EFFECTS OF SALINITY AND pH ON ACUTE TOXICITY OF DIMETHOATE TO PUNTIUS TICTO

Acute toxicity tests were carried out to estimate the LCso values of dimethoate to the freshwater teleost, Puntius ticto. The LCso values were obtained for 24, 48, 72 and 96 hr exposures are 6,839, 5,555, 5.070 and 5.012 ppm at normal laboratory conditions. Observations have been made whether the LCso values were affected by the environmental factors i.e pH and salinity. These environmental factors play an important role in the toxicity of pesticides in fish. The mortality rate during acute toxicity test to different salinity and pH were recorded. The pH result shows that toxicity of dimethoate increases with decrease in pH where as toxicity of dimethoate increases with salinity.