Accumulation and tissue distribution of heavy metals and essential elements in loggerhead turtles (Caretta caretta) from Spanish Mediterranean coastline of Murcia Silvia Jerez a , Miguel Motas a, * , Régulo Ángel Cánovas a , Jesús Talavera b , Ramón Miguel Almela b , Alejandro Bayón del Río b a Department of Toxicology, Faculty of Veterinary Medicine, University of Murcia, Campus of Espinardo, 30100 Murcia, Spain b Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University of Murcia, Campus of Espinardo, 30100 Murcia, Spain article info Article history: Received 2 June 2009 Received in revised form 16 October 2009 Accepted 27 October 2009 Available online 2 December 2009 Keywords: Loggerhead sea turtles Heavy metals Essential elements Mediterranean sea abstract Sea turtles are of increasing interest as potential bioindicators of the heavy metal pollution in marine eco- systems. In the present work, concentrations of heavy metals and essential elements (As, Cd, Hg, Pb, Se, Zn) in different organs and tissues (liver, kidney, muscle, bone, blood, central nervous system and skin) of loggerhead sea turtles (Caretta caretta) were determined from stranded animals found along the Spanish Mediterranean coastlines of Murcia. Relatively high average levels of As (skin: 52.13 lgg À1 dry weight; muscle: 40.95 lgg À1 dry weight), and especially high individual levels of Zn in muscle tissue (1002.4 lgg À1 dry weight) were detected. Furthermore, a significant degree of organotrophism of Cd was observed in kidney tissue. The concentrations detected, the distribution among the tissues and the differences observed between juvenile and adult specimens are generally compatible with chronic expo- sure to the elements studied, whilst levels produced by acute exposure were ruled out. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Currently, three of the seven marine species of turtles can still be found in the Mediterranean: the loggerhead sea turtle (Caretta caretta), the green turtle (Chelonia mydas) and the leatherback tur- tle (Dermochelys coriacea). Of the three, the loggerhead sea turtle is the most abundant (Margaritoulis et al., 2003; Franzellitti et al., 2004) and the only one still nesting on the Spanish coastline (Vale- iras et al., 2001; CREMA, 2001). Among others, the greatest threats to the survival of marine tur- tles in many parts of the world include, marine pollution, loss of nesting habitats, accidental capture by surface fishing with long- line hooks (Cocco et al., 1988; Argano et al., 1992; Aguilar et al., 1995; Camiñas and De La Serna, 1995) or to lesser extent other types of fishing (Cocco et al., 1988; Argano et al., 1992; Bertolero, 1992, 2003). Worldwide, the loggerhead sea turtle is currently classified as an ‘‘endangered” species (IUCN, 2007), and its situa- tion is probably critical in the Mediterranean sea, where the popu- lations of all nesting turtles was already considered as poor or very poor two decades ago (Groombridge, 1990). A marine basin en- closed and surrounded by highly industrialised countries repre- sents a high risk area in terms of the build-up of toxic compounds (Bacci, 1989; Meadows, 1992; Kuetting, 1994; Borrel et al., 1997). Even though some essential elements are natural components of rocks and soil, which find their way into the marine environment as a consequence of weathering and erosion (Garrett, 2000), due to industrialization, unnatural quantities of these ele- ments have been released, and continue to be released into the sea altering the natural biological equilibrium (Haynes and John- son, 2000). Many of them are biologically essential but they can be toxic to biota above certain exposure thresholds (O’Shea and Geraci, 1999). Therefore, they may cause adverse effects in organ- isms at the top of the marine food-chain (Cardellicchio et al., 2000), particularly on those long living species such as sea turtles, which have the potential to accumulate these contaminants (Caurant et al., 1999; Anan et al., 2001). Although the concentration of metals in the water column is generally low due to their poor solubility, precipitation in sedi- ments will expose bottom-dwelling organisms, in which metals may reach toxic levels (Mas and Azcue, 1993). The interest in monitoring the amount of heavy metals and essential elements in turtles with a view towards the species pres- ervation (Sakai et al., 1995), is demonstrated by the large number of recent studies in the Mediterranean area (Storelli et al., 1998a,b, 2005; Franzellitti et al., 2004; Maffucci et al., 2005; Andreani et al., 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.10.062 * Corresponding author. Tel.: +34 868 883646; fax: +34 868 884147. E-mail address: motas@um.es (M. Motas). Chemosphere 78 (2010) 256–264 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere