Implementing standardized desorption extraction into bioavailability-oriented bioremediation of PAH-polluted soils

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We applied a standardized desorption extraction method (Tenax extraction), to assess the bioavailability of native polycyclic aromatic hydrocarbons (PAHs) present in contaminated soils. Single-time point Tenax extraction at 20 h has been recently proposed by the International Organization for Standardization as one of the chemical methods to measure environmental bioavailability of nonionic pollutants (ISO/TS 16751). This work is one of the first ones that use this ISO method systematically in the field of bioremediation, and shows its advantages when used in combination with total concentrations determined with conventional, exhaustive solvent extraction. This method has been applied to different PAHs contaminated soils which had a different level of total PAHs (66-4370 mg kg(-1)) and which were from different contaminated sites and dissimilar bioremediation approaches. Inmost samples the study was focused on phenanthrene and benzo(a)pyrene as representative pollutants, although the profile of total PAHs was also studied in some samples. The results from this study show that the pollutant fractions extracted with Tenax during 20 h (D20) decreased after traditional bioremediation (biostimulation and phytoremediation), but they often increased in bioavailability-oriented treatments involving either biosurfactants or bioaugmentation with specialized microbial inocula. Therefore, D20-based assessments provided information on the bioremediation performance, not directly evident through the measurement of total PAH concentrations. (C) 2019 Elsevier B.V. All rights reserved.

We thank the Spanish Ministry of Economy, Industry and Competitiveness (CGL2016-77497-R), the Andalusian Government (RNM 2337) and the European Commission (LIFE15 ENV/IT/000396) for supporting this work. We also thank to Ilaria Re (Consorzio Italbiotec), from the LIFE BIOREST project, for the provision of the soil samples from Italy and France used in thiswork, to Fabrizio Beltrametti (Actygea SRL), for the inoculated consortia used in bioaugmentation experiments, as well as to M. Grifoll from University of Barcelona, for the provision of samples 1 and 2 from the creosote polluted site.

Peer reviewed