Pyrene and lead transport in unsaturated soil at two different water saturations

ABSTRACT In the present paper, we focus on the study of the transport of mixtures of inorganic and organic compounds (Pyrene and lead) on unsaturated soil at two different water saturations. The soil used is a mixture of sand, clay, and organic matter. The transport of solutes exhibiting different sorption characteristics under steady-state conditions at 0.3 and 0.21 volumetric water contents (VWC) of the porous medium was experimentally investigated in a column. The Thomas model and the two-site first-order approach were used for modeling the adsorption/desorption steps. As the first results, the adsorption and desorption of mono- compound show a strong fixation of the lead than for the pyrene. In addition, the coexisting pollutant tests show the decrease of the lead and pyrene adsorption on soil and the decrease in lead retention after the desorption step. Tests with lower VWC show enhancement of lead adsorption with the multipollutant condition. The model approach shows that the equilibrium condition is not appropriate for all tests even for the lead adsorption.