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Evolution of dissolved organic matter during abiotic oxidation of coal tar--comparison with contaminated soils under natural attenuation

Authors :
Stéphane Parant
Catherine Lorgeoux
Pierre Faure
Coralie Biache
Ogier Hanser
Marine Boulangé
Raymond Michels
David Billet
GeoRessources
Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS)
Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC)
Institut Ecologie et Environnement (INEE)
Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo)
Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
Structure et Réactivité des Systèmes Moléculaires Complexes (SRSMC)
Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
Source :
Environmental Science and Pollution Research, Environmental Science and Pollution Research, Springer Verlag, 2015, 22 (2), pp.1431-1443. ⟨10.1007/s11356-014-3465-8⟩
Publication Year :
2014

Abstract

International audience; In former coal transformation plants (coking and gas ones), the major organic contamination of soils is coal tar, mainly composed of polycyclic aromatic compounds (PACs). Air oxidation of a fresh coal tar was chosen to simulate the abiotic natural attenuation impact on PAC-contaminated soils. Water-leaching experiments were subsequently performed on fresh and oxidized coal tars to study the influence of oxidation on dissolved organic matter (DOM) quality and quantity. The characterization of the DOM was performed using a combination of molecular and spectroscopic techniques (high-performance liquid chromatography-size-exclusion chromatography (HPLC-SEC), 3D fluorescence, and gas chromatography coupled with mass spectrometry (GC-MS)) and compared with the DOM from contaminated soils sampled on the field exposed to natural attenuation for several decades. An increase in the oxygenated polycyclic aromatic compound concentrations was observed with abiotic oxidation both in the coal tar and the associated DOM. Polycyclic aromatic hydrocarbon concentrations in the leachates exceeded pure water solubility limits, suggesting that co-solvation with other soluble organic compounds occurred. Furthermore, emission excitation matrix analysis combined with synchronous fluorescence spectra interpretation and size-exclusion chromatography suggests that oxidation induced condensation reactions which were responsible for the formation of higher-molecular weight compounds and potentially mobilized by water. Thus, the current composition of the DOM in aged soils may at least partly result from (1) a depletion in lower-molecular weight compounds of the initial contamination stock and (2) an oxidative condensation leading to the formation of a higher-molecular weight fraction. Abiotic oxidation and water leaching may therefore be a significant combination contributing to the evolution of coal tar-contaminated soils under natural attenuation.

Details

ISSN :
16147499 and 09441344
Volume :
22
Issue :
2
Database :
OpenAIRE
Journal :
Environmental science and pollution research international
Accession number :
edsair.doi.dedup.....a4ab2bec2c960c1304a622ca27111023
Full Text :
https://doi.org/10.1007/s11356-014-3465-8⟩