Tissue-specific mercury concentrations in two catfish species from the Brazilian coast

Some regions of Brazil have particularly high levels of mercury (Hg) emissions due to industrial activities, and their fish species may therefore suffer high levels of contamination through bioaccumulation. In this paper we assess Hg contamination in the muscle, liver, gills and blood of two different species of catfish collected from the Cananéia and Santos-São Vicente estuaries, São Paulo State, Brazil. Fish from the most polluted site (Santos-São Vicente) showed higher median Hg concentrations in both species (Cathorops spixii - liver: 1530 µg Kg-1, muscle: 327 µg Kg-1 and gill: 101 µg Kg-1; Genidens genidens - liver: 2617 µg Kg-1, muscle: 393 µg Kg-1 and gill: 118 µg Kg-1). Multivariate analysis revealed the importance and influence of key biological variables (size, condition, etc.) in determining the overall level of Hg and its distribution within different tissues