Bacterial Degradation of Polychlorinated Biphenyls II. Rate Studies

Polychlorinated biphenyls (Aroclor 1221, 1242 and 1254) at concentrations up to 0.1% in glucose did not inhibit the growth of lake water bacteria. The bacteria used Aroclor 1221 and 1242 but not 1254 as sole carbon and energy sources for growth. Less than 1% of lake water bacteria, however, possess this ability. Seven bacterial isolates from Aroclor agar plates were identified; five belonged to Achromobacter sp. and two were Pseudomonas sp. The metabolic breaksown of Aroclor 1221 was followed. THE MIXTURE WAS COMPLETELY DEGRADED INTO SEVERAL LOW MOLECULAR WEIGHT COMPOUNDS AFTER ONE MONTH INCUBATION. Unchlorinated biphenyl was degraded at a faster rate than 2-chlorobiphenyl and 4-chlorobiphenyl isomers.