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Nonexhaustive cyclodextrin-based extraction technique for the evaluation of PAH bioavailability.

Reid, Brian J. and Stokes, Joanna D. and Jones, Kevin C. and Semple, Kirk T. (2000) Nonexhaustive cyclodextrin-based extraction technique for the evaluation of PAH bioavailability. Environmental Science & Technology, 34 (15). pp. 3174-3179. ISSN 0013-936X

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Abstract

Traditionally, soil extraction techniques have been concerned with the determination of ``total'' organic contaminant concentrations, following an ``exhaustive'' extraction. However, in light of the increasing body of knowledge relating to organic contaminant availability and aging, such methods have little relevance to the amount of contaminant that may pose an ecological risk i.e., the ``bioavailable'' portion. Less exhaustive techniques have therefore been the subject of more recent approaches in the hope that they may access the ``labile'' or bioavailable pool. The use of an aqueous-based extraction technique utilizing hydroxypropyl-beta-cyclodextrin (HPCD) is presented here for the extraction of PAHs from soil. The optimization of the method is described in terms of HPCD concentration, extraction time, and solution buffering. The procedure is then tested and validated for a range of C-14-labeled PAHs (phenanthrene, pyrene, and benzo[a]pyrene) added at a range of concentrations to a range of soil types. The amounts of soil-associated phenanthrene mineralized by catabolically active microorganisms were correlated with total residual phenanthrene concentrations (r(2) = 0.889; slope of best fit line = 0.763; intercept = -5.662; n = 24), dichloromethane (DCM)-extractable phenanthrene concentrations (r2 = 0.986; slope of best fit line = 0.648; intercept = 0.340; n = 24), butan-1-ol (BuOH)-extractable phenanthrene concentrations (r(2) = 0.957; slope of best fit line = 0.614; intercept = 0.544; n = 24), and HPCD-extractable phenanthrene concentrations (r(2) = 0.964; slope of best fit line = 0.997; intercept = 0.162; n = 24). Th us, in this study, the microbially bioavailable concentrations of soil-associated phenanthrene were best predicted using the optimized HPCD extraction technique. In contrast, the DCM Soxhlet extraction and the BuOH shake extraction both overestimated phenanthrene bioavailability by, on average, >60%.}

Item Type: Article
Journal or Publication Title: Environmental Science & Technology
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 18584
Deposited By: Prof Kirk T. Semple
Deposited On: 24 Oct 2008 17:51
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:19
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/18584

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