| Abstract
| - The retention of phenol, o-cresol, 2,4-dichlorophenol (DCP), and their peroxidase-catalyzed polymerization products was evaluated on two surface soils. The extractability of the parent solutes andtheir polymerization products was also investigated. 14C-Labeled radioisotopes were used to quantifythe contaminant retained on soil as water-extractable, methanol-extractable, humic/fulvic (HA/FA)acid-bound, and soil/humin bound. Between 2 and 20% of the solute retained on soil after a 7-daycontact period remained bound to the HA/FA and soil/humin components in unamended soils; in thepresence of peroxidase this amount was as high as 40−75%. The alkali-extractable HA/FA componentcontained the largest fraction of radioactivity in peroxidase-amended soils. Whereas the soil organicmatter content was the predominant factor controlling the extent of sorption of the parent phenols,the clay content and particle surface area appeared to contribute to the retention of the polymerizationproducts. High molecular weight oligomers produced during peroxidase-mediated polymerization ofphenols associate strongly with soil components and are likely incorporated into the soil organicmatter via oxidative coupling reactions. Keywords: Soil organic matter; enzyme; oxidative coupling; polymerization; humification
|
