Distribution of Heavy Metal Residues in Some Tissues of Caretta caretta (Linnaeus) Specimen Beached Along the Adriatic Sea (Italy)

At the present time there are seven marine turtle species all over the world. Among these only three are present in the Mediterranean Sea: the Loggerhead (Caretta caretta), Green (Chelonia mydas) and Leatherback (Dermochelys coriacea ) (Arnold and Burton, 1985). Caretta caretta is regarded as threatened, a term applied to species somewhat further from extinction (Waldichuk, 1987), and is therefore protected by the authorities in all countries in which this species is present. In Italy, it has been protected since February 24, 1976 (G.U., 1993). Different factors are causing the decrease in the number of this turtle: i) coastal anthropization, that makes places unsuitable for nidification (in the Mediterranean Sea this reptile nidifies above all on the island of Zakinthos in the Ionian Sea and, along the South-East coastal area of Turkey) (Jones, 1990); ii) the use of eggs as food in several countries (Nishimura and Nakahigashi, 1990; Hutchinson and Simmonds, 1991); iii) the casual capture of young and adult specimen during the swordfish and tuna fishing campaign (Venizelos, 1991; Groombridge, 1989) and finally iv) the remarkable problem of marine pollution. Most of the studies carried out on marine turtles concern the presence of plastic, glass and paper. As a matter of fact fragments of plastic, glass and pieces of paper were found in the intestine of some Caretta caretta specimens, caught along coasts of the Azores, and of Dermochelys coriacea specimens, caught along North-West European coasts (Bourne, 1985; Gramentz, 1988; Wehle and Coleman, 1983; Bjorndal et al., 1994). As far as the presence of chemical pollutants, such as heavy metals is concerned, not much has been published so far in the literature (Davenport and Wrench, 1990; Witkowski and Frazier, 1982; Aguirre et al., 1994). Most of the available papers concern pollutant residues in eggs (Stoneburner et al., 1980; Blumton et al., 1990; Clark and Krynitsky, 1985; Vazquez et al., 1997; Sakai et al., 1995; Bishop et al., 1991). The aim of this work is to assess the presence of heavy metals (Hg, Pb, Cd, Cr, As, Se) in different tissues of Caretta caretta specimens beached along Italian coasts (S. Adriatic Sea).