Calibration of the estuarine amphipods, Gammarus zaddachi Sexton (1912), as biomonitors: toxicokinetics of cadmium and possible role of inducible metal-binding proteins in Cd detoxification

Abstract

Collectives of gammarid amphipods ( Gammarus zaddachi and G. salinus) from four localities of the Ems- and Weser-estuary and from the freshwater tidal region of the River Hunte (NW-Germany) were exposed to constant Cd concentrations (51.5 ± 1.3 μg l −1) in artificial sea-water (5 ‰ salinity) for 15 days to investigate bioaccumulation and possible induction of metal-binding proteins in these amphipods. Toxicokinetic parameters (BCFs, rate constants) were calculated, to calibrate these amphipods as biomonitors for Cd. Our toxicokinetic study and additional literature data provide further support to utilize these organisms for biomonitoring, indicating BCFs for Cd within the same dimension (409–576) independent of the Cd exposure conditions, of the species and of the habitats considered. Results of gel and ion exchange chromatography indicate that metallothioneins or metallothionein-like proteins are not likely to play an important role in possible Cd detoxification in G. zaddachi, despite substantial Cd uptake up to 30 mg kg −1 (d.w.). Only a small amount of Cd appeared to be eventually bound to cytosolic components.