Nonuniform accumulation of cadmium and copper in kidneys of wild brown trout (Salmo trutta) populations.

Cadmium and copper accumulated nonuniformly in the kidney of wild brown trout on a longitudinal gradient as follows: the concentration in head kidney < anterior portion of tail kidney < posterior portion(s) of tail kidney. Zinc accumulated uniformly along the length of the kidney. Cadmium and copper accumulation in brown trout kidneys was lowest in the head kidney, where hematopoietic tissue dominates, and greatest in posterior tail sections, where filtration tissues dominate. Sampling programs designed to monitor cadmium and copper accumulation in trout kidneys should utilize the entire kidney, including the head kidney, to create comparable data sets.