Mortality, bioaccumulation and physiological responses in juvenile freshwater mussels (Lampsilis siliquoidea) chronically exposed to copper

► Chronic toxicity and physiological effects of copper were evaluated in fatmucket. ► Toxicity was not associated with copper bioaccumulation in soft tissues. ► Freshwater mussel is marginally protected by current WQC for copper. ► Chronic copper toxicity is associated with whole-body ionoregulatory disturbances. ► Pre-exposure to copper did not influence mussel response to a copper challenge test.