Environmental assessment and ecotoxicological implications of the co-elution of pcb congeners 132 and 153

Concentrations of polychlorinated biphenyl congeners 132 and 153, which can co-elute on nonpolar columns, were determined in some commercial products and various sample matrices from the aquatic ecosystem. Ratios of 132:153 were generally about 30:70 for most of the Aroclors monitored. Congener concentrations generally increased with increasing trophic levels which is consistent with previous PCB trophodynamic studies. Ratios generally ranged from about 30:70 in sediment and water, 25:75 in invertebrates, 1(1:90 in fish, 5:95 in piscivorous birds, 15:85 in whales and 1:99 in walrus and seals. Changes in ratios could be due to the differences in physical and chemical properties between these congeners, and biochemical adaptations by some mammals. The change in ratios could have ecotoxicological significance because CB 153 has higher TCDD toxic equivalents and greater Ah receptor binding than CB 132.