Design - Module Specifications
Constituent : con - Environmental Decay Half Times
Four environmental half times can be specified in the database, each for describing losses from specific media: groundwater, surface water, soil, and air. The environmental half time represents the time for the amount of a pollutant to be reduced by one half in the specific medium. Various processes may be responsible for the loss, depending on the chemical and medium. Values for environmental half time in the database are generally set to a large default value (9 x 10^9 days) when pollutant specific information is not available in the literature. For the medium soil, loss rate constants for volatile chemicals have been estimated using a volatilization model for old spills to provide a conservative (slow release) estimate of volatilization losses. A similar analysis has been made to estimate the environmental half time for volatile chemicals in surface waters. Environmental half times for groundwater and air are generally set to the default maximum value representing no losses. All values for radionuclides are set to the radiological half-life for the radionuclide.
Constituent Database Links
Constituent : conPhysical Parameters
Dose Factors
Environmental Decay Half Times
Environmental Transport Factors
Toxicity Factors
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