Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Imposex levels and butyltin compounds (BTs) in Hexaplex trunculus (Linnaeus, 1758) from the northern Adriatic Sea (Italy): Ecological risk assessment before and after the ban Federica Cacciatore a,⁎ , Rossella Boscolo Brusà a , Seta Noventa a , Camilla Antonini a , Vanessa Moschino b , Malgorzata Formalewicz a , Claudia Gion a , Daniela Berto a , Massimo Gabellini c , Maria Gabriella Marin d a ISPRA - Institute for Environmental Protection and Research, Loc. Brondolo, 30015 Chioggia Venice, Italy b CNR, ISMAR, Arsenale Tesa, 104, Castello 2737-F, 30122 Venice, Italy c ISPRA - Institute for Environmental Protection and Research, via Vitaliano Brancati, 48, Rome, Italy d University of Study of Padua, Department of Biology, Via U. Bassi, 58/B, 35131 Padua, Italy ARTICLE INFO Keywords: Vas Deference Sequence Index Relative Penis Size Index Bioaccumulation Water Framework Directive Ecological Quality Ratio Venice Lagoon ABSTRACT The aim of this study was to compare imposex and butyltin compounds (BTs) data, collected before and after the organotin ban in 2008, in order to assess temporal and spatial variation of the phenomenon, the decline of BT contamination, and the effects on Hexaplex trunculus population in the coastal area of the northern Adriatic Sea, close to the Venice Lagoon. Both in marine and in lagoon sites, the results obtained in 2013–2015 showed a significant decline in the incidence of imposex in respect to those from the 2002 survey. In 2002, lagoon samples exhibited Relative Penis Size Index (RPSI) higher than marine samples, whereas no differences were detected in the recent survey, when all RPSI values were below 0.6%. Vas Deference Sequence Index (VDSI) mean values were over 4 before the ban introduction and below this value after that, indicating more critical conditions for gastropod population in 2002 rather than in 2013-15. Percentage of sterile females was up to 69% in 2002, whilst in the more recent survey no sterile female was found. Range of BT concentrations in gastropods de- creased from 252 to 579 to 16–31 ng∑BT/g d.w. BT body burdens varied according to a gender dependant pattern, with higher concentrations observed in females than in males. A first attempt to propose a classification based on BT impact on H. trunculus, according to the Water Framework Directive, revealed that most sites were in Bad ecological status before the ban and attained a Poor/Moderate status after that. 1. Introduction Imposex is a phenomenon described for the first time by Smith (1971), which consists of the superimposition of male sexual characters onto female gonochoristic gastropods. It is one of the most studied ef- fect of tributyltin (TBT) which affected more than 260 species of gas- tropods, and it is used as TBT specific biomarker all over the world, mostly in those species which have shown a significant correlation between the degree of morphological alterations and the concentrations of the contaminant (Titley-O′Neal et al., 2011). In most of caenogas- tropoda species, imposex can lead to population decline as a con- sequence of sterility and reproduction failure (Bryan et al., 1986). Among these species, Hexaplex trunculus (Linnaeus, 1758) has been used as a bioindicator of butyltin (BT) pollution in Mediterranean areas, such as along the coasts of Malta (Axiak et al., 1995, 2000, 2012), Tunisia (Lahbib et al., 2008, 2009, 2011; Anastasiou et al., 2016), Croatia (Garaventa et al., 2006, 2007; Carić et al., 2016; Erdelez et al., 2017) and Italy (Terlizzi et al., 1998, 1999, 2003; Chiavarini et al., 2003; Pellizzato et al., 2004; Garaventa et al., 2006, 2007; Anastasiou et al., 2016), both before and after the TBT global ban adopted in 2001 by the International Convention on the control of harmful antifouling systems on ships (AFS-Convention 2001). The global ban came into force in September 2008 (IMO, 2001), but in the European Union it was enacted by the EC Regulation 782/2003 which totally interdicted the application of organotin compounds on ships after 1st of July 2003 and forced the eradication of these compounds from ships from 1st January 2008 (EC, 2003). These regulations arose from evidences of organotin high toxicity to many aquatic organisms and significant long-term ecological impacts at very low concentrations on non-target marine species (Axiak et al., 2012). Due to their persistence, toxicity and http://dx.doi.org/10.1016/j.ecoenv.2017.09.027 Received 17 May 2017; Received in revised form 7 September 2017; Accepted 11 September 2017 ⁎ Corresponding author. E-mail address: federica.cacciatore@isprambiente.it (F. Cacciatore). Ecotoxicology and Environmental Safety 147 (2018) 688–698 0147-6513/ © 2017 Elsevier Inc. All rights reserved. MARK