Personal Radiation Dose IONIZING AND NON-IONIZING RADIATION Non-ionizing: Carries LESS energy Can only excite the water molecule. Ionizing: Carries MORE energy than 1216 kJ/mol Can remove an electron from a water molecule

Strips an electron from a molecule Molecule becomes positively charged. Can cause the formation of free radicals

Contain an unpaired valence-shell electron and are extremely reactive. Destroy biologically active molecules Either remove electrons or removing hydrogen atoms from them. Damage the membrane, nucleus, chromosomes, or mitochondria of the cell; this inhibits cell division results in cell death produces a malignant cell.

Alpha Nuclei of Helium Charge = +2 Stopped by a piece of paper Beta Beta- (electron emission) Beta + (positron emission or electron capture) Positron They cause most damage when they are emitted inside the human body.

Less ionizing Damage includes burns and cancer through mutations

Dangerous in direct exposure (degree of danger is a subject of debate) Animals (including humans) can also be exposed to ionizing radiation internally if radioactive isotopes are present in the environment, they may be taken into the body. Example: radioactive iodine is treated as normal iodine by the body and used by the thyroid its accumulation there often leads to thyroid cancer.

Principal Effect of low doses: to induce cancers which don’t manifest for 20 years Principal Effect of high doses: More immediate effects Cells that are actively dividing are more susceptible to radiation exposure Bone marrow & skin more likely to sustain injury than the central nervous system or the kidneys.

Has enough energy to make the atoms in a molecule vibrate, but not remove electrons Large ranges: UV, visible light, infrared, microwaves, radio waves, and other low frequency waves. Thought to be essentially harmless below the frequencies that cause heating.

At low-energy end of the electromagnetic spectrum: (radio waves and microwaves) Excites the movement of atoms and molecules, which is equivalent to heating the sample. In or near the visible portion of the spectrum: Excites electrons into higher-energy orbitals. When the electron eventually falls back to a lower-energy state, excess energy is given off to neighboring molecules in the form of heat. Principal effect of non-ionizing radiation = increase in the temperature of the system.

Non-Ionizing: 7 moles of photons of visible light Ionizing: 300 joules of x-ray or gamma-ray radiation lethal Even though it only raises the temperature of the body 0.001°C! Internally, alpha particle radiation is even more dangerous; a dose equivalent to only 15 joules is fatal for the average human; 7 x moles of the particles emitted by alpha particles of 238 U is fatal. Polonium-210 (alpha emitter) suspected in lung, bladder cancer related to tobacco smoking!

Kill cancerous cells Generate electricity Problem: waste produces ionizing radiation Radiography—enhancing images that are hard to capture, such as inside the body. Irradiating food Medical sterilization Sterile insect technique