ACUTE EXPOSURE OF TRANSCAUCASIAN BARB (CAPOETA CAPOETA CAPOETA) TO NITRITE: DETERMINATION OF MEDIAN LETHAL CONCENTRATION (LC_(50)), GENOTOXIC AND HISTOPATHOLOGIC EFFECTS

摘要

Nitrite is an important environmental pollutant, and is used widely as an additive in foodstuffs. In this study, acute toxic, genotoxic and histopathologic effects of nitrite in Transcaucasian barb (Capoeta capoeta capoeta) were investigated. The median lethal concentration (LC_(50)) at 96 h of exposure was determined to be 122.8 mg L~(-1). In the follow-up study, fish were exposed to 25, 50, 75 and 100 mg L~(-1) of nitrite for 96 h. To determine aneugenic activity, which is characterized by the formation of binu-cleated erythrocytes, blood samples were collected at 36 and 96 h. A dose and time-dependent aneugenic activity was observed in fish. At the end of the exposure period, fish were necropsied and tissue samples were processed routinely for histopathological examination. Degenerations in the renal tubular epithelium, liver hepatocytes, as well as light to mild degenerations in epithelial and chloride cells of the secondary lamella of gills were noted. Increased apoptotic cell death was detected in the hematopoietic region of kidney in nitrite-exposed fish as tested by in situ TTJNEL assay. The results indicate that high levels of nitrite might cause prominent genotoxic and cellular alterations in Capoeta capoeta capoeta.