Toxicological Effects of Copper on Behavior, Neuroanatomy, and Neurophysiology of Salmon

Salmon behavior, olfactory structure, and olfactory function were impaired by exposure to copper in soft water (hardness and alkalinity of 25 mg/L).  Salmon behavior was measured as behavioral avoidance of copper. Olfactory structure was measured by counting olfactory receptor neurons after exposures to copper. Olfactory function was measured by electroencephalogram response to L-serine stimulation after the olfactory rosette was exposed to copper. Responses were different between Chinook salmon and rainbow trout, with Chinook salmon being more sensitive. Both species avoided low concentrations of copper, but Chinook salmon did not avoid concentrations greater than 44 µg/L, and rainbow trout did not avoid concentrations greater than 180 µg/L. A one-hour exposure to similar copper concentrations caused significant loss of olfactory neurons and significant reduction in olfactory response to L-serine.