Investigating the effect of plants on PAHs dissipation and bioaccessibility in brownfield contaminated soils (3 and 6 months cultures).

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistant organic compounds of major concern that tend to accumulate in the environment, damaging ecosystems and health. Brownfields represent an important tank for PAHs and require remediation.
As an alternative to environmentally aggressive, expensive and often disruptive soil remediation strategies, experiences have been carried on to understand and develop techniques based on bioremediation and phytoremediation.
The main objective of the study was to investigate the potential of plants (Medicago sativa L. or Trifolium pratense L.) as PAHs bioremediation enhancers on an aged-contaminated soil.
The first step was to adapt a bioaccessibility measurement protocol, using Tenax® beads, to the studied contaminated soil. Meanwhile soil samples were cultured in pots with one of the plant species for three, six, nine, and twelve months and compared to unplanted soil samples. Each modality was repeated five times for a total of 60 samples.
PAHs desorption kinetics were established for 15 PAHs and described by a site distribution model. A common Tenax® beads extraction time (24 h) was established as a comparison basis for PAHs bioaccessibility assessments.
Bioaccessible and residual PAHs were quantified using High-Performance Liquid Chromatography with Fluorimetric Detection (HPLC-FLD) on the three and six months samples, as the experiment is still underway. Preliminary results will be discussed.