No abstract

The acute toxicity, in terms of 96-hr LC50 and lethal concentration, of aluminum (Al) regarding four fish species viz. Labeo rohita, Cirrhina mrigala, Catla catla and Ctenopharyngodon idella of 90-, 120-and 150-day age groups was determined under the wet laboratory under static bioassay. All the tests were performed, separately, at constant water temperature (30°C), pH (7.5) and hardness (300mgL-1). All fish species showed significantly (p<0.05) variable sensitivity to different concentrations of aluminum. However, Labeo rohita of all the three age groups showed significantly least sensitivity, in-terms of 96-hr LC50 and lethal concentration, against aluminum. For the age groups, 90-day fish showed significantly higher sensitivity, followed by that of 120-and 150-day old fish groups. Among fish species, Ctenopharyngodon idella exhibited significantly (P<0.05) higher sensitivity to aluminum with the mean 96-hr LC50 and lethal concentrations of 56.91±22.17 and 85.66±23.33mgL‾ 1 , respectively while Labeo rohita were significantly least sensitive with the mean 96-hr LC50 and lethal concentrations of 75.50±21.09 and 118.71±23.00mgL‾ 1 , respectively. Physico-chemical variables viz., dissolved oxygen showed highly significant and inverse relationship with aluminum concentration while ammonia had highly significant but positive impact on aluminum concentration of the test media.