DDT residues in cod livers from the Maritime Provinces of Canada

The residues of DDT and its analogs were estimated in a number of cod liver samples (Gadus morhua) collected at six sampling sites off the Atlantic Coast of the Maritime Provinces of Canada during the summer of 1971. The residue levels indicated widespread distribution of DDT over the entire region sampled. Variations in the relative contributions of p,p'-DDE and p,p'-DDT to the total DDT residues (xiDDT) were noted and the tendency for these residues to preferentially accumulate in lipid rich tissues was demonstrated. The residue levels found in cod livers were compared to the residue levels determined in cod flesh taken from some of the same specimens and also to residue levels in commercially refined cod liver oils. Samples of each of these types were stored at -29 degrees C and analyzed in 1973 for DDT and PCB simultaneously. The xiDDT residues determined by both methods of analysis were compared.