Pentachlorophenol (PCP) is a widely used wood-treating chemical that i
s applied to wood under pressure in the form of concentrated solution
in solvents that are nonaqueous phase liquids (NAPL). As a result, any
spill at a wood-treating site using PCP results in soil contamination
with PCP in the presence of a NAPL. Hence, a study of migration of PC
P was conducted in presence of kerosene as a NAPL in unsaturated soils
. Addition of kerosene to soil caused a change in the effective size o
f soil particles; the porosity, pore velocity, and dispersion coeffici
ents, all changed (as measured by bromide breakthrough) in soil column
s contaminated with kerosene. Moisture content of soil was found to be
a key parameter determining the residual NAPL content in the soils. P
CP/kerosene breakthrough experiments showed that the organic phase pen
etrated deeper and faster into soils with higher moisture content, and
the residual kerosene acted as a sorptive phase that retarded the mig
ration of PCP.