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

Abstract

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 mu g 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 mu g 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

Challenges in Tracing the Fate and Effects of Atmospheric Polycyclic Aromatic Hydrocarbon Deposition in Vascular Plants

“…Light PAHssuch as phenanthrene and anthraceneare first bound to the root epidermis along the elongation zone, then transmitted through epidermal cells into the root cortex of Zea mais and Triticum aestivum . In Trifolium pratense and Lolium perenne roots, phenanthrene occurs primarily in its free form, suggesting accumulation in the cytoplasm and vacuoles . In contrast, Gao et al have demonstrated that PAHs taken up by arbuscular mycorrhizal roots of L. perenne partition from cell solution into organelles.…”

“…When plants are grown in PAH-contaminated soils, PAHs are mainly adsorbed on root surfaces prior to penetrating inner root tissues. ,,,− It has been demonstrated that PAHs pass through the cell wall of ryegrass arbuscular mycorrhizal roots . Light PAHssuch as phenanthrene and anthraceneare first bound to the root epidermis along the elongation zone, then transmitted through epidermal cells into the root cortex of Zea mais and Triticum aestivum .…”

Exposure Chambers for Studying the Partitioning of Atmospheric PAHs in Environmental Compartments: Validation and Calibration Using Experimental and Computational Approaches

“…Four plastic pots are placed in the EC around the intake tube (12 cm high × 8 cm diameter). The pots were filled with 300 g dry weight (DW) of agricultural soil from Maconcourt (France) (see Chiapusio et al 29 for characteristics), sieved to 2 mm, to act as simplified microsystems. Each chamber is placed on a PMMA saucer supplying water to the pots, secured by a holder that prevents PHE water contamination.…”

“…Soil samples were dried at room temperature (18 °C) under fumehood aspiration and ground with mortar and pestle. This soil drying technique did not provoke any PHE dissipation or volatilization. , Fifty grams of dry soil mixed with diatomaceous earth was put into a 100 mL extraction cell and PHE was extracted twice with an accelerated solvent extractor (ASE 100, Dionex, France) with 60 mL of cyclohexane for 5 min at 100 °C and 100 bar.…”

“…This work’s objective was to develop a small-scale EC to study transfer and biological effects of atmospheric PAH pollution in microcosms, and to validate it by a dual approach combining experimentation and CFD simulation. Phenanthrene (PHE), a three-ring PAH predominantly in the gas phase at experiment temperature, was selected as the model PAH because of its environmental ubiquity and preponderance in air across sampling sites, , its sublimation capacity (molecular weight: 178.2 g mol –1 ; saturation vapor pressure: 0.02 Pa at 25 °C), and its frequent use in controlled conditions, e.g., in spiked soils or Petri dish growth mediums. − The approach included (1) the assessment of atmospheric PHE concentrations and dynamics in the EC, (2) PAS calibration for monitoring exposure levels, and (3) the exposure of simple microsystems (soil only) to verify the device’s effectiveness in contaminating environmental matrices. Atmospheric concentrations of PHE were expected to be homogeneously distributed within the EC, stable over time, and close to those found in situ .…”