Pandey Rakesh K, Singh Ram N, Singh Sarika, Singh Narendra N, Das Vijai K
Department of Zoology, Kamla Nehru Institute of Physical and Social Sciences, Sultanpur, India.
J Environ Biol. 2009 May;30(3):437-40.
Pesticides are chemicals used for pest control in the agricultural fields. They finally reach the surrounding water bodies through surface runoff affecting the aquatic fauna. Dimethoate is frequently used organophosphate pesticide due to its high effectiveness and rapid breakdown into environmentally safe products. A 96 hr static acute toxicity test was carried out to determine the LC50 value of dimethoate, on the freshwater airbreathing catfish Heteropneustes fossilis (Bloch). The fish were exposed to 7 different concentrations of dimethoate (2.50, 2.75, 3.00, 3.25, 3.50, 3.75 and 4.00 mg l(-1)) for toxicity bioassay. Control (0.00 mg l(-1)) was also carried out. The data were subjected to Finney's Probit analysis and processed with Trimmed Spearman-Karber statistical software. The LC50 values for dimethoate for 24, 48, 72 and 96 hr were 3.38, 3.23, 3.08 and 2.98 mg l(-1), respectively. At higher concentration of dimethoate (3.25 mg l(-1) and above) the fish showed uncoordinated behaviour such as erratic and jerky swimming, attempt to jump out of water, frequent surfacing and gulping of air, decrease in opercular movement and copious secretion of mucus all over the body.
农药是用于农田害虫防治的化学物质。它们最终通过地表径流进入周围水体，影响水生动物。乐果是一种常用的有机磷农药，因其高效且能迅速分解为对环境安全的产物。进行了一项96小时的静态急性毒性试验，以测定乐果对淡水呼吸鲶鱼印度胡鲶（Bloch）的半数致死浓度（LC50）值。将鱼暴露于7种不同浓度的乐果（2.50、2.75、3.00、3.25、3.50、3.75和4.00毫克/升）进行毒性生物测定。同时也设置了对照组（0.00毫克/升）。数据进行了芬尼概率分析，并使用截尾斯皮尔曼-卡尔伯统计软件进行处理。乐果在24、48、72和96小时的LC50值分别为3.38、3.23、3.08和2.98毫克/升。在较高浓度的乐果（3.25毫克/升及以上）下，鱼表现出不协调的行为，如游动不稳定、急促跳动、试图跳出水面、频繁浮出水面和大口呼吸空气、鳃盖运动减少以及全身大量分泌黏液。
