Effects of gallium on common carp (Cyprinus carpio): acute test, serum biochemistry, and erythrocyte morphology

Gallium (Ga) is one of the intermetallic elements that are increasingly being used in making high-speed semiconductors such as gallium arsenide. The purposes of this study were to investigate the effects of gallium on acute toxicity, on serum biochemical variables as well as on erythrocyte morphological changes in the blood stream of common carp (Cyprinus carpio). Median lethal concentrations were determined in acute tests. The 96-h LC50 value was 19.78 (18.49-21.16) mgl(-1). Common carp were exposed to different gallium concentrations (2.0, 4.0, and 8.0 mgl(-1)) for 28 days in laboratory toxicity tests. Means of the measured serum biochemistry parameters (including glucose, blood urea nitrogen, creatinine, cholesterol, and triglyceride) of these exposed groups significantly differed from those of the untreated group. Deformation of erythrocytes suggest disturbance of respiration as an additional indicator of Ga exposure. Our results suggest that 2.0 mgl(-1) is proposed as a biologically safe concentration which can be used for establishing tentative water quality criteria concerning of same size common carp. In addition, serum biochemical parameters as well as erythrocyte morphological changes are promising clinical diagnostic tools for assessing the effects of gallium compounds on common carp.