Toxicity of selected organic pesticides to a fresh water teleost fish,Saccobranchus fossilis and its application in controlling water pollution

Abstract

Bioassay studies have been conducted with chlordane (an organochlorine compound), and Ekatin®, Ekalaux®, and Sumithion® (organophosphorous compounds) to determine the LC₅₀, acute toxicities, relative toxicities, presumable harmless concentrations, and dilution volumes for a period of 24-, 48-, 72-, and 96-hr to a fresh water teleostSaccobranchus fossilis. The 24-, 48-, 72-, and 96-hr LC₅₀ for chlordane, Ekalaux, Ekatin, and Sumithion are 0.54, 0.49, 0.46, and 0.42 mg/L; 2.75, 2.40, 1.75, and 1.55 mg/L; 12.40, 12.10, 11.75, and 11.00 mg/L; and 14.90, 14.20, 13.75, and 12.50 mg/L, respectively. Presumable harmless concentrations are 0.12, 0.55, 3.46, and 3.87 mg/L, respectively, which are a fraction of LC₅₀ values. The relative toxicities of these pesticides calculated on the basis of 24-hr LC₅₀ to the fish are 27.59, 5.42, 1.20, and 1.00 for chlordane, Ekalaux, Ekatin, and Sumithion, respectively. The acute toxicity for Sumithion to the test fish lies between 12.10 and 18.75 mg/L, for chlordane between 0.37 and 0.75 mg/L, for Ekatin between 10.00 and 14.20 mg/L, and for Ekalaux between 1.35 and 3.25 mg/L. It is concluded from the study that chlordane is the most toxic and Sumithion is the least toxic while the toxicities of Ekatin and Ekalaux lie between the two. When the data for survival of the test fishvs. log concentration are plotted, they exhibit a linear relationship following the formula Y= ¯Y+b(X−¯X). The presumable harmless concentrations can be utilized on broad lines for controlling short-term water pollution by these pesticides.