Shahla Nigar¹, Neelima Gupta^{1, 2,}, Abha Trivedi¹, Varsha Gupta³

Heavy metal pollution in aquatic bodies has become a matter of great concern. This study examined the acute toxicity of lead nitrate to the freshwater fishes Channa punctatus and Heteropneustes fossilis. They comprise an important link in the food chain, and defilement by heavy metal produces an imbalance in the aquatic environment and other fauna. The fishes were exposed to different concentrations of lead nitrate, and % mortality was recorded during 24, 48, 72, and 96 hours. The lethal concentration (LC50) value of lead nitrate for 96 hours against C. punctatus and H. fossilis were found 158.171 and 280.074 mg/l, respectively, using the Probit analysis statistical method. The mortality of the fish was directly proportional to the concentration. The results indicated that a lower concentration of lead was highly toxic to C. punctatus than H. fossilis. Assessment of LC50 also revealed that the amount of lead present in freshwater might be lethal to all the aquatic fauna. Exposure to lead affected human health, which accounted for the death of 1.06 million people and loss of healthy life, amounting to nearly 24.4 million. Hence, strict regulations should be imposed to dispose of heavy metals in aquatic bodies to conserve valuable biological diversity.

lead nitrate, Channa punctatus, Heteropneustes fossilis, LC₅₀, probit