Chromium (VI) induced acute toxicity and genotoxicity in freshwater stinging catfish, Heteropneustes fossilis

Acute toxicity and genotoxicity of Chromium(VI) as K2Cr2O7 were evaluated in freshwater stinging catfish, Heteropneustes fossilis. Fish showed behavioral alterations after K2Cr2O7 exposure and 96 h-LC50 was 35.724 mg/L in semi-static bioassay. Fish were exposed to three sub-lethal concentrations (concentration I=1/4th of 96 h-LC50, concentration II=1/10th of 96 h-LC50 and concentration III=environmental concentration of Cr reported in the river Buriganga). Blood, liver and gill samples were collected after 48 h, 96 h and 192 h. Micronucleus (MN) assay was conducted in blood erythrocytes and DNA damage was evaluated by comet assay in whole blood, gill and liver tissues. Cr(VI) significantly (p<0.05) induced MN frequency and tail DNA (percent) which increased in a concentration depended manner in all types of tissues. Frequency of MN and tail DNA (percent) increased after 48 and 96 h of exposure which decreased after 192 h of exposure. The liver was the most sensitive to chromium (VI) exposure among the tissues with highest tail DNA (33.70±0.68 percent) at 9.0 mg/L after 96 h. This study found MN and comet assays in combination as an adequate approach for ecotoxicological monitoring and Cr(VI) as potential genotoxic agent.

► Chromium (VI) induced acute toxicity and genotoxicity to Heteropneustes fossilis.
► DNA damage and micronucleus frequency increased with increasing concentration.
► Toxic effect increased with exposure duration.
► Liver experienced greater DNA damage than gill and blood cells.