Pranali S. Shirsat and Vinod R. Ragade
Abstract
Lead (Pb) is a bioaccumulating contaminant (pollutant) that enters aquatic systems and causes behavioral, physiological and mortal effects on freshwater fish species. The current study determined the median lethal concentration for Oreochromis mossambicus due to the acute toxicity of lead acetate over a 96-hr lethality assay in accordance with OECD regulations. Mortality was documented at 24-hour intervals and analysed through Probit analysis to estimate the LC50 value. The 96-hr LC50 value was 17.21 mg L-1 with 95% confidence interval of 8.21-36.02 mg L-1. Fish were observed for alterations in behavior and response showed opercular movement, loss of equilibrium, erratic swimming, excessive secretions of mucous, and gulping at the surface. Water quality parameters such as temperature, pH, dissolved oxygen, hardness, conductivity, and alkalinity, determined during the course of study confirmed that the experimental conditions were acceptable and corrected for variability in toxic effect. The study provides a detailed profile of acute lead toxicity, integrating LC50 estimation, behavioral biomonitoring, and physicochemical water quality evaluation; and establishes baseline data for further chronic and histopathological studies.