Table 1: Values of the organ damage index* (ODI) calculated for the liver and kidney of zeabra-seabreams exposed to the different treatments. No lesions were observed in control fishes. MeHg: exposure to Methylmercury; HgII: exposure to Hg2+; MeHgSe: coexposure to MeHg and Se; HgSe: coexposure to Hg2+ and Se; MeHgRSe: exposure to MeHg followed by exposure to Se during depuration; HgRSe: exposure to Hg2+ followed by exposure to Se during depuration; Se: exposure to selenium.

Organ lesion (OL) Pi MeHg HgII MeHgSe HgSe MeHgRSe HgRSe Se d28 d42 d28 d42 d28 d42 d28 d42 d42 d42 d28 d42 Liver Architectural pattern lost 1 4 3 4 4 3 2 4 0 3 3 2 0 Vacuolar degeneration 1 3 1 4 1 2 0 1 2 3 3 2 0 Hydropic degeneration 1 4 2 3 1 1 2 1 1 0 3 0 0 Hypertrophy of hepatocytes 2 2 3 1 4 4 0 4 1 0 0 0 0 Extensive focal necrosis 3 0 3 2 4 0 2 1 3 0 2 0 0 Focal necrosis 2 3 0 0 0 1 2 2 0 3 1 0 0 Parenchymal congestion 1 0 1 2 0 1 0 3 0 0 0 0 0 Pigment deposition 1 0 0 2 0 0 0 0 0 0 0 0 0 ODI 21 22 23 26 17 14 24 14 12 17 4 0 Kidney Vacuolar degeneration 1 1 0 1 2 1 1 0 1 1 2 0 0 Hydropic degeneration 1 3 2 1 0 1 3 0 3 0 2 0 0 Pigment deposition 1 3 1 1 1 0 2 0 1 1 0 0 0 Parenchymal necrosis 3 0 0 0 3 0 0 1 0 0 0 0 0 ODI 7 3 3 12 2 6 3 5 2 4 0 0

Pi: Pathological index of each lesion according to their importance to organ function [38]. : number of fishes displaying one type of organ lesion (OL). *ODI: sum of lesions observed for each organ taking into account their relative severity and the number of fishes ().