Soil – Air And Sediment – Water Partition Coefficient
The soil matrix includes the following multicomponent such as
It also includes the soil that are contaminated with free phase of organic compounds or mixture of compounds or soil – organic carbon phase. The chemical concentration in soil is relative sum of all chemical concentration existing in all phases of soil. The soil matrix concentration Csm or mass balance of soil matrix is expressed as follows
Csm = Θsp Csp + ΘW CW + ΘA CA + Θorg Corg
Csm = mass of chemical/volume of soil
Where Θsp refers to fractional volume of soil particles
ΘW refers to fractional volume of soil – water
ΘA refers to fractional volume of soil – air
Θorg refers to fractional volume of soil – organic carbon
The soil matrix – air partition coefficient is expressed as follows.
Hsm/A = Csm/ CA
The Csm value is substituted in Hsm/A to get the following equation.
Hsm/A = (1- ε) Hsp/A + ΘW HW/A + ΘA + Θorg (1/HA/org)
where ε is porosity of soil. Soil porosity is referred as fractional volume of soil total void space to fractional volume of soil solids (1- ε).
Hsp/A is ratio of solid particles to air partition coefficient (Hsp/A = Csp/CA)
HA/org is air – organic phase partition coefficient (HA/org = CA/Corg)
The sediment – water partition coefficient can be expressed in the absence of free organic phase as follows
Hsed/W = (1- ΘW) Hsp/W + ΘW
in which, Hsed/W is assumed to impose no air inside sediment.