Effects of some heavy metals on toxicity of the fresh water fish: Rasbora daniconius
Jagdish V Jagatkar
Heavy metals pose a great threat to aquatic organism not only because they are highly toxic in low quantity but also because of their potential characteristic of combining with biological moleculs. Metals like mercury, cadmium and lead all show a great affinity for sulfhydryl (-SH) groups and exert toxic effects largely by combining with such groups on proteins. One of the most significant effect of metallic pollution is that aquatic organisms can adsorb and accumulate concentrations in their tissues. For example, there may be up to 15 times as much mercury present in fish. The LC10 and LC50 values for heavy metals were summarized in (Table 1 & 2).The LC10 of lead acetate for 24, 48, 72, and 96 hours were 3.34,3.80, 1.99 and 1.90 ppm respectively. The LC10 of zinc sulphate for 24, 48, 72 and 96 hours were 6.64, 5.71, 2.99 and 1.99 ppm respectively. The LC10 of nickel chloride for 24, 48, 72 and 96 hours were61.07, 18.63, 23.09 and 9.29 ppm respectively. The LC50 of zinc sulphate for 24, 48, 72 and 96 hrs were 14.6, 12.65, 9.38 and 6.26 ppm respectively and LC50 of nickel chloride for 24, 48, 72 and 96 hrs were 82.78, 69.15, 44.86 and 29.22 ppm respectively. Where as in preset study no such behavioral changes were noticed in the control fish, which remained active and healthy throughout the experimental period.