchewan?

Answer 14

-in SK, the occupation with the most number of badged workers is radiological technologists
-in SK,if you receive less than 1 mSv per year there is no requirement to monitor workers
-however, there are more dental intra-oral units than any other type of ionizing radiation equipment in SK, so that occupational group also very common but may fall below 1 mSv per year therefore not badged consistently

Question 15

what is Saskatchewan’s uranium production?

Answer 15

-Canada is a leading producer of uranium worldwide (all from SK)
-22% of the world’s uranium comes from canada
-approx 85% of the uranium shipped from SK mines goes to non-canadian markets for the generation of electricity
-canada’s uranium exclusively used for production of electricity; strictly reinforced by international agreements and export restrictions

Question 16

what is SK uranium production regulated by?

Answer 16

closely regulated by the Canadian Nuclear Safety Commission (CNSC)
-CNSC manages certification, licensing, and compliance in accordance with the nuclear safety control act
-non-nuclear related mine activity regulated by the provincial ministry of labour (OHS)

Question 17

what is the hierarchy of controls? (protection from occupational hazards)

Answer 17

1. substitute one hazardous agent with a non-hazardous or less hazardous one, or eliminate hazard all together
2. engineering controls (enclosures, pipes, soundproofing, ventilation, etc)
3. administrative controls (rotate workers, shift scheduling, minimize exposure times, etc)
4. personal protective equipment (last line of defense)

Question 18

what are substitution examples?

Answer 18

-substituting an organic solvent like turpentine with a water based solvent which has lower toxicity
-historical examples: substituting lead based paints with lead free, or asbestos insulation with non-asbestos insulation
-get rid of the harmful material, use something none harmful (or less)

Question 19

what are engineering controls?

Answer 19

-remove the hazard from the worker or the worker from the hazard by engineering design or by isolating and/or ventilating
-isolation
-ventilation: general and/or local
-remote control vehicles to collect and deliver uranium ore
-high ventilation rates in mines to keep exposure levels low

Question 20

what are administrative controls?

Answer 20

Question 21

what is personal protective equipment?

Answer 21

-skin: gloves, sleeves, coveralls, etc
-eye/face protection
-respiratory: masks
-hearing: plugs, muffs
-radiaiton: gloves, gowns, thyroid, eyes

Question 22

what is radon?

Answer 22

-natural decay product of uranium 238
-present in soil/rocks, odourless, clourless, tasteless
-exposure occurs in basements, tunnels, etc due to proximity withs soil
-#2 cause of lung cancer in canada (16%) Smoking is #1

Question 23

what are the radon exposures of canada?

Answer 23

Question 24

what is saskatchewan’s radon potential?

Answer 24

Question 25

what does health canada say about radon?

Answer 25

-recommends taking action to reduce radon levels if over 200 Bq/m3