Phenanthrene Sorption and Leaching Dynamics in Two Agricultural Soils.
Samira Amellal, Arnaud Boivin, Michel Schiavon, and Corinne Perrin Ganier. Laboratoire Sols et Environnement, ENSAIA-INRA/INPL, 2 Avenue de la Forêt de Haye, BP 172, Vandoeuvre-lès-Nancy, 54505, France
The fate of phenanthrene in the subsurface of soils is affected by a complex time-dependent interplay between sorption and leaching processes. In order to assess the dynamic interactions between sorption and leaching, experiments were carried out using two different soils (clay and sandy loam) and different contact times. When phenanthrene was applied to in weak concentrations, its adsorption and desorption were similar in the two soils. The soils' physical properties appeared to be the key factor limiting phenanthrene leaching. In clay soil and sandy loam soil, after 6 months under natural climatic conditions, the amount of 14C phenanthrene leached was less than 2 % of the amount applied. The soil which exhibited the lowest leaching values was also the soil which had the strongest Kf and the lowest infiltration rate. A large quantity of residues remained extractable up to 30 days without influencing the concentrations in the leachate. However, phenanthrene was also present in a non-available state (> 27 % of bound residues) in both soils at 180 days. The mechanism of dynamic leaching of phenanthrene is still not well understood. In the future, it would be interesting to identify the transfer dynamics of this compound into soil aggregates during leaching.