Metal exposure assessment in native fish, Mullus barbatus L., from the Eastern Adriatic sea

Metallothionein (NIT) and metal (Zn, Cu, Fe, Mn, Cd) association in the cytosol of liver, kidney and intestine was studied on native Mullus barbatus specimens. Investigated parameters of all specimens (1 to 8-year-old) were related to the fish length, which reflects fish growth and aging. Cytosolic metal concentrations in liver, kidney and intestine are tissue specific but in general decrease as follows: Fe approximate to Zn > Cu > Mn > Cd. Metallothionein levels are also tissue specific with the highest level in intestine, followed by kidney and liver. Percentage partition of NIT and Zn in liver, kidney and intestine cytosol of red mullet is comparable. Associations of NIT and metals that induce NIT synthesis exist in liver for MT/Zn (r=0.28) and MT/Cu (r=0.26) and in intestine for MT/Cu (r=0.38). Unlike essential metals, there is no significant correlation between NIT and the toxic metal Cd, what is ascribed to its very low cytosolic concentration. The most pronounced size-related accumulation is found for the toxic metal Cd in liver cytosol (r=0.69), indicating chronic Cd accumulation. Negative correlation between metals (Cd, Zn, Fe, Mn) and the condition factor also indicates chronic metal effects and their metabolic impact. (c) 2006 Elsevier Ireland Ltd. All rights reserved.