Abstract
Nine laboratories collaborated on the analyses of PCBs in chicken fat and DDT-PCB combinations in fish. Existing AOAC multipesticide methodology with GLC quantitation was employed. One solution containing a mixture of Aroclors 1254 and 1260 was analyzed by GLC only. The fish samples were subjected to a published silicic acid procedure for separating the DDT-PCB mixtures. The DDT analogs were quantitated before and after the separation. The PCB content was quantitated by total peak height and total area comparisons against appropriate Aroclor(s), using electron capture GLC, and additionally in 6 laboratories by total area comparisons, using halogen-specific detection. The electron capture GLC data demonstrated better accuracy and precision. The following PCB recoveries were obtained by using total peak height comparisons: 5 ppm mixed Aroclor solution, 100±4%; 8 ppm Aroclor 1242-fortified chicken fat, 101±13%; 7.5 ppm Aroclor 1248-fortified chicken fat, 96±9%; incurred Aroclor 1242 chicken fat, 9.2 ppm±8%; 6 ppm Aroclor 1254-fortified fish, 75±14%; 6 ppm Aroclor 1260-fortified fish, 75±15%; and an environmentally incurred residue in fish, 4.5 ppm±20%. The 2 Aroclor-fortified fish samples were concurrently spiked with the p,p′-isomers of DDE, TDE, and DDT at levels of 4, 1, and 3 ppm, respectively. After silicic acid separation the combined recoveries for these 2 samples were: DDE, 86±13%; TDE, 89±20%; and DDT, 84±17%. Environmentally incurred-DDT residues were recovered at 4.1 ppm±14% for p,p′-DDE, 0.7 ppm±24% for o,p′-DDT, and 2.7 ppm±17% for p,p′-DDT. The DDT values calculated before the silicic acid separation compared favorably with those summarized. The multiresidue method for chlorinated pesticides, 29.001–29.027, has been adopted official first action to include polychlorinated biphenyls in poultry fat and fish.
Psychrotolerant Bacteria Isolated from Arctic Soil That Degrade Polychlorinated Biphenyls at Low Temperatures