Title: 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, wereinvestigated through semi-static acute toxicity test developed with mercury chloride (HgCl2). ). Fingerlings (2.76±0.21 cm and 0.51±0.12 g) were kept during 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 0.220 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. [Hussein A. Kaoud and Mohey M. Mekawy (2011). Bioremediation the Toxic Effects of Mercury-Exposure in Nile Tilapia (Oreochromis Niloticus) by using Lemna gibba L. Journal of American Science 2011;7(3):336-343].