Trace element (Cd, Cu, Hg, Se, Zn) accumulation and tissue distribution in loggerhead turtles (Caretta caretta) from the Western Mediterranean Sea (southern Italy)
Résumé
Cadmium (Cd), copper (Cu), mercury (Hg), selenium (Se) and zinc (Zn) were determined in the liver, kidney and muscle of 29 loggerhead turtles, Caretta caretta, from the South Tyrrhenian Sea (Western Mediterranean). Cd and Hg exhibited a wider range of concentration in the examined tissues than Cu, Se and Zn. For all the elements analysed, no significant differences (p > 0.05) were detected between males and females. Trace element concentrations were not influenced by the size of the specimen except Se in the liver, which was negatively correlated with the curved carapace length (p < 0.001). The distribution of the analysed elements was comparable to that reported in other marine vertebrates. Thus, the muscles generally displayed the lowest trace element burdens, with the exception of Zn reaching elevated concentrations as high as 176 µg g-1 dry wt. Kidneys displayed the highest Cd and Se mean concentrations (57.2 ± 34.6 and 15.5 ± 9.1 µg g-1 dry weight, respectively), while liver exhibited the highest Cu and Hg values (37.3 ± 8.7 and 1.1 ± 1.7 µg g-1 dry weight, respectively). Whatever the tissue considered, toxic elements had elevated coefficients of variation (i.e. from 60% to 177%) compared to the essential ones (i.e. from 14% to 65%), which is a consequence of homeostatic processes for Cu, Se and Zn. Globally, the concentrations of Hg remained low in all the considered tissues, which might be the result of low trophic level in sea turtles. In contrast, the diet of loggerhead turtles would result in a significant exposure to Cd. Highly significant correlations between Cd and Cu and Zn in the liver and kidney suggest that efficient detoxification processes involving MTs occur to prevent Cd toxicity in loggerhead turtles.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...