Define the retardation factor Rf of a pollutant in a soil having density of $1\mathrm{.}8$ kg$/$L$,$ porosity of $0\mathrm{.}3$

and organic fraction of $0\mathrm{.}005.$ The pollutant has octanol$-$water partition coefficient of log Kow $=$

$2$

Rf $=1+(\backslash$rho b Kp$/\backslash$eta $)$