Tissue-specific Cu bioaccumulation patterns and differences in sensitivity to waterborne Cu in three freshwater fish:: rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio), and gibel carp (Carassius auratus gibelio)

Rainbow trout (Oncorhynchus mykiss), common carp (Cyprinus carpio) and gibel carp (Carassius auratus gibelio) were exposed to copper (1-20 muM) in softened Antwerp City tap water at pH 7.3 +/- 0.1 and with a water hardness of 292.4 +/- 18.1 mg/L CaCO3 (Ca 100.8 +/- 3.0mg/L; Mg 11.0 +/- 0.2mg/L). LC50s (96h) were determined and copper accumulation in gills, liver, and kidney assessed over a 10-day period. Rainbow trout (96 h LC50: 3.3 muM/210 mug/Q were three times more sensitive to Cu exposure than common carp (96 h LC50: 10.4 muM/661 mug/L) and almost seven times more sensitive than gibel carp (96 h LC50: 22.0 muM/1398 mug/L). After 96 It, the incipient lethal level (ILL) was reached for common carp, and by the end of the experiment (> 120 h) also for rainbow trout. The ILL was never reached for gibel carp. Survival analysis confirmed the differences in sensitivity shown by the 96h LC50 values. At 1 muM Cu, the relative risk to die was six to seven times greater for rainbow trout as for common or gibel carp, respectively, while it was 9000 and 19,000 times greater at 5 muM Cu. Only the environmental Cu concentrations contributed significantly (P < 0.001) to the Time-To-Death (TTD). Tissue Cu concentrations did not relate to TTD. Among species, a clear difference in metal handling was apparent, with high liver residues and liver accumulation rates for the most sensitive species, the rainbow trout, and lower liver but higher kidney residues and kidney accumulation rates for the most resistant species, the gibel carp. Gill concentrations and accumulation rates were lowest in the sensitive rainbow trout. (C) 2004 Published by Elsevier B.V.