THE INGESTION AND ACCUMULATION OF ZINC, COPPER, LEAD,CADMIUM AND ARSENIC IN THE YANGTZE FINLESS PORPOISE,NEOPHOCAENA PHOCAENOIDES ASIAEORIENTALIS

Estimated daily and weekly intakes of trace element for 3 captive Yangtze finless porpoises were calculated, based on the rearing records and concentration of zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd) and arsenic (As) in food crucian carp ( Carassius auratus ) in Institute of Hydrobiology, the Chinese Academy of Sciences. Ranges of the estimated daily intakes of trace element studied per porpoise were 21.7 - 49.52 mg for Zn, 1.91 -2.98 mg for Cu,0.21 -3.98 mg for Pb,0.04-0.20 mg for Cd and 0.39-0.99 mg for As. The estimated weekly intakes calculated of essential Cu, Zn were similar to Provisional Tolerance Weekly Intake (PTWI) for human (suggested by WHO/FAO). However, those of highly toxic Pb, Cd and As were much more than the PTWI of human. Also, the distribution patterns and levels of these trace elements were ascertained in a Yangtze finless porpoise died accidentally in Tian-e-zhou water in Hubei province. Tendency of tissue or organ specific accumulation of studied elements was found in finless porpoise, such as in the liver for Cu (50.7μg/g dry weight) and As (0.80μg/g dry weight), the skin for Zn (579μg/g dry weight) and the kidney for Cd (7.7μg/g dry weight) . Special requirement for corresponding elements may mainly contribute to this tendency, rather than the difference between fresh water and marine environment. Our study suggests that the food safety criterion for captive cetaceans (especially in aquariums) is necessary for controlling the contamination of pollutants from food sources. Further study on the relation between trace element and life function should be one of most important field for the development of cetacean nutritional chemistry and ecological toxicology.