Rainbow Trout Gills Are a Sensitive Biomarker of Short-Term Exposure to Waterborne Copper

Hepatic copper levels may not indicate short-term exposure to waterborne copper in teleosts. Significantly higher copper loads were found in the gills of rainbow trout exposed to 105 μg · L-1 total measured copper for a period of 24 h than in control animals where no differences were recorded in hepatic copper levels. A second experiment exposing trout to 153 μg · L-1 total measured copper also demonstrated significant differences in branchial copper levels between control and exposed animals after 3 h exposure. The ratio of the copper load in the gills to the liver, and copper/zinc ratios of the gills were also examined. After exposure to 105 μg · L-1 for 24 h both gill/liver copper ratios and Cu/Zn ratios in exposed animals were significantly greater than in control animals. After 12 h exposure to 153 μg · L-1 total measured copper the gill Cu/Zn ratio was significantly greater than in control animals. These data indicate the gills may be a better indicator of short-term exposure than the liver.