Concentrations and enantiomeric fractions of chiral polychlorinated biphenyl (PCB) congeners in Standard and Certified Reference Materials, and the biota of the Lac La Biche (LLB) aquatic food web were evaluated in order to ascertain the occurrence of PCB bioaccumulation and biotransformation. Bioaccumulation of PCB congeners was observed in biota of the LLB food web. In forage fish, there was little evidence of biotransformation of chiral PCBs. In predatory fish and piscivorous birds, extensive bioprocessing of PCB 95, 91, and 149 was observed, indicated by nonracemic enantiomeric fractions of these congeners. This may indicate the occurrence of cytochrome P-450 mediated biotransformation of these congeners. Bioaccumulation of both chiral and achiral PCB congeners was observed in fish of the LLB food web. Evidence of enantioselective maternal transfer of PCB congeners 95 and 149 from mother to egg was observed, as indicated by statistically different EFs observed in double-crested cormorants.