Uses of subcellular metal distribution in prey to predict metal bioaccumulation and internal exposure in a predator.
In the present study, rock oysters (Saccostrea cucullata) were first exposed to cadmium and zinc for two weeks to modify their subcellular metal partitionings. The relationship between subcellular metal (Cd and Zn) partitioning in the oysters and metal bioaccumulation and fractionation in predatory gastropods (Thais clavigera) was then examined by feeding to the predator oysters that were preexposed to metal for two to four weeks. We also investigated the relationship between the PAM in the oysters and the biochemical biomarkers in the gastropods. Thais clavigera accumulated Cd effectively from their prey, but no correlation was found between the Cd body concentrations in T. clavigera and the internal metal partitioning in the prey. A significant positive correlation was found between the Cd in the trophically available metal (TAM) fraction of oysters and the Cd in the metal-sensitive fraction of T. clavigera and between the Cd in the TAM fraction of oysters and the metallothionein induction in whelks. Zinc was highly regulated by both S. cucullata and T. clavigera, and their Zn body concentrations remained constant throughout the exposure period. No relationship between Zn bioaccumulation and any of the subcellular fractions was found. The present study may lead to a better understanding of the dietary metal exposure mechanism.
Cheung
Ma-Shan
MS
Atmospheric Marine Coastal Environment Program, Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Wang
Wen-Xiong
WX
D000818:Animals; D001822:Body Burden; D008670:Metals / Q000378:metabolism*; D011235:Predatory Behavior; D013347:Subcellular Fractions / Q000378:metabolism*
D008670:Metals