12 radionuclides

Question 1

what are the objectives of this lecture?

Answer 1

-to learn about characteristics of radionuclides as environmental pollutants: what is unique about them? (hazardous properties due to physical makeup, not chemical)
-to understand their source, mechanisms of action, and human and environment health consequences of radionuclide contaminations

Question 2

what is the overview of radiation?

Answer 2

-either ionizing (high energy, can ionize molecules in their path) or non-ionizing
-risks of injury from exposure to ionizing radiation (due to physical property)

Question 3

what are the sources of radioactivity?

Answer 3

natural
-cosmic rays
-natural radioisotopes

anthropogenic
-nuclear reactors (used nuclear fuels) (weapons, development, energy production)
-waste from uranium mining and milling
-production of medical radioisotopes
-x-rays

Question 4

what is the uranium mining, milling and usage sites in canada?

Answer 4

Question 5

what are the types of radioactive waste?

Answer 5

low radioactivity waste (high volume):
-contains material with limited amounts of long-lived activity
-low-level waste requires isolation and containment for up to a few hundred years

intermediate radioactivity waste (low volume):
-typically exhibits levels of penetrating radiation and contains significant quantities of long-lived radionuclides

high radioactivity waste (low volume):
-includes used nuclear fuel and other wastes (e.g. fuel reprocessing wastes) that have been declared as radioactive waste
-used nuclear fuel is associated with penetrating radiation and contains significant quantities of long-lived radionuclides
-most hazardous

Question 6

what is the radioactive waste production: globally and in canada?

Answer 6

Question 7

what is the containment of radioactive waste in canada?

Answer 7

Question 8

what are the types of ionizing radiation?

Answer 8

-alpha particles
-beta particles
-gamma rays
-X-rays
-neutron particles

Question 9

what is the table of uranium decay series?

Answer 9

Question 10

what are alpha particles?

Answer 10

-relatively large mass
-consists of two protons and two neutrons
-do not travel far: range in air is 1-2 inches
-offer minimal external hazard
-can cause significant regional cellular damage when internalized (inhaled or ingested)

Question 11

what are beta particles?

Answer 11

-electrons/positrons emitted during decay
-half the charge of alpha particles
-travel further than alpha particles
-less dangerous internally, but still can cause significant regional injury

Question 12

what are gamma rays?

Answer 12

-electromagnetic wave/ no charge
-ionize matter by direct interaction with orbital electrons
-highly penetrating
-can produce whole body exposure
-equally dangerous with external or internal exposure

Question 13

what is the nature and intensity of the decay?

Answer 13

electromagnetic photons (gamma and x-rays)
-lowest energy
-high penetrating ability

beta particles
-higher energy
-less penetrating (2-3 mm of aluminum or 2-3 cm of flesh)

alpha particles
-highest energy
-stopped by a sheet of paper or outer skin surfaces

Question 14

what are the intensity of the radioactive substance units?

Answer 14

SI unit: becquerel (Bq)
-number of atoms disintegrating per second

older units: curie (Ci)
-number of disintegrations per second in 1 g of radium
-1 Ci=3.7x10^10 Bq

Question 15

what are the “biologically meaningful” units of radioactivity?

Answer 15

take into account the nature of radioactivity
-alpha: less penetrating but most damaging due to large mass
-beta: more penetrating but less damaging
-gamma: highly penetrating, damage similar to beta

SI unit: gray (Gy)
-amount of radiation causing of 1 kg of tissue to absorb 1 joule of energy

SI unit: sievert (Sv)
-takes into account the damaging potential of the absorbed energy
-“safe” annual dose for human beings is 1 mSv

Question 16

what are the units of radiation dose/destructive potential?

Answer 16

-(dose in Gy) x QF = sievert (Sv)

QF= 1 for gamma, x-rays ad beta particles
QF= 20 for neutrons and alpha particles

Question 17

what was the poisoning with polonium-210 (an alpha emitter)?

Answer 17

russian spy (worked for KGB)
-went to UK, then got poisoned by KGB
-found almost all internal organs had melted away

Question 18

what are the effects of ionizing radiation on different taxonomic groups?

Answer 18

Question 20

what is the sensitivity of tissues and organs to radiation?

Answer 20

from most to least sensitive:
-blood-forming organs
-reproductive organs
-skin
-bone and teeth
-muscle
-nervous system

-embryos and fetus are more sensitive than adults

Question 21

what is the indirect effect and direct effect of radiation?

Answer 21

Question 22

what is the mode of toxic action of radiation?

Answer 22

Question 23

what are the physiological effects of radiation?

Answer 23

Question 24

what are the factors affecting radionuclide toxicity?

Answer 24

Question 25

what is the chernobyl case study?

Answer 25

-children and adolescent exposed have increase in thyroid cancer (iodide 131 was one of the ones released) -clean up people gave increased rates of cardiovascular, cataracts and blood cancers

Question 26

what was the research into birds around chernobyl?

Answer 26

Question 27

what was the fukushima nuclear disaster in japan?

Answer 27

radioactivity released and fall-out: -air: one-tenth of chernobyl disaster -significant amounts also released into the ground and ocean waters -contamination of I-131 and Cs-134/137 in drinking water and food, up to 200 miles from the nuclear plant -farming abandoned in 12 mile evacuation zone

Question 28

what is the graph of the fukushima-derived radionuclides in the ocean and biota off Japan?

Answer 28

Question 29

what is the summary report on fukushima accident contaminants in canada?

Answer 29

Question 30

how did they test butterflies?

Answer 30

Question 31

what were the generational effects in the butterflies?

Answer 31

Question 32

what is the case study of human heath risks associated with low level radioactive contamination in northern saskatchewan?

Answer 32

Question 33

what is the human exposure risk of northern saskatchewan?

Answer 33

Question 34

what were the effects of uranium mining and milling on benthic invertebrate communities in the athabasca basin of northern saskacthewan?

Answer 34

-the composition of some invertebrates (live in sediments) communities has changed due to exposure to uranium mining activities in northern saskatchewan -the number of benthic invertebrate taxa downstream at half of the uranium mine/mill effluent release points was lower compared to the number of taxa observed in reference conditions -taxon richness was lower in lakes in higher concentrations/activities of measured metals and radionuclides in the sediments -the general decreasing trend in taxon richness with increasing metal concentration and radionuclides activity was consistent for both reference and exposure lakes: implying a natural background influence of these contaminants -these effects are not just from radionuclide waste, but also metals -already have high radiation due to Saskatchewan's geolocation

Question 35

what is EARMP? what were the results?

Answer 35

10-year summary report -results have consistently demonstrated that water and traditional foods remain sale for consumption and that they continue to be safe and a healthy dietary choice for residents of the athabasca basin

Question 36

what is dangerous in a third of saskatchewan home?

Answer 36