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

L. J. Shaw*, Y. Beaton, L. A. Glover, K. Killham, D. Osborn, A. A. Meharg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


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 [14C]-2,4-dichlorophenol (2,4-DCP) in soil water extracts (29.5 μg mL-1 2,4-DCP; 840.2 μg 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 [14C]-2,4-DCP with WSHM. Subtle differences in parameters 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.

Original languageEnglish
Pages (from-to)4721-4726
Number of pages6
JournalEnvironmental Science and Technology
Issue number22
Publication statusPublished - 15 Nov 2000

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

Fingerprint Dive into the research topics of 'Bioavailability of 2,4-dichlorophenol associated with soil water-soluble humic material'. Together they form a unique fingerprint.

Cite this