REDUCTIVE DECHLORINATION OF PCDD F BY ANAEROBIC CULTURES AND SEDIMENTS/

The fate of highly chlorinated (5 to 7 chlorines per molecule) dibenzo -p-dioxin (PCDD) and dibenzofuran (PCDF) congeners was studied in anae robic microcosms, using polychlorinated biphenyl (PCB)-contaminated Hu dson River sediments, and creosote-contaminated aquifer sediments. The PCDD/PCDF concentrations in active microcosms were shown to decrease at higher rates than in chemical and biological controls. The net loss of PCDD/F from active microcosms was up to 35% higher than in autocla ved controls after extended incubation periods. Lesser chlorinated PCD D/F, identified to be peri-dechlorinated, have been found as the accum ulating products resulting from reductive dechlorination under anaerob ic methanogenic conditions.