The concentration of a substance in air, water, or soil that occurs naturally or is the result of human activities not related to a hazardous waste site; conditions in the area near, but not affected by, a hazardous waste site. "Background samples" are often taken to compare an area's natural or pre-existing conditions to conditions at a hazardous waste site.
The concentration of a hazardous substance that provides a defensible reference point with which to evaluate whether or not a release from the site has occurred. The background level should be reflective of the concentration of the hazardous substance in the medium of concern for the environmental setting on or near a site. Background level does not necessarily represent pre - release conditions, nor conditions in the absence of influence from source(s) at the site. Background level may or may not be less than the detection limit, but if it is greater than the detection limit, it should account for variability in local concentrations. Background level need not be established by chemical analysis.
Levels representing the chemical, physical, and biological conditions that would result from natural geomorphological processes such as weathering or dissolution.
1) Naturally occurring levels: ambient concentrations of chemicals present in the environment that have not been influenced by humans.
The normal concentration of a chemical in the environment.
the amplitude level of the undesired background noise
A typical or average level of a chemical in the environment. Background often indicates levels that occur naturally or uncontaminated levels.
The amount of an AGENT in a MEDIUM (e.g., water, soil) that is not attributed to the SOURCE(s) under investigation in an EXPOSURE ASSESSMENT. BACKGROUND LEVEL(s) can be naturally occurring or the result of human activities. (Note: natural background is the concentration of an AGENT in a MEDIUM that occurs naturally or is not the result of human activities).
The normal or typical level of a chemical in the environment, often referring to the naturally occurring level
Normal environmental concentration of a chemical.
In air pollution control, the concentration of air pollutants in a definite area during a fixed period of time prior to the starting up, or the stoppage, of a source of emission under control. In toxic substances monitoring, the average presence in the environment, originally referring to naturally-occurring phenomena.
An average or expected amount of a chemical in a specific environment, or amounts of chemicals that occur naturally.
A typical or average level of a chemical in the environment. Background often refers to naturally occurring or uncontaminated levels.
the average or expected amount of a substance in a specific environment.
A typical level of a chemical in the environment. Background often refers to naturally occurring or uncontaminated levels. Background levels in one region of the state may be different than those in other areas.
(3) the amount of pollutant present in water or air from natural sources.
1. The concentration of a substance in an environmental media (air, water, or soil) that occurs naturally or is not the result of human activities. 2. In exposure assessment the concentration of a substance in a defined control area, during a fixed period of time before, during, or after a data-gathering operation.
Generally, the amount of a substance that occurs naturally in the environment.
In air pollution, the level of pollutants present in ambient air from natural sources. More generally, the level of pollution present in any environmental medium attributable to natural or ubiquitous sources. [S. L. Brown
In contaminant monitoring, the average presence of a substance in the environment, originally referring to naturally occurring phenomena.
Concentration of background pollution. Compare ambient air.
