Two biochemical forms of phenanthrene recovered in grassland plants (Lolium perenne L. and Trifolium pratense L.) grown in 3 spiked soils

摘要

Plant storage is a key component in the global cycling of persistent polycyclic aromatic hydrocarbons (PAHs) and constitutes a crucial step to understand environmental fate of such pollutants. This work aimed at quantifying biochemical forms of phenanthrene (PHE) stored in plants and determining the main parameter between the plant species and the soil characteristics involved in the PHE bioaccumulation. An experiment was conducted in a growth chamber to study the storage of PHE in ryegrass and clover in three distinct artificially contaminated soils (1,000 μg g−1 DW). A preliminary experiment was designed to develop an extraction method which distinguished easily extractable PHE (free-PHE) from less extractable PHE (bound-PHE). PHE was found to be mainly recovered in plant roots (around 90% of the total PHE recovered in plants) in its free form. PHE was transported upward from the roots into shoots. PHE recovered in shoots (around 1 μg g−1) was divided into its free (60%) and bound (40%) forms except for one treatment. Observed differences of root PHE storage were clearly related with the PHE dissipation in soil and then with the plant species. This work outlined the importance of quantifying the bound and free PAHs in plants in further researches.