Reductive transformations of halogenated aromatics in anaerobic estuarine sediment: kinetics, products and pathways

The transformation of different classes of halogenated aromatic compounds in sulfidogenic sediment slurries was examined in laboratory incubation experiments. The results indicated that several processes were shown to occur, leading to the formation of a number of intermediate metabolites. The kinetics of transformation followed a first-order reaction mechanism, with k values in the range of 1.67 and 0.0005 day−1 or half-lives of 0.4 and 1386 days. The order of transformation rates among different classes of compounds was: phenols > anilines > benzenes > pesticides. The pathway of transformation among single-ring aromatic compounds indicated that ortho and para halogen removal was the predominant compared to meta halogen removal.