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3C - Fate and effects of TBT (WEP/173) TBT-induced imposex in neogastropods in the River Tyne estuary (UK) and an inshore dredged material site. Smith, Andy 1, Thain, John 1, Reed, Jacquie 1, Lucas, Shirley 1, Lauder, Nicky 1, 1 CEFAS, Burnham on Crouch, Essex, UK ABSTRACT- The condition known as imposex in female neogastropod molluscs is known to be induced by exposure to tributyltin (TBT). This study investigates the use of in situ caged organisms along the River Tyne, a UK estuary known to have historic TBT contamination. Caged populations of dogwhelks (Nucella lapillus) and mussels (Mytilus edulis), which acted as a food source for the whelks, were deployed at five locations. After six months the prevalence of imposex in dogwhelks at each location was calculated using the vas deferens sequence index (VDSI) and the relative penis size index (RPSI). Whole body tissue analysis for TBT was also conducted on the dogwhelks and mussels from each site. Sites within the estuary showed a strong induction of imposex, with a reduced imposex induction North and South of the mouth of the estuary. These results reflect the pattern of TBT concentrations measured in the caged dogwhelk and mussel tissues. In addition, the pervasiveness of imposex in natural populations of the red whelk (Neptunea antiqua) and the common whelk (Buccinum undatum) was recorded at the Tyne dredged material site, indicating exposure of these two species to TBT contaminated sediments. The results are discussed in relation to the occurrence of imposex at other UK sites and the need for further monitoring at TBT impacted locations. Key words: TBT, Imposex, Cage Studies, Neogastropods |
