Metallothionein as bioindicator of freshwater metal pollution: European eel and brown trout

The aim of this work was to evaluate the potential of metallothionein (MT) as a bioindicator of heavy metal pollution in brown trout and European eel in the field situation. River Ferrerias (North Spain) provided a good gradient of metal contamination: concentrations of heavy metals were elevated both in water and in sediments at the downstream (polluted) site and were low at the upstream (unpolluted) site. MT levels of brown trout exhibited statistically significant differences between sites. Although European eel at the polluted site had a higher MT content, differences were not significant. It is concluded that MT is a good bioindicator of heavy metal pollution in brown trout.