REDUCTIVE DECHLORINATION PATHWAYS OF CHLORO ORGANICS UNDER ANAEROBIC CONDITIONS

The transformation pathways of chloroanilines (CAs), chlorobenzenes (C Bs) and chlorophenols (CPs) were examined in anaerobic sediment collec ted from the Tsurumi river, Japan. The sediment was pre-exposed to var ious organic chemicals from the surrounding industries and appears to be sulfidogenic. Experiments were carried out for each compound in the sediment slurry, which was spiked at a desired concentration. The tra nsformation of the parent substrate and the appearance of its metaboli tes were monitored for a year. All the compounds transformed without a ny lag period. For CBs, the preferential Cl removal was in the order: two CI atoms on adjacent carbon atoms > one Cl atom on adjacent carbon > no adjacent Cl atom on the carbon. In case of CPs, ortho dechlorina tion was the preferred pathway, while for CAs, sequential removal of o rtho and para positions was observed. Copyright (C) 1996 IAWQ.