This study examined the accumulation of tributyltin (TBT) and the occurrence of intersex in the marine snail Littoraria scabra collected from two locations in Indonesia. The snails accumulated TBT when exposed to contaminated water and sediment/food at concentrations of 1, 2, and 3 ppb, with higher accumulation at 3 ppb. Measurement of intersex stage showed higher levels in snails from Bitung Coastal Waters compared to Amurang Bay, indicating greater TBT contamination. The study concludes that L. scabra can be used as a biomonitor for TBT contamination through measurement of accumulation and intersex occurrence.

1. Accumulation of Tributyltin (TBT) and Intersex Occurrence as TBT-contaminated indicator on the marine snail Littoraria scabra (Gastropoda: Mollusca) Laboratory of Toxicology and Marine Pharmaceutics Faculty of Fisheries & Marine Sciences Sam Ratulangi University, Manado, North Sulawesi, Indonesia By Markus T. Lasut TBT-contaminated indicator Presented in : International Conference & Workshop XI of “Tropical Marine Mollusc Programme”, sponsored by DANIDA at Kodaikal, Rameswaran and Tuticorin-Tamilnadu, India. 28 September – 8 Oktober, 2000

5. OBJECTIVES 1. Accumulation of TBT to understand two different pathways of TBT accumulation (via TBT-contaminated water & TBT-contaminated sediment and food) 2. Intersex occurrence to measure and compare intersex stage between two different locations Residues of TBT accumulated in the body of the animals were measured qualitatively using Tin-Layer Chromatography technique

9. RESULTS Visual Observation on L. scabra contaminated to TBT at different pathways yes (before 9 days) yes, very rough produce mucus Behaviour : yes (before 9days) Water condition: very rough Other : produce mucus 3 ppb TBT yes (before 9 days) yes, rough produce mucus Behaviour : yes (before 9days) Water condition: yes, rough Other : produce mucus 2 ppb TBT no (after 9 days) no -- Behaviour : no (after 9 days) Water condition: no Other : -- 1 ppb TBT no no -- Behaviour : no Water condition: no Other : -- Control TBT-contaminated sediment & food TBT-contaminated water Treatments Pathways

10. RESULTS Qualitative measurement of TBT residue accumulated in the body (soft part) of L. scabra (continued) no : undetected residues yes : detected residues yes yes no TBT-contaminated sediment & food yes yes no TBT-contaminated water 3 2 1 ways TBT Concentration (ppb) Path-

11. Intersex Determination in Littoraria scabra RESULTS (continued) ISI > 1.0 indicate that at least some of the females in the sample are sterilized due to intersex development 0.27 9 29 E 0.50 17 28 D 0.93 22 31 C 0.76 13 30 B 0.15 5 26 A Bitung Coastal Water (BCW) 0.08 5 36 Amurang Bay ISI Intersex (%) Number of Samples (Female) Locations

12. Locations ISI Values Intersex Intensity Comparison Qualitative residue of TBT in body of L. scabra RESULTS (continued) no : undetected residues, yes : detected residues no yes yes yes no no E D C B A Bay Bitung Coastal Waters Amurang

15. ACKNOWLEDGEMENT I am greatly indebted to the DANIDA sponsored Tropical Marine Mollusc Programme (TMMP) for the possibility to present this paper at the 11 th TMMP Conference/Workshop at Kodaikanal, Tamilnadu, India, to Dr. Jorgen Hylleberg for his kindly help and advice. I am particularly grateful to the Organizing Committee, Dr. P. Edward and Dr. A. Murugan for their warm welcome and hospitality during the congress. “ Thank you”