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Microbial release of 2,4-dichlorophenyl bound to humic acid or incorporated during humification

Journal Article · · Journal of Environmental Quality; (United States)
OSTI ID:5327267
; ;  [1]
  1. Pennsylvania State Univ., University Park (USA)

The microbial release of {sup 14}C-labeled 2,4-dichlorophenol (DCP) bound to synthetic and natural humic materials or polymerized by enzymes was investigated to evaluate the possibility of future adverse effects if binding or polymerization is used for decontamination purposes. After 12 wk of incubation with microorganisms obtained from a forest soil, the amounts of substances released into the media were very small (maximum 2.2% of the initially bound {sup 14}C) without regard to the kind of the polymer into which {sup 14}C-DCP was incorporated. Most of the radioactivity (46.2 to 80.8%) remained bound to the precipitated humic materials or in the DCP-polymer (90.1 to 97.0%). Certain amounts of the released substances evolved in the form of {sup 14}CO{sub 2} (1.0 to 9.4% from humic materials and 0 to 0.5% from a DCP-polymer). The rate of mineralization differed depending on the type of DCP binding - surface-bound or incorporated during synthesis of humic acid - and on the kind of polymer to which {sup 14}C-DCP was attached. The release into the media and {sup 14}CO{sub 2} evolution for synthetic and natural humic acids was essentially the same. When only DCP was present in the growth medium, the formation of {sup 14}CO{sub 2} was less than from a DCP-humic acid complex; this may indicate that {sup 14}CO{sub 2} from a DCP-humic acid complex originated mostly from DCP derivatives. The data obtained for DCP did not provide any evidence for a delayed pollution problem associated with polymerization or binding of xenobiotics to humic acids.

OSTI ID:
5327267
Journal Information:
Journal of Environmental Quality; (United States), Journal Name: Journal of Environmental Quality; (United States) Vol. 19:3; ISSN JEVQA; ISSN 0047-2425
Country of Publication:
United States
Language:
English