Bioremediation the toxic effects of mercury-exposure in Nile tilapia (Oreochromis niloticus) by using Lemna gibba L.

Abstract

The effect of mercury (Hg) toxicity, its impact on histopathological changes, the median lethal concentration (LC50-96 h) and the bioremediation effect of Lemna gibba L to Nile tilapia, Oreochromis niloticus, were investigated through semi -static acute toxicity test developed with mercury chloride (HgCl 2). ). Fingerlings (2.76±0.21 cm and 0.51±0.12 g) were kept durin g 96 hours in 5-liter glass aquaria, according to the following mercury concentrations, set up in three replicates: 0.00 (control), 0.037 , 0.185 , 0.370 , 0.740 , 0.925 mg Hg L -1 . The value of LC50-96h was estimated in 0.240 mg Hg L - 1 . This study indicated that:1) Hg poisoning caused structural damage in the fish organs ,2) Lemna gibba L (weed and extract) were effective in removing Hg from water and reducing Hg bioaccumulation in liver and muscular tissues of fish , 3) The addition of Lemna gibba L-extract reduced significantly (P<0.05 ) the Hg level uptake as compared to fish exposed to Hg alone and 4) Addition of Lemna gibba L remediated the toxic effect of Hg and provided protection against the degenerative action of Hg. (Oreochromis Niloticus) by using Lemna gibba L. Journal of American Science 2011;7(3):336-343). (ISSN: 1545-1003). http://www.americanscience.org.