Epicenter - doe-hdbk-1188-20060126

DOE-HDBK-1188-2006

Executive Order 12898 directs federal agencies to make achieving environmental justice part of their

missions by identifying and addressing disproportionately high and adverse effects of agency

programs, policies, and activities on minority and low-income populations. (See minority population

and low-income population.) [Derived from EPA EJ and E.O. 12898]

67. EPICENTER. The point on the earth's surface directly above the focus of an earthquake. [AGI 76]

68. EPIDEMIOLOGY. Study of the occurrence, causes, and distribution of disease or other

health-related states and events in human populations, often as related to age, sex, occupation, ethnic,

and economic status, in order to identify and alleviate health problems and promote better health.

[Derived from EPA Glossary, ATSDR GL]

69. EXPOSURE. The condition of being subject to the effects of or acquiring a dose of a potential

stressor such as a hazardous chemical agent or ionizing radiation; also, the process by which an

organism acquires a dose of a chemical such as mercury or a physical agent such as ionizing radiation.

Exposure can be quantified as the amount of the agent available at various boundaries of the organism

(e.g., skin, lungs, gut) and available for absorption.

In the radiological context "exposure" refers to the state of being irradiated by ionizing radiation or the

incidence of radiation on living or inanimate material. More specifically, radiation exposure is a

dosimetric quantity for ionizing radiation, based on the ability of radiation to produce ionization in air.

It is the time integral of the radiation intensity incident at a given position. Exposure is expressed in

units of roentgens (R) or coulombs per kilogram (C/kg).

Note: Although still encountered occasionally as a unit of exposure, the roentgen is no longer

in favor; the coulomb per kilogram is the SI unit of exposure and is now generally accepted.

[Derived from MW, 10 CFR 20.1003, Suter, ANSI N1.1, ANSI N13.6, NBS 55, ICRP]

70. EXPOSURE PATHWAY. The course a chemical or physical agent takes from the source to the

exposed organism. An exposure pathway describes a mechanism by which chemicals or physical

agents at or originating from a release site reach an individual or population. Each exposure pathway

includes a source or release from a source, an exposure route, and an exposure point. If the exposure

point differs from the source, a transport/exposure medium such as air or water is also included.

[Derived from EPA Terms]

71. FINDING OF NO SIGNIFICANT IMPACT (FONSI). A public document issued by a Federal

agency briefly presenting the reasons why an action for which the agency has prepared an

environmental assessment has no potential to have a significant effect on the human environment and,

thus, will not require preparation of an environmental impact statement. (See environmental

assessment and environmental impact statement.) [Derived from 10 CFR 1022.4(g)]

72. FISSILE MATERIAL. General definition:

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