Residues of polychlorinated biphenyls (PCB) in fatty foods of the Canadian diet.

Market basket samples representative of food from six Canadian cities were surveyed from 1992 to 1996. Fifty composites of fatty foods, prepared for consumption were analysed for 40 PCB congeners by gas chromatography-mass spectrometry. Fish and butter contained the highest total PCB concentrations, while milk and infant foods contained the lowest. The dairy and meat composites were major contributors to the total PCB intake of 5.7 ng/kg/day, and to the TEQ (2,3,7,8-tetrachloro-p-dibenzodioxin equivalent) intake of 0.11 pg/kg/day. The pattern of congeners was similar for the different food groups with the exception of fish, which contained less tri- and tetra-chlorinated biphenyls and more of the hexachlorinated congener No. 153.