Microbial potential for the anaerobic degradation of simple aromatic compounds in sediments of the Milwaukee Harbor, Green Bay and Lake Erie

The ability of microbial populations to mediate the anaerobic transformation of six aromatic compounds in sedi ments from the Milwaukee Harbor, Green Bay, and Lake Erie was examined Sediment slurries were incubated in an anaerobic mineral salts medium that was amended with multiple electron acceptors, including manganese(IV) and Fe(III) oxides, and the concentrations of the aromatic substrates were followed over a six to 18 month period Most sediment samples showed a com plete loss of benzoate and 4 hydroxybenzoate within approximately two months Benzoate losses were partially to markedly inhibited by the addition of molybdate, whereas losses of 4 hydroxybenzoate were not molybdate inhibited Significant losses of aniline, 3 chlorobenzoate, and 2,4‐dichlorophenoxyacetic acid were observed with many of the sediments after approximately 18 months Molybdate markedly inhibited the metabolism of 3 chlorobenzoate with all sediments, and of aniline with some sed lments Increases in free chloride, which are indicative of reductive dechlorination were coincident with losses of 3 chlorobenzoate and 2,4 dichlorophenoxyacetic acid No significant metabolism of 4 chlorobenzoate was apparent in any of the sediments Over all, the results indicate that microbes with the ability to degrade at least certain aromatic compounds are present at various sites within these environments