Distribution of copper in gills of Japanese freshwater crabs Geothelphusa dehaani examined using micro-PIXE analysis

Abstract

In the present study, we examined copper accumulation and distribution in the gills of Japanese freshwater crabs Geothelphusa dehaani exposed to copper chloride, using microbeam scanning particle induced X-ray emission (micro-PIXE) analysis to clarify the potential of this decapod crustacean as an indicator organism for copper pollution. After exposure of the crabs to copper chloride (1mg/L) for 3 days, the copper concentration in the gills was 161±48μg/g of tissue wet weight, which was four times higher than the control value. Copper was found not only on the surface, but also inside the gills, and especially localized at the gill axis. In the morphological examination, severe damage of the gills was not observed in the exposure group, while hemagglutination was detected at the gill axis. The results suggest that the Japanese freshwater crab would be useful as a model organism for understanding mechanisms of toxicity, and that crab gills may be an effective indicator of copper pollution.