Toxicity of selenium on the freshwater tropical worm, Branchiura sowerbyi beddard, 1892 Dhara Kishore, Saha Shubhajit1, Saha Nimai Chandra2 Office of the Deputy Director of Fisheries, Government of West Bengal, 9A, Esplanade East, Kolkata, 700 069, West Bengal, India 1Department of Zoology, Sundarban Hazi Desarat College, South 24 Parganas, 743611, West Bengal, India 2Fisheries Ecotoxicology Research Laboratory (Vice-Chancellor's Research Group), Department of Zoology, University of Burdwan, Golapbagh, Bardhhaman, 713 104, West Bengal, India Online published on 20 July, 2020. Abstract The toxicity of selenium, in the form of sodium selenite, on freshwater tropical worm, Branchiura sowerbyi Beddard, 1892 (Oligochaeta: Naididae: Rhyacodrilinae) was studied. The LC50 values of selenium at 24, 48, 72 and 96h were recorded as 7.086, 4.128, 3.117 and 2.180 mg/l respectively. The mortality of the worm significantly increased (p<0.05) with increasing concentrations of selenium and time of exposure. The toxicity at different time scale and safe levels of selenium to the worm were estimated, in order to generate base line data that could be used to set up water quality criteria (WQC) for the toxicant. The study further focussed on the growth of B. sowerbyi exposed under chronic dose of the toxicant (5 and 10% LC50). The worm showed significant reduction (p<0.05) in growth, measured in the form of dry weight under the influence of chronic doses of the toxicant. The findings will be useful to assess ecological risk for the worm to selenium toxicity. Top Keywords Branchiura sowerbyi, selenium, toxicity, toxicity factor, safe level, growth. Top |