Disposition of toxic PCB congeners in snapping turtle eggs: expressed as toxic equivalents of TCDD
Studies of snapping turtles, taken from the region of the Upper Hudson River, in New York State, revealed exceedingly high levels of PCBs in the adipose tissue. There is evidence to suggest that large reserves of fat provide protection against chlorinated hydrocarbon toxicity. Such storage may protect snapping turtle eggs from disposition of toxic PCB congeners and account for the apparent absence of reports regarding detrimental effects on the hatchability of eggs from turtles living in the vicinity of the upper Hudson River. The present study was undertaken to determine if indeed these eggs are protected against disposition of toxic PCB congeners by the presence of large reserves of fat. Although tissue volumes play an important role in determining the initial site of disposition, the major factor controlling the elimination of these compounds involves metabolism. For simple halogenated benzenes as well as for more complex halogenated biphenyls, oxidative metabolism catalyzed by P-448, occurs primarily at the site of two adjacent unsubstituted carbon atoms via arene oxide formation leading to the formation of water soluble metabolites. Toxicological studies have demonstrated that the most toxic PCB congeners, isosteriomers of tetrachlorodibenzo-p-dioxin (TCDD), require no metabolic activation. These compounds have chlorine atoms in the meta and para positions of both rings. It may be concluded that the structures of PCB congeners and isomers which favor induction of cytochrome P-448 are also those which are toxic and resist metabolism. It is the objective of the present study to determine if the heavy fat bodies of the female turtle provide a sufficiently large sink to retain the toxic congeners and prevent their incorporation into the eggs.
- Research Organization:
- State Univ. of New York, Albany (USA)
- OSTI ID:
- 5378526
- Journal Information:
- Bull. Environ. Contam. Toxicol.; (United States), Vol. 39:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ADIPOSE TISSUE
CHEMICAL ANALYSIS
CHLORINATED AROMATIC HYDROCARBONS
GAS CHROMATOGRAPHY
METABOLISM
EGGS
CYTOCHROMES
DIOXIN
ENZYME INDUCTION
TURTLES
ANIMAL TISSUES
ANIMALS
AROMATICS
BODY
CHROMATOGRAPHY
CONNECTIVE TISSUE
GENE REGULATION
HALOGENATED AROMATIC HYDROCARBONS
HETEROCYCLIC COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PIGMENTS
PROTEINS
REPTILES
SEPARATION PROCESSES
TISSUES
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology