Determination of polychlorobiphenyls in Venice Lagoon sediments I. Moret a,b, * , R. Piazza b , M. Benedetti c , A. Gambaro a,b , C. Barbante a,b , P. Cescon a,b a CNR, c/o Dipartimento di Scienze Ambientali, Centro di Studio sulla Chimica e le Tecnologie per l'Ambiente, Universit  a Ca' Foscari, Dorsoduro 2137, 30123 Venezia, Italy b Dipartimento di Scienze Ambientali, Universit  a Ca' Foscari, Dorsoduro 2137, 30123 Venezia, Italy c c/o Dipartimento di Scienze Ambientali, CINSA, Consorzio Interuniversitario Nazionale per le Scienze Ambientali, Dorsoduro 2137, 30123 Venezia, Italy Abstract Polychlorinated biphenyl PCBs) congeners were measured in 14 sediment samples collected at ®ve sites in the Venice Lagoon selected on the basis of a supposed diversity of inputs and of pollution levels. The PCBs were deter- mined after a sonication assisted extraction by gaschromatography mass spectrometry GCMS). The sum of the congener concentrations determined in the samples range from 4.05 to 239.15 ng/g on a dry weight basis. The con- centrationvaluesareveryvariablebothcomparingthesitesandcomparingdierentsamplesfromthesamesiteandcan beconnectedtothesandpercentageinthesedimentsamples.Thecorrelationmatrixobtainedfromdatamatrixusing thecongenerconcentrationsasvariablesshowshighvalues,mostlybetween0.964and1,suggestingthatthepatternof thePCBcongenersandtheratiosamongtheconcentrationsinVeniceLagoonsedimentsaremoreorlessconstant;the samples dier only in the concentration level. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: PCBs; Sediment; Venice Lagoon; GCMS; PCA 1. Introduction Polychlorinated biphenyls PCBs) are ubiquitous environmental contaminants characterized by their persistenceintheenvironmentIwataetal.,1993;Fuoco et al., 1994; Harner et al., 1998). Further features that haveattractedtheinterestofthescienti®ccommunityto thesecompoundsincludetheirtoxicity,whichdiersfor each congener, ranging from highly toxic values like those of dioxins) to moderately toxic and their accu- mulation in the lipid tissues, which can have an impact on human health through the food chain Facchetti, 1993). PCBs are a class of 209 chemical compounds, widely used as dielectric ¯uids in transformers and ca- pacitors, hydraulic ¯uids, ¯ame retardants, organic dil- uents and in many other applications Erickson, 1997). Commercial mixtures contain 70±90 dierent isomers, but not all are found in detectable quantities in the en- vironment. Due to their hydrophobic nature they accu- mulate in sediments and biota in the acquatic environment. TheVeniceLagoonextendsforabout549km 2 ,along the northwest coast of the Adriatic Sea. It is a shallow basin, connected to the sea through three entrances, 400±900 m wide. About 3:1±4:5  10 8 m 3 of water is exchangedbetweenthelagoonandtheseaduringatidal cycle, but only the water in areas near the entrances is signi®cantly exchanged with the sea water. The Venice Lagoon is located in a highly populated area and is Chemosphere 43 2001) 559±565 * Corresponding author. Tel.: +39-41-2578506; fax: +39-41- 2578549. E-mail address: moret@unive.it I. Moret). 0045-6535/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII:S0045-653500)00407-0