The Toxicity of Pesticides on the Growth of Fish Medaka Oryzias latipes

Abstract

The purpose of this study was to evaluate the acute toxicity of pesticides including DDT, endosulfan, lindane and atrazine to Medaka Oryzias latipes fish embryos by identify the LC50 value and ratio of mortality after 24, 48, 72, and 96 hours of exposure. The fish O. latipes was obtained from the Biotechnology Center of Ho Chi Minh City, Vietnam, raised, and allowed sexual fertilization to conduct embryo collection. The one-day old fish embryos is harvested and exposed to different concentrations of DDT, endosulfan, lindane and atrazine respectively: 1,300; 1,500; 1,700; 1,900; 2,100 and 2,300 µg.L-1 DDT; 0.01; 0.1; 1 and 10 µg.L-1 endosulfan; 0; 80; 110; 130; 150; 170; 210; 250, and 300 µg.L-1 lindane and 150; 250; 350, and 450 µg.L-1 atrazine. The results showed that endosulfan had the highest toxicity in the four surveying groups, starting at concentration of <1 μg.L-1 (0.6 μg.L-1). The study also noted that four kinds of pesticides caused serious effects on fish embryo growth and survival. Their toxicity gradually decreased from endosulfan to lindane, atrazine and eventually DDT with LC50 values after 96 hours of exposure were 1123.8; 0.6; 116.2 and 165.2 μg.L-1, respectively. The differences between the LC50 values depended on several factors, such as the toxicant concentration, the exposure time... The mortality rates of Medaka embryo O. latipes linearly increased with the toxicant concentrations and the exposure duration. These pesticides inhibited growth leading to the fish embryo death.