Umbhalo Waphansi

a Ama-PCB (polychlorinated biphenyls), njengoba aqala ukusetshenziswa kakhulu kusukela ngawo-1930, awuhlobo olufanayo lwezinto ezinamafutha ezingaphezu kuka-200 ezisetshenziswa emafutheni okugcoba, kopulasitiki, ekuhlukaniseni ugesi, emithini eyizibulala-zinambuzane, oketshezini lokugeza izitsha neminye imikhiqizo. Nakuba ukukhiqizwa kwe-PCB manje sekuvinjelwe emazweni amaningi, sekukhiqizwe amathani aphakathi kwesigidi esisodwa nezimbili kakade. Ama-PCB alahliwe aye abangela ubuthi obuye bangena endaweni ezungezile.