Effect of hydrogen on the pathway and products of PCB dechlorination.

The pathway and products of reductive dechlorination of 2,3,4-chlorobiphenyl by Hudson River sediment microorganisms were altered by H2. Under H2/CO2, 2,3,4-CBP was dechlorinated to 2,4-,2,3-, and then 2-CBP. On the other hand, under N2, the same organisms yielded only 2,4-CBP as they did under N2/CO2. Dechlorination was not inhibited by a single or periodic addition of a methanogenic inhibitor, 2-bromoethanesulfonic acid under all gas atmospheres and thus, methane production was not necessary for dechlorination.