Oxidative stress responses in Puntius sarana collected from some environmentally contaminated areas of River Mahananda, Malda, West Bengal.

Environmental contaminant-induced aquatic pollution threatens the aquatic biota and causes oxidative stress in the aquatic organisms. Mahananda River, the lifeline of Malda district, West Bengal, India is presently experiencing environmental crisis due to increasing level of contaminants which deteriorate the water quality along with its biota. Puntius sarana is an economically important edible fish species in the River Mahananda that seems to be declining, owing to environmental pollution. Therefore, the present study aimed to investigate the health status of Puntius sarana by evaluating different oxidative stress biomarkers. The sampling sites were selected according to population density and possible anthropogenic activities around the River Mahananda. Significantly higher concentration of Zn (p < 0.01), Cu (p < 0.05) in different sampling sites has been observed, compared to the control site. Results of the water quality index and water pollution index confirmed the pollution status of different sampling sites. Significant decreases were observed in superoxide dismutase and catalase activity, compared to the control. The decreased values of reduced and oxidized glutathione ratio also indicate the increased oxidative stress of Puntius sarana. The principal component analysis showed that total hardness, calcium hardness, nitrate, manganese, zinc, copper, iron and arsenic were the main descriptors of the aquatic pollution. Therefore, findings of the present study demonstrate the ecotoxicological impacts of various anthropogenic activities which necessitates the need for continuous monitoring of the fresh water resources and its ecosystem from further contamination.