Determination of acute toxicity levels of mercury to the fish Tilapia mossambica (Peters)

Abstract

Toxicity of inorganic mercury to the freshwater fish Tilapia mossambica was demonstrated by static bioassays. Statistical analysis was used for calculating 48 hr median tolerance limit, 95% confidence limits and the slope function (S). No mortality was observed within 48 hr in mercuric chloride concentration of 0.7 mgl^-1 although the swimming activity of the fish decreased and the rate of opercular movement increased significantly. Concentrations of 0.9 mgl^-1 and higher proved lethal. Symptoms of mercury poisoning and safe concentrations of mercury have been discussed.