After exposure, the fish were rinsed in 10 l of metal-free experimental water for 30 min to remove surface-bound metal before being killed. The water was changed after 5 min of rinsing. This procedure has previously been shown to remove all detectable surface-bound Cd from the gills, without any detectable loss of intracellular Cd in the gill epithelium. The water temperature and the photoperiod were the same as during acclimation and the fish were not fed.