ENSC 201 - Ionizing radiation

What are the two types of radiation (ionization)

non ionizing and ionizing

What are the types of ionizing radiation?

Particulate Radiation:

• Alpha particles: Heavy (2 protons, 2 neutrons), lose energy quickly, cannot penetrate skin but dangerous if inhaled/ingested.

• Beta particles: Small, negatively charged electrons, penetrate 1-2 cm into water or flesh.

• Neutrons: Produced in nuclear reactors, penetrate the furthest.

Electromagnetic Waves:

• Gamma rays: High-energy waves, penetrate more than alpha and beta particles.

• X-rays: Similar to gamma rays but artificially produced.

What is radioactive decay?

The process in which unstable elements decay by releasing energy. Most elements have a mix of isotopes, with only a small proportion being unstable.

What are isotopes?What are radioisotopes?

isotopes-Variants of an element that have the same number of protons but different numbers of neutrons.

radioisotopes-Unstable isotopes that release energy as they decay.

examples of natural radioactivity

• potassium

• tritium - produced by reaction of cosmic rays w/ atmospheric gases

• uranium - decay chain include radon and polonium

• polonium - emits alpha particles

What is radon?

Radon is a naturally occurring radioactive gas produced by the decay of uranium found in soil, rock, and water. It is ubiquitous on Earth.

What is the residential exposure pathway of radon?

Radon seeps from soil and rock into homes through cracks in foundations, floors, and walls. It can accumulate in basements and lower levels, posing a health risk through inhalation.

what are the residential radon levels in Canada

Radon levels in Canada vary by region, with some areas exceeding the guideline of 200 Bq/m³ set by Health Canada. Regular testing is recommended for homes, especially in high-risk zones.

what are radon and human health effects?

Radon exposure is linked to an increased risk of lung cancer, particularly among smokers. Long-term inhalation of radon can lead to significant health issues due to its radioactive decay products.

when/how was radon identified as a health problem?

noted that underground uranium miners who were exposed to radon died of lung cancer at higher rates

what are manufactured sources of radiation

• x-rays - valuable imaging tool, uses small dose of radiation

• therapeutic radiation - treatment with radiation (eg. x rays, gamma rays, charged particles) used to treat cancer

what is sievert (SV)

A unit of measurement for ionizing radiation dose, representing the biological effect of radiation on human tissue.

what is Tinea wapitis irradiation

in 1905-1960, x rays were used for treatment of ringworm of the scalp in children

200,000 children worldwide were irradiated

what are manufactured sources of radiation

nuclear weapons - Hiroshima and Nagasaki

nuclear power production

what are the environmental impact of nuclear power stations

warming of waterways which changes the surrounding ecosystem

what is the myth of environmental impact of nuclear power stations

emission of radioactive waste into the air, waterways and by fallout onto the land

what are the agricultural and environmental impacts of Chernobyl?

large areas of land in former Soviet Union are unusable

What happened at the Fukushima Daiichi nuclear power plant in 2011?

An earthquake on March 11, 2011, triggered a tsunami that disabled AC power to Units 1, 2, and 3, washing away fuel tanks for emergency diesel generators. Hydrogen explosions released radioactivity, including Iodine-131 (¹³¹I) and Cesium-137 (¹³⁷Cs).

IARC group 1

• all types of ionizing radiation

  • plutonium

  • radioiodines

  • raidium

  • radon

• uv radiation

what are the targets

genetic material and cellular structures that can lead to mutations and cancer.

genotoxic?

Referring to agents that damage genetic material, leading to mutations or cancer.