Comparison of organochlorine residues in wildlife must often be made to regulatory standards or to values of known biological significance; this is difficult when dissimilar tissues are analyzed and results are expressed on different bases. To relate levels in the different tissues used for regulatory and monitoring purposes and for biological assessments, we exposed American black ducks to mixtures of three organochlorines. Differences in residue burdens among tissues were not statistically significant when levels were expressed on a lipid weight basis. Levels of heptachlor and Aroclor 1254 in one tissue can be accurately predicted from those in another; such predictions for endrin are less reliable. Lipid weight based residue concentrations in wings may be used to predict whether levels in fat exceed residue standards set for human health or approach those associated with effects on populations of species sampled.
'Action Level' (0.3 ppm) Includes: American widgeon, Mareca americana (4), pintail, Oxyura jamaicensis (2), gadwall,
Anas strepera (2), mallard, Anas platyrhynchos (1), greenwing teal,
Anas carolinensis (1).
2 Assumes that whole bodies have the same percentage lipid as wings.
3 Assumes that the man lipid content of fat is 85.1%, based on data of Table I. 4 ND = not detected; detection limits were 0.05 ppm for wings and 0.005 ppm for fat.