Bioavailability of 2,4-dichlorophenol associated with soil water-soluble humic material

Shaw, Liz J. and Beaton, Yvonne and Glover, L. Anne and Killham, Kenneth and Osborn, Daniel and Meharg, Andrew A. (2000) Bioavailability of 2,4-dichlorophenol associated with soil water-soluble humic material. Environmental Science and Technology, 34 (22). pp. 4721-4726. ISSN 0013-936X. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Interaction of organic xenobiotics with soil water-soluble humic material (WSHM) may influence their environmental fate and bioavailability. We utilized bacterial assays (lux-based toxicity and mineralization by Burkholderia sp. RASC) to assess temporal changes in the bioavailability of [C-14]-2,4-dichlorophenol (2,4-DCP) in soil water extracts (29.5 pg mL(-1) 2,4-DCP; 840.2 mug mL(-1) organic carbon). HPLC determined and bioavailable concentrations were compared. Gel permeation chromatography (GPC) was used to confirm the association of a fraction (>50%) of [C-14]-2,4-DCP with WSHM. Subtle differences in pa ra meters describing 2,4-DCP mineralization curves were recorded for different soil-2,4-DCP contact times. Problems regarding the interpretation of mineralization data when assessing the bioavailability of toxic compounds are discussed. The lux-bioassay revealed a time-dependent reduction in 2,4-DCP bioavailability: after 7 d, less than 20% was bioavailable, However, GPC showed no quantitative difference in the amount of WSHM-associated 2,4-DCP over this time. These data suggest qualitative changes in the nature of the 2,4-DCP-WSHM association and that associated 2,4-DCP may exert a toxic effect. Although GPC distinguished between free- and WSHM-associated 2,4-DCP, it did not resolve the temporal shift in bioavailability revealed by the lux biosensor. These results stress that assessment of risk posed by chemicals must be considered using appropriate biological assays.

Item Type: Article
Subjects: Q Science
T Technology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: A. Xie
Date Deposited: 24 Jun 2009 10:14
Last Modified: 23 Apr 2014 13:52
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