METABOLISM OF DIFFERENT PCB CONGENERS IN PLANT-CELL CULTURES

The metabolism of 10 different congeners of polychlorinated biphenyls (PCBs) was tested in cell cultures of 12 different plant species. The rate of metabolism was determined through comparison with cells inacti vated by treatment with perchloric acid. The metabolism of defined PCB congeners was strongly dependent on the plant species. In particular, two Fabaceae species exhibited high capacities for metabolizing diffe rent congeners. Except for PCB 15 (4,4'-dichlorobiphenyl), it was show n that a lower chlorination grade is associated with higher metabolism rates. Also, it was shown that substitution and molecular configurati on play an important role in the metabolism of PCBs in plants. In stud ies with C-14-PCB 1 (2-chlorobiphenyl) in soybean cultures, one dihydr oxylated and six different monohydroxylated compounds were detected af ter acid hydrolysis of polar metabolites (conjugates). Hydrolysis of m etabolites of C-14-PCB 52 (2,2',5,5'-tetrachlorobiphenyl) in wheat cel l cultures yielded four monohydroxylated and three dihydroxylated meta bolites.