Implementing standardized desorption extraction into bioavailability-oriented bioremediation of PAH-polluted soils
2019
Posada-Baquero, Rosa | Martín, María López | Ortega-Calvo, Jose Julio
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. In most 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.
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