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Published Pressurized liquid extraction of polycyclic aromatic hydrocarbons from contaminated soils
Umeå University, Faculty of Science and Technology, Chemistry.
2000 In: Journal of Chromatography A, ISSN 0021-9673, Vol. 883, no 1-2, 151-162 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2000. Vol. 883, no 1-2, 151-162 p.
URN: urn:nbn:se:umu:diva-4629OAI: diva2:143814
Available from: 2003-05-24 Created: 2003-05-24Bibliographically approved
In thesis
1. Analysis of PAHs and their transformations products in contaminated soil and remedial processes
Open this publication in new window or tab >>Analysis of PAHs and their transformations products in contaminated soil and remedial processes
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Soil that is heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) is often found at the sites of former gasworks and wood-impregnation plants. Since PAHs are toxic these sites represent a hazard to human health and the environment, and therefore they need to be treated, preferably by a method that destroys the contaminants, and thus eliminates the problem permanently. However, during biological and chemical degradation of PAHs other toxic compounds may be formed. If these transformation products are sufficiently persistent they could potentially accumulate during remedial processes.

In the work underlying this thesis the degradation and transformation of PAHs were studied in three remedial processes: viz. a pilot-scale bioslurry reactor, microcosms with wood-rotting fungi and lab-scale treatments with Fenton's reagent. A group of transformation products referred to as oxygenated-PAHs (oxy-PAHs) was found to be particularly important, as these compounds are toxic and were shown to be relatively persistent in the environment. The oxy- PAHs were, for instance, found at significant concentrations in the gasworks soil used in most of the studies. This soil was highly weathered and had therefore been depleted of the more readily degradable compounds. In addition, experiments in which earthworms were exposed to the gasworks soil showed that the oxy-PAHs were more easily taken up in living organisms than PAHs.

To facilitate the studies, new extraction and fractionation methods were developed. For instance, pressurized liquid extraction (PLE) was investigated for its reliability and efficiency to extract PAHs and oxy-PAHs from soil. Furthermore, a selective PLE-method was developed that can simultaneously extract and separate the PAHs and oxy-PAHs into two different fractions. This was accomplished by adding a chromatographic material (silica or Florisil) to the extraction cell.

Under certain conditions all three remedial processes resulted in increasing amounts of oxy- PAHs in the soil. For example, 1-acenaphthenone and 4-oxapyrene-5-one accumulated in the bioslurry reactor. Similarly, in the soil inoculated with a white-rot fungus 9-fluorenone, benzo[a]anthracene-7,12-dione, 4-hydroxy-9-fluorenone and 4-oxapyrene-5-one accumulated. Finally, in an ethanol-Fenton treatment the concentration of some PAH-quinones increased in the soil.

The results show that it might be necessary to monitor oxy-PAHs as well as PAHs during the remediation of PAH-contaminated sites. Otherwise, the soil may be considered detoxified too early in the process. In the long term it would be desirable to include analyses with sufficient marker compounds to follow the possible production and elimination of the oxy-PAHs. However, until such compounds can be identified it is suggested that contaminated soil should be screened for oxy-PAHs in general. The selective PLE-method presented in this thesis could be a useful tool for this.

Place, publisher, year, edition, pages
Umeå: Kemi, 2003. 43 p.
Environmental chemistry, polycyclic aromatic hydrocarbons, PAHs, degredation, transformation, formation, accumulation, oxidation products, metabolites, oxogenated polycyclic aromatic hydrocarbons, oxy-PAHs, soil, gasworks, remediation, bioremediation, bioslurry, wood-rotting fungi, Fenton´s reagent, avaliability, bioavaliability, chemical analysis, extraction, pressurized liquid extraction, PLE, accelerated solvent extraction, ASE, Miljökemi
National Category
Environmental Sciences
Research subject
Analytical Chemistry
urn:nbn:se:umu:diva-57 (URN)91-7305-452-6 (ISBN)
Public defence
2003-05-24, Umeå, 10:00 (English)
Available from: 2003-05-24 Created: 2003-05-24 Last updated: 2009-12-07Bibliographically approved

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