Labeo rohita, a bioindicator for water quality and associated biomarkers of heavy metal toxicity

Abstract

This study investigated the effect of heavy metals on Labeo rohita inhabiting the Yamuna River, India. Levels of heavy metals measured in the water were as follows: Fe>Mn>Zn>Cu>Ni>Cr>Cd. Gill and liver tissue of exposed L. rohita showed a high metal pollution index, compared to reference fish collected from the Agra Canal. In the exposed fish, higher levels of creatinine and enzyme activity (alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase) were observed, while the A:G index declined. Additionally, higher TLC, lymphocytes, respiratory burst, and nitric oxide synthase activity indicated a heightened immune response. Levels of superoxide dismutase and lipid peroxidation were elevated, while catalase, glutathione S transferase, and glutathione was reduced. DNA of the exposed fish appeared deteriorated, with a greater mean tail length in comparison to the reference. Our results imply that Yamuna River water generates oxidative stress and DNA damage in L. rohita. As this river is a critical source of water and food to the native community, this could pose a threat to public health similar to that in the indicator organism.