Total metal burdens in the freshwater amphipod Gammarus fasciatus: Contribution of various body parts and influence of gut contents

1. The distribution of trace metals among body parts of the freshwater amphipod Gammarus fasciatus was investigated and the effect of depuration on the total body burden was assessed. 2. Concentrations of Cr, Fe, Mn and Ni were one order of magnitude higher in the gut contents than in the various body parts, accounting for 40-72% of the total body burdens of amphipods. Depuration caused a decrease of total metal concentrations of 35-88%. 3. Levels of Cd and Cu were higher in the hepatopancreas than in other body parts, whereas levels of Zn were relatively constant throughout the body. For Cd, Cu and Zn, depuration had no effect on mean body concentrations. 4. For Pb, an important fraction of the total body burden was associated with the exoskeleton; depuration caused a decrease in Pb body concentrations. 5. Regression between amphipod metal concentrations before and after depuration is a potential tool for correcting for the effect of gut contents. This correcting method was found to be promising for Cd, Cu, Mn and Zn, with R(2) varying between 0.66 and 0.98. It was less efficient for Cr, Fe and Pb, and was useless for Ni.