In the present study, the risk to humans by consuming European sea bass (Dicentrarchus labrax), captured at three sites along a Hg contamination gradient, was evaluated by comparing muscle and kidney total Hg (T-Hg) levels with the European regulations for marketed fish. Moreover, T-Hg and organic Hg (O-Hg) levels in muscle were compared with the Provisional Tolerable Weekly Intake (PTWI) and the Reference Dose (RfD). Although T-Hg levels in muscle were below the European value allowable for marketed fish, kidney’s levels were higher than the set value, stressing the importance of redefining the concept of edible tissue and which tissues should be considered. Mercury weekly ingestion in the contaminated areas was higher than the PTWI, and O-Hg daily ingestion rates were higher than the RfD in all sampling sites. Thus, populations consuming sea bass from the contaminated sites may be at risk, with particular relevance for children and pregnant women.

The effluents from bleached Kraft pulp mill (BKME) and paper industry are toxic to different aquatic organisms being an important source of contamination to aquatic environments due to the presence of several chemicals produced during the production of Kraft pulp. The main objective of the present study was to evaluate the exposure effects of a secondary-treated BKME in two different species of fish: Carassius auratus and Dicentrarchus labrax. Both species were exposed to different concentrations of secondary-treated effluent (1%, 10%, 25%, 50%, 100%) in semi-static tests under controlled laboratory conditions. At the end of the experimental period (21 days), samples of livers were collected for CYP1A determination and histopathological evaluation. The results show significant changes (p < 0.05) of CYP1A induction in carp exposed to 50% and in sea bass exposed to 25% of the effluent. Histopathological alterations were also observed according to the different concentrations of the tested effluent suggesting that tested BKME cause damage to exposed organisms.