Butyltins concentration levels and imposex occurrence in snails from the Sicilian coasts (Italy) S. Chiavarini, P. Massanisso, P. Nicolai, C. Nobili, R. Morabito * ENEA C.R. CASACCIA––TEIN/CHIM, Via Anguillarese, 301-00060 Rome, Italy Received 2 January 2002; received in revised form 8 August 2002; accepted 9 September 2002 Abstract Two sampling campaigns have been carried out along the Sicilian coasts within the frame of a European project (Hic-TBT) financed by the LIFE programme. Snails and sediments have been sampled at 5 stations, characterised by verylow(Usticanaturalseareserve),low(Usticaharbour),intermediate(CastellamareandTerminiImerese)andhigh shipping densities (Palermo). Biological and chemical analyses were carried out in order to evaluate the incidence of imposex occurring in snails, and the concentration levels of organotins in sediment and snail samples. Despite the low organotin concentration levels in sediment and snail samples, the results show that imposex is widespreadaroundSicily.Infourlocationsalmostallfemalesnailswereaffectedbyimposexatadvanceddevelopment stages, even in areas with a fairly low shipping density. Only in the natural sea reserve of Ustica Island imposex was relatively less severe. Finally a logarithmic correlation between TBT and imposex stages was observed. Ó 2002 Elsevier Science Ltd. All rights reserved. Keywords: Tributyltin; Gastropods; Hexaplex trunculus; Antifouling paints; Sediments; Mediterranean Sea 1. Introduction Thereleaseoftributyltin(TBT)frommaritimetraffic represents one of the main problems of direct, diffuse and continue contamination of the marine environment of the last 20 years. The high toxicity of this compound towards non- target organisms, together with its high tendency to be accumulated in marine organisms, have created signifi- cant environmental problems with economic conse- quences too. ThefirstevidenceofenvironmentaldamagesbyTBT released by antifouling paints appeared in Arcachon (France) where, from 1975 to 1982, oyster production wasseverelydisturbedbyalackofreproductionandthe appearance of shell calcification anomalies in adult oysters with high economic losses (Alzieu, 1986; Ruiz et al., 1996). Declineofgastropodpopulationshasbeenregistered worldwide as a consequence of the induction of the imposex effect by TBT, consisting in a superimposition of male sexual characteristics on female organisms. In particular, high occurrence of imposex has been evi- denced in the North Sea, in Japan, India, etc. (ten Hallers-Tjabbesetal.,1994).Althoughthepossibilityof the induction of imposex by other pollutants cannot be ruled out (Matthiessen and Gibbs, 1998), all the avail- able environmental evidence points to TBT as the sole causal agent for imposex in marine organisms. Both exposuretimeandTBTconcentrationarekeyfactorsin determining the kinetics of the development of imposex (Davies, 2000). Imposex in Mediterranean gastropods is poorly studied: the first observations of this phenomenon in Hexaplex trunculus were provided by Martoja and Chemosphere 50 (2003) 311–319 www.elsevier.com/locate/chemosphere * Corresponding author. Tel.: +39-6-30484933; fax: +39-6- 30484525. E-mail address: morabito@casaccia.enea.it (R. Morabito). 0045-6535/03/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII:S0045-6535(02)00601-X