HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Park, J.-H. Articles by Voice, T. C. Search for Related Content PubMed PubMed Citation Articles by Park, J.-H. Articles by Voice, T. C. GeoRef GeoRef Citation Agricola Articles by Park, J.-H. Articles by Voice, T. C. Related Collections Soil Kinetics Organic Compounds Agricultural Pesticides Soil Biology

TECHNICAL REPORT
Bioremediation and Biodegradation

Kinetic Modeling of Bioavailability for Sorbed-Phase 2,4-Dichlorophenoxyacetic Acid

^a Dep. of Civil and Environ. Eng., Michigan State Univ., East Lansing, MI 48824
^b Dep. of Crop and Soil Science, Michigan State Univ., East Lansing, MI 48824

* Corresponding author (voice{at}msu.edu)

Received for publication September 22, 2000. The degradation rate of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in silica–slurry systems to evaluate the bioavailability of sorbed-phase contaminant. After the silica particles were saturated with 2,4-D, the system was inoculated with the 2,4-D–degrading microorganism Flavorbacterium sp. strain FB4. The disappearance rate of 2,4-D was found to be greater than the rate predicted based upon liquid-phase 2,4-D concentrations. A kinetic formulation, termed the enhanced bioavailability model, was developed to describe the desorption and biodegradation processes in this batch system. The approach assumes that 2,4-D resides in both the liquid and solid phases and degradation occurs via both suspended and attached biomass. All biomass can degrade liquid-phase 2,4-D at one rate, while only attached biomass can degrade sorbed 2,4-D at another rate. An enhanced transformation factor (E_f) was introduced to express the increased biodegradation rate over that expected from the liquid phase only. This approach was able to account for the increased degradation rates observed experimentally. The results provide evidence that desorption to the bulk solution is not prerequisite to degradation, and that sorbed substrate may be available for degradation.

Abbreviations: MSM, minimal salts media • PBS, phosphate buffered saline • 2,4-D, 2,4-dichlorophenoxyacetic acid • FB4, Flavobacterium sp. FB4 • EDTA, ethylenediaminetetraacetic acid • EB, enhanced bioavailability