MEPS 171:275-284 (1998)  -  doi:10.3354/meps171275

Pharmacokinetics and distribution of dietary tributyltin compared to those of methylmercury in the American plaice Hippoglossoides platessoides

Claude Rouleau1,*, Charles Gobeil1, Hans Tjälve2

1Department of Fisheries and Oceans, Maurice Lamontagne Institute, PO Box 1000, Mont-Joli, Quebec G5H 3Z4, Canada
2Swedish University of Agricultural Sciences, Faculty of Veterinary Medicine, Department of Pharmacology and Toxicology, Biomedicum Box 573, S-75123 Uppsala, Sweden

ABSTRACT: Pharmacokinetics and distribution of a 5 µg dietary dose of tributyltin (113Sn-TBT) and methylmercury (Me203Hg) were studied over 42 d in the American plaice Hippoglossoides platessoides, using in vivo gamma counting, whole-body autoradiography, and a 2-compartment model. The average retention efficiency of TBT was 42%, compared with 88% for MeHg. Both organometals were distributed to the entire body of the fish. Distribution proceeded at a faster rate for TBT, 95% of the steady state distribution being reached within 5 to 10 d, compared with 29 to 41 d for MeHg. Elimination of TBT was characterised by half-life values ranging from 15 to 77 d. Absorption of dietary TBT from the intestinal lumen appears to be limited by its molecular size, whereas its fast translocation rate in the body of fish might be related to specific properties of the intestinal epithelium-blood interface or to co-transport with lipids. Our data also indicated that butyltins in the viscera were partitioned between 2 kinetically distinct pools; one that was eliminated rapidly and one that was stored or eliminated at a very slow rate, probably as a consequence of TBT metabolism. The overall biomagnification factor for the transfer of TBT from sediments to benthic invertebrates to the American plaice may be >1. This indicates that the trophic transfer of sedimentary TBT in the marine benthic food web is potentially significant.

KEY WORDS: Tributyltin · Methylmercury · Food · Uptake · Pharmacokinetics · Fish · American plaice · Benthos · Food web

Full text in pdf format