Microbial degradation of xenobiotic compounds in soil columns

Aerated soil columns were tested with respect to their suitability for the enrichment of bacterial strains with specific capabilities of degrading xenobiotic compounds and for studying microbial degradation processes in soil. Investigations were performed on degradation of phenoxyalkanoic acid herbicides and chlorinated anilines. Complete degradation of 0.1 g l super(-1) 2,4-dichlorophenoxyalkanoic acids was reached within 1 week of incubation. Duration of lag phases preceding degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was dependent on substrate concentration. Lag periods prior to degradation of relatively highly concentrated solutions of 2,4-D (1.0 g l super(-1)) were significantly shortened by preincubation with lower concentrations of 2,4-D (0.02 g l super(-1)). Complete degradation of 0.2 g l super(-1) 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was obtained after 130 days of incubation.