Shaw, L.J. and Beaton, Y. and Glover, L.A. and Killham, K. and Osborn, D. and Meharg, A.A. (2000) Bioavailability of 2,4-dichlorophenol associated with soil water-soluble humic material. Environmental Science & Technology, 34 (22). pp. 4721-4726. ISSN 0013-936X.
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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.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||A. Xie|
|Date Deposited:||24 Jun 2009 10:14|
|Last Modified:||24 Jun 2009 10:14|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/16626 (The current URI for this page, for reference purposes)|
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