Trace-elements, methylmercury and metallothionein levels in Magellanic penguin (Spheniscus magellanicus) found stranded on the Southern Brazilian coast

Highlights: • Feather Cd and Se were lower in comparison with concentrations in soft tissues. • Se mediates the detoxification of Cd, Pb, Hg_inorg and MeHg in penguin liver. • Hepatic metallothionein mediated the detoxification of Cd, Pb and Hg_inorg. • Hepatic MeHg corresponds to the smallest fraction of total Hg in the seabird's liver. • The highest total Hg fraction in liver was present as Hg_inorg. - Abstract: Magellanic penguins have been reported as good biomonitors for several types of pollutants, including trace-elements. In this context, selenium (Se), total mercury, methylmercury, inorganic mercury (Hg_inorg), cadmium (Cd) and lead (Pb), as well as metallothionein (MT) levels, were evaluated in the feathers, liver and kidney of juvenile Magellanic penguins found stranded along the coast of Southern Brazil. The highest concentrations of all trace-elements and methylmercury were found in internal organs. Concentrations of Cd and Se in feathers were extremely low in comparison with their concentrations in soft tissues. The results showed that both Se and MT are involved in the detoxification of trace-elements (Cd, Pb and Hg_inorg) since statistically significant relationships were found in liver. Conversely, hepatic Se was shown to be the only detoxifying agent for methylmercury