Kinetics of Mineralization of Phenols in Lake Water

摘要

The kinetics of mineralization of phenol and p-nitrophenol in lake water was determined at concentrations from 200 pg/ml to 5 micrograms/ml. The mineralization data were fit by nonlinear regression to equations for 14 kinetic models that describe patterns of biodegradation by nongrowing cells or by microorganisms growing on either the test chemical or other organic substrates. Under the test conditions, usually less than 10% of the phenol C that was metabolized was incorporated into microbial cells or retained by other particulate material in the water at substrate concentrations of 10 ng/ml or less, and the percentage increased at higher substrate concentrations. Removal of particles from lake water sampled after heavy runoff from land resulted in a change in kinetics of phenol mineralization. The patterns of mineralization of 0.5 ng to 1.0 microgram of p-n trophenol per ml were best fit by the Monod-with-growth model or the logistic model if it is assumed than p-nitrophenol was the carbon source for growth, or by models that assume logarithmic or logistic growth on uncharacterized organic matter in the water. Reasons for two models fitting the same data well are considered, as are bases for selecting between models.