Chapter 8 Ionizing and Non-Ionizing Radiation

exposure

"A quantity used to indicate the amount of ionization in air produced by X- or gamma-ray radiation. The unit is the roentgen (R)."

absorbed dose

"The radiation energy absorbed per unit mass of an organ or tissue and is used in studies of the damage to a particular organ or tissue."

radioactivity

"The spontaneous emission of radiation from the nucleus of an unstable atom. As a result of this emission, the radioactive atom is converted, or decays, into an atom of a different element that might or might not be radioactive."

electromagnetic frequency

Electricity that flows through transmission lines may produce electromagnetic fields (EMFs). Research literature suggests that findings are inconsistent, not definitive, with respect to EMF exposure and cancer.

examples of non ionizing radiation

Extremely low frequency (ELF) radiation (e.g., high tension power lines) AM, FM, VHF-TV radio waves Microwave radiation Infrared radiation (IRA, IRB, IRC) - the source of heat in heat lamps used for keeping food warm Visible light radiation Ultraviolet radiation (UVA, UVB, UVC)

health effects of non ionizing radiation

Extremely low frequency (ELF) radiation does not appear to produce many discernible short-term health effects. Higher frequency levels (i.e., radiofrequency and microwave radiation) causes heating of the body.

uranium

A common element in the earth's crust Uranium ores uraninite and pitchblende are found in large amounts in North America, Africa, and Australia. Nearly all plants, animals, and aquifers contain tiny amounts of uranium.

medical uses of ionizing radiation

About 40% of radiation exposure has been attributed to medical exposure. Medical procedures include the use of X-ray machines, nuclear medicine, and radiation therapy

radio frequency radiation and cell phones

Cell phones are a very low-power apparatus that transmits in the radiofrequency range of 900 to 1800 megahertz (MHz). As of 2009, there were an estimated 270 million and 4.1 billion cellular telephones in use in the U.S. and worldwide, respectively. Widespread popularity of cell phones means that even small adverse health effects could have substantial implications for population health. Cell phone antenna banks are themselves a source of RF radiation.

natural sources of exposure to ionizing radiation

Cosmic radiation (radiation from space) Uranium deposits that cause increases in background radiation levels in some geographic areas Radon A decay product of uranium, radioactive radon gas may seep into homes, thus exposing the residents.

Natural sources of ionizing radiation

Cosmic rays Other forms of radiation that impinge upon earth from outer space Radiation from geologic formations that contain radioactive elements (radioelements) such as uranium, from which radon gas is formed as a decay product

common units of radiation

Curie (Ci): A unit of measure used to describe the amount of radioactivity in a sample of material. Rad: Radiation absorbed dose. The former unit of absorbed dose of ionizing radiation.

acute health effects of ionizing radiation

Include tissue burns and radiation sickness (e.g., nausea, weakness, and loss of hair) At low levels: usually does not produce immediately detectable harm At high levels: capable of producing fatal injuries

radon

Inert, colorless, and extremely toxic gas Produced by the decay of radium and uranium Classified as a Class A carcinogen Associated with long-term adverse health effects

non ionizing radiation

Nonionizing radiation refers to "Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons, . . . Examples of this kind of radiation are sound waves, visible light, and microwaves."

nuclear facilities and accidents

Nuclear facilities include weapons production plants, test sites, and nuclear power plants. The major consequence of the Three Mile Island accident was that no new nuclear power plants have been built in the United States since 1979. One of the largest accidents was at a nuclear facility in Chernobyl, Ukraine, in 1986.

anthropogenic sources of exposure to ionizing radiation

Nuclear power plants have been known to leak ionizing radiation into the environment under unusual conditions. Radioactive fallout from above-ground nuclear testing has exposed large populations to radiation. Decommissioned and abandoned nuclear weapons facilities and storage of nuclear wastes can be a source. Medical X-rays and radiation diagnostic and therapy procedures produce exposures to ionizing radiation.

dose equivalent

Obtained by weighting the absorbed dose in an organ or tissue by a radiation weighting factor that reflects the biological effectiveness of the charged particles that produce ionization within the tissue.

sources of exposure to ELF (50 to 60 Hertz)

Originates from electric power poles, wiring in the walls of buildings, and some electrical appliances

types of ionizing radiation

Particulate energy (e.g., highly energetic protons, neutrons, and α and β particles) Electromagnetic energy in the form of photons (e.g., γ rays and X-rays)

further effects of a nuclear explosion

Persons near the nuclear explosion would experience thermal burns and radiation-induced skin injuries. A major byproduct of the detonation of a nuclear weapon is radioactive fallout. Radioactivity will dissipate over several weeks, but crops and food animals taken from the area may be unsuitable to consume.

extraterrestrial radiation

Primary cosmic rays originate from outer space (e.g., the earth's galaxy and the sun) and interact with the earth's atmosphere to produce secondary cosmic rays. Cosmic rays have the ability to penetrate and cross the human body easily.

Ionizing radiation

Radiation that "has enough energy to remove tightly bound electrons from atoms, thus creating ions."

common units of radiation, continued

Rem: (Roentgen equivalent in man) A measure of radiation dose related to biological effect. A rem is a measure of dose deposited in body tissue, averaged over the mass of the tissue of interest. Roentgen (R): The unit of exposure from X- or gamma rays

effects of UV radiation

Temporary conditions include burns and temporary blinding Long-term consequences: Photoaging of the skin Nonmelanoma skin cancer (NMSC) Malignant melanoma (MM) Retinal damage Lens opacities

effects of a nuclear explosion

The blast (damage to or destruction of buildings and those in them) Heat (destruction or injury by high temperatures or fire) Intense light (damage to eyesight) Ionizing radiation (causing Acute Radiation Syndromes of different degrees of severity)

Radiation

The term radiation refers to "Energy traveling through space. Some types of radiation associated with radioactivity are alpha and beta particles and gamma and X rays." Radiation also includes neutrons, which are uncharged.

stochastic effects

The term stochastic means that there is an increased probability of the occurrence of an adverse health event. Associated with low levels of exposure to radiation over long time periods. Carcinogenesis and genetic damage such as changes in DNA are possible stochastic effects of radiation exposure.

factors that affect the amount of radiation exposure

The total amount of time exposed to the radioactive source Distance from the radioactive source Degree of radioactivity (rate of energy emission) of a radioactive material

the ultraviolet (UV) index

To help protect exposed persons from excessive amounts of sunlight, the UV index provides a daily forecast of the expected risk of overexposure to the sun. The index predicts UV intensity levels on a scale of 1 to 11+, where low indicates a minimal risk of overexposure and 11+ means an extreme risk. The index is calculated on a next-day basis for every ZIP code across the United States.

UVR

UVR coming from the sun is subdivided into UVA, UVB, and UVC, depending upon the wavelength of the light. Of the three forms of UVR, UVB is considered to be the form that is most harmful to human health.

sources of ultraviolet radiation (UVR)

Welders' arcs Lamps used for tanning beds Some flood lamps used in photography Halogen desk lamps Lightning Electrical sparks Sunbathing

Anthropogenic (man-made) sources of ionizing radiation

X-rays and other procedures used in medicine (medical tests and therapies) Consumer products Radioactive substances used in industry Nuclear power generators Radioactivity (e.g., radioactive fallout) from the production and detonation (primarily for testing purposes) of nuclear weapons.

Ionizing radiation's properties are used to

generate electric power, to kill cancer cells, and in many manufacturing processes.