Soil heterogeneity and surfactant desorption influence PAH distribution during electroremediation at a tar oil–contaminated site
KAUST Grant NumberKUK-C1-017-12
Permanent link to this recordhttp://hdl.handle.net/10754/668702
MetadataShow full item record
AbstractAfter a field experiment utilising electroosmosis and non-ionic surfactant Tween 80 as a remediation effort on the removal of polycyclic aromatic hydrocarbons (PAHs) from a long-term asphalt-contaminated soil, the PAH heterogeneity in the soil was yet extensive. This study come as a follow-up to address the following questions: (i) was PAH (re)distribution a consequence of the treatment? and (ii) to what extent does the surfactant affected PAH desorption and subsequent bioavailability? To answer question (i), we selected random soil samples from different locations of the field site before in situ remediation took place, and quantified and characterised soil organic matter by elemental analysis and solid-phase 13C nuclear magnetic resonance spectroscopy and PAH concentrations. Finally, batch desorption experiments with selected contaminated soil samples were carried out with and without 1% Tween 80 in the solution phase to address question (ii). Data shows that PAH concentrations were related neither to organic matter content nor to a high aromaticity of the organic matter, which serves as a proxy for the presence of tar oil. Soil heterogeneity is likely to be the cause of PAH heterogeneous distribution, but it is inferred that remediation causes weathering of the tar oil phase, resulting in the release and subsequent transport and sorption of PAH to inherent organic material. The results of the batch desorption experiments demonstrate PAH desorption up to 146 times when surfactant is present. However, Tween 80 does not enable biodegradation, since desorbed PAH molecules are entrapped inside surfactant micelles.
CitationHeister, K., & Lima, A. T. (2019). Soil heterogeneity and surfactant desorption influence PAH distribution during electroremediation at a tar oil–contaminated site. Environmental Monitoring and Assessment, 191(10). doi:10.1007/s10661-019-7776-6
SponsorsWe are grateful to Bärbel Deischl and Uta Lindstedt (Technische Universität München) for the PAH analysis and conduction of the desorption experiment, respectively. In addition, we thank Frank Volkering (Tauw B.V.) for providing the sample material and information about the field site.
This study was financially supported by the King Abdullah University of Science and Technology (KAUST) in the framework of the SOWACOR Centre in Development at Utrecht University (grant no. KUK-C1-017-12).