Physiology, physicochemistry and metal uptake—A crustacean perspective

The uptake of dissolved trace metals, such as zinc and cadmium, by crustaceans can often be explained in terms of physicochemical changes beyond the physiological control of the crustacean itself. Thus, uptake rates increase with dissolved metal concentration of exposure. Furthermore, at a given metal concentration, changes in uptake rates of zinc and cadmium can typically be explained by changes in the concentration (availability) of the hydrated free metal ion, for example as affected physicochemically by salinity change or the presence of metal-chelating agents. Nevertheless, some crustaceans appear able to counteract to varying degrees such physicochemical effects by what appear to be physiological responses, for example, to low salinity. Such responses vary interspecifically, and cast light on the mechanisms of trace metal uptake by crustaceans.