DECHLORINATION OF SPIKED PCBS IN LAKE SEDIMENT BY ANAEROBIC MICROBIALGRANULES

An anaerobic microbial consortium developed in our laboratory showed d echlorination of spiked polychlorinated biphenyls (PCBs), such as Aroc lor 1254 and a defined congener 2,3,4,5,6-pentachlorobiphenyl (CB) in the presence and the absence of lake sediment. Glucose and methanol we re used as carbon and energy sources. Highly chlorinated congeners (co ntaining >5 chlorines) such as penta-, hexa- and heptachlorobiphenyls were preferentially dechlorinated both in the presence and the absence of sediment with a simultaneous change in the distribution of relativ e amounts of tri- and tetrachlorobiphenyl congeners. The dechlorinatio n pattern and rates observed in both sediment and sediment-free condit ions were similar. In 24 weeks, almost 70% of the PCBs were dechlorina ted without accumulation of any specific PCB congeners. Monochlorobiph enyls were dechlorinated at a higher rate than di- and tetrachlorobiph enyls. (C) 1995 Elsevier Science Ltd. All rights reserved.