Volume No. 4 Issue No.: 3 Page No.: 705-712 Jan.-Mar 2010

 

ACUTE TOXICITY STUDIES ON INDIAN FLYING BARB, Esomus danricus (HAMILTON-BUCHANAN), IN RELATION TO EXPOSURE OF HEAVY METALS, CADMIUM AND COPPER

 

Suchismita Das*1 and Abhik Gupta2

1. Department of Life science, Assam University, Silchar (INDIA)
2. Department of Ecology and Environmental Science, Assam University, Silchar (INDIA)

 

Received on : October 16, 2009

 

ABSTRACT

 

Aquatic organisms are good indicators of environmental pollution because they concentrate pollutants in their tissues directly from water and sediments, and through them, it is also possible to assess the bioaccumulation of pollutants in the food chain. Only biological monitoring can tell us what toxic materials are doing to organisms. The susceptibility of fish to a particular xenobiotic is a very important factor for lethal concentration, LC50 values (concentration that kills 50% of test population). The fish that is highly susceptible to toxicity of one chemical may be less or non-susceptible to the toxicity of another at same concentration of that chemical. The purpose of acute toxicity test is to assess various abnormalities caused due to administration of a chemical to animals and to determine the order of lethality of the chemical. In aquatic toxicology, acute lethal toxicity tests with fish or invertebrates are usually intended to assess the numerical value of toxicity, to compare potencies of toxicants and to assess the effects of environmental variables on toxicity. Fishes are sensitive to external perturbations in aquatic medium. Therefore, it has become imperative to determine whether a potential toxicant is harmful to fish and if so, to find out the relationship between toxicant concentration and its effects on fish. Esomus danricus (Hamilton-Buchanan) is endemic to North India and found in shallow water bodies adjoining paddy and tea cultivation. In the present study, behavioural changes and acute toxicities for two heavy metals Cadmium and Copper were determined. Acute toxicity (LC50) on E. danricus for 24, 48, 72 and 96hrs for Cd were 19254μg/l, 12773.6μg/l, 8432 μg/l and 6363 μg/l respectively. The LC50 values for 24, 48, 72 and 96hrs for Cu were and 1.02μg/l, 0.25μg/l, 0.07μg/l and 0.01μg/l respectively. Copper showed toxic effects at much lower dose than Cadmium. Several behavioural manifestations were also noted for exposure durations.

 

Keywords : LC50, Toxicity, Cadmium, Copper, E. danricus

 

 

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