Metallothionein Induction in the Sandhopper Talitrus saltator (Montagu) (Crustacea, Amphipoda)

We investigated metallothionein (MT) induction in the talitrid amphipod Talitrus saltator, a well-established biomonitor of trace metal contamination in the supralittoral environment, in response to laboratory exposure to Hg, Cd, or Cu for 3, 6, 24, and 48 h. Analyses were also carried out on animals collected in the wild from six localities along the Tuscan coast with different degrees of trace metal contamination. Animals exposed to Hg in the laboratory showed a strong dose-dependent increase of MT levels after 3 and 6 h; in the following hours (24 and 48 h), the MT concentrations reached control levels, possibly due to a general toxic effect of Hg. For the other metals, MT induction was observed in animals exposed to 10 ppm of Cd and 5 and 10 ppm of Cu. Therefore, despite the positive correlation between MT concentrations and trace metals in sandhoppers collected in the wild, the fast MT response observed in the laboratory suggests an inappropriate use of MT as biomarkers to assess trace metal pollution in coastal areas.