An integrated study of endocrine disruptors in sediments and reproduction-related parameters in bivalve molluscs from the Biosphere's Reserve of Urdaibai (Bay of Biscay).

Urdaibai was declared a Biosphere's Reserve by UNESCO in 1984. Because we observed a high prevalence of hermaphroditism in mussels sampled in Urdaibai in March 2004, we started the present research work in order to determine the presence of endocrine disruptors (EDs) in sediments and to study possible EDs effects on mussels and oysters using gonad index and vitellogenin (VTG)-like protein levels as biomarkers. Samples were collected at five localities in April 2007 and 2008, and in October 2007.