Hepatic levels of metal and metallothioneins in two commercial fish species of the Northern Iberian shelf

Metal levels (Cd, Pb, Hg, Cr, Fe, Cu, Zn) together with metallothioneins (MTs) were determined in the liver of two commercial fish species collected along the Northern Iberian coast. The four-spotted megrim (Lepidorhumbos boscii) and the pouting (Trisopterus luscus) were selected as representative species of the middle/outer (200–500 m) and inner shelf (70–120 m), respectively. Metal pollution in the middle/outer shelf was mostly detected in the Asturias and Basque Country areas, whereas in the inner shelf, pollution was widely spread along the coast. Significantly high levels of Pb, Cd, Cr and Hg were detected in T. luscus from different sampling sites and associated to anthropogenic pressure. MTs were induced in fish that had higher amounts of Zn, Cd, Cr and Hg in their livers, supporting the use of MT as a biomarker of metal exposure. The study supports the usefulness of the selected fish species as sentinel organisms for future biomonitoring studies.