Trace elements in loggerhead turtles (Caretta caretta) stranded in mainland Portugal: Bioaccumulation and tissue distribution Lídia Nicolau a, b, * , Sílvia S. Monteiro a, b , Andreia T. Pereira b , Ana Marçalo a, b , Marisa Ferreira b, c , Jordi Torres d, e , Jos  e Vingada b, c, f , Catarina Eira a, b a Departmento de Biologia & Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus Universit ario de Santiago, 3810-193 Aveiro, Portugal b Sociedade Portuguesa de Vida Selvagem, Universidade do Minho, Departamento de Biologia, Campus de Gualtar, 4710-057, Braga, Portugal c Departamento de Biologia & Centro Biologia Molecular e Ambiental (CBMA), Universidade de Minho, Campus de Gualtar, 4710-047 Braga, Portugal d Departament de Biología, Sanitat i Medi ambient, Facultat de Farm acia i Ci encies de l’Alimentaci o, Universitat de Barcelona, Av. Joan XXIII, sn, 08028 Barcelona, Spain e Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Joan XXIII, sn, 08028 Barcelona, Spain f Centro de Estudos do Ambiente e do Mar (CESAM), Campus Universit ario de Santiago, 3810-193 Aveiro, Portugal highlights  High levels of cadmium in loggerheads stranded in mainland Portugal.  Evidence of bioaccumulation of renal cadmium.  Cadmium-Zinc correlations were observed in liver and kidney tissues.  The 3 largest loggerheads showed lower Cd concentrations than smaller turtles. article info Article history: Received 5 January 2017 Received in revised form 13 March 2017 Accepted 26 March 2017 Available online 27 March 2017 Handling Editor: Martine Leermakers Keywords: Bioaccumulation Cadmium Marine turtle Northeast Atlantic abstract Pollution is among the most significant threats that endanger sea turtles worldwide. Waters off the Portuguese mainland are acknowledged as important feeding grounds for juvenile loggerheads. How- ever, there is no data on trace element concentrations in marine turtles occurring in these waters. We present the first assessment of trace element concentrations in loggerhead turtles (Caretta caretta) occurring off the coast of mainland Portugal. Also, we compare our results with those from other areas and discuss parameters that may affect element concentrations. Trace element concentrations (As, Cd, Cu, Pb, Mn, Hg, Ni, Se, Zn) were determined in kidney, liver and muscle samples from 38 loggerheads stranded between 2011 and 2013. As was the only element with higher concentrations in muscle (14.78 mgg 1 ww) than in liver or kidney. Considering non-essential elements, Cd presented the highest concentrations in kidney (34.67 mgg 1 ) and liver (5.03 mgg 1 ). Only a weak positive link was found between renal Cd and turtle size. Inter-elemental correlations were observed in both liver and kidney tissues. Hepatic Hg values (0.30 ± 0.03 mgg 1 ) were higher than values reported in loggerheads in the Canary Islands but lower than in Mediterranean loggerheads. Cd concentrations in the present study were only exceeded by values found in turtles from the Pacific. Although many endogenous and exog- enous parameters related with complex life cycle changes and wide geographic range may influence trace element accumulation, the concentrations of Cd are probably related to the importance of crus- taceans in loggerhead diet in the Portuguese coast. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Along with other large marine vertebrates, marine turtles are known as key animal groups acting as sentinels of environmental disturbances, reflecting natural and anthropogenic threats on a * Corresponding author. Departmento de Biologia & Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus Universit ario de Santiago, 3810-193 Aveiro, Portugal. E-mail address: lvrnicolau@ua.pt (L. Nicolau). Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere http://dx.doi.org/10.1016/j.chemosphere.2017.03.108 0045-6535/© 2017 Elsevier Ltd. All rights reserved. Chemosphere 179 (2017) 120e126