Evaluation of Acute Toxicity of Metals Mixture and Bioaccumulation in Freshwater Fish

Abstract

A study was carried out to investigate acute toxicity (96-hr LC 50 and lethal concentrations) of waterborne metal mixture (Fe+Ni) for the fish, Catla catla , Labeo rohita , Cirrhina mrigala , Ctenopharyngodon idella and Hypophthalmichthys molitrix . The degree of bioaccumulation of metals in fish body organs viz. gills, liver, kidney, fins, bones, muscle and skin at both 96-hr LC 50 and lethal concentrations were also determined. Mortality upon the 90-day old fish species was used as a criterion of toxicity during these experiments. With three replications for each test dose, the tests were performed, separately, at constant temperature (30℃), pH (7) and hardness (200 mg/L) of water. Against metals mixture (Fe+Ni), the overall sensitivity of five fish species, determined in terms of LC 50 and lethal concentrations varied significantly. Regarding overall sensitivity of five fish species, Hypophthalmichthys molitrix were significantly more sensitive to metals mixture, followed by that of Labeo rohita , Ctenopharyngodon idella , Catla catla and Cirrhina mrigala . The concentration of both metals in fish body organs were determined by using Atomic Absorption spectrophotometer. Fish kidney exhibited significantly higher ability to amass both these metals during acute exposure of metal mixture. Accumulation of the metals in fish body followed the general order: kidney>liver>skin>gills>fins>muscles>bones. During both 96-hr LC 50 and lethal concentrations fish showed significantly higher accumulation of iron than that of nickel in their body.