Study of Hg effects on liver tissue in Rutilus rutilus of Caspian sea in vitro

A series of specific toxicological effects including bioaccumulation of the pollutant، histological changes and influences on liver tissue were examined in the Roach fish (Rutilus rutilus) after the exposure to graded sublethal concentrations (10، 30، 50 μg Hg/L) of mercury chloride (MC). Histopathological changes، such as oedema، vacuolization، pyknotic nucleus، telangiectasis، and degenerative، can clearly be observed in the slices from the liver exposed Roach. A batch of Roach with the mean values of 5 cm in length and 5. 5 g in mass were pre-raised in a static system، which was supplied with dechlorinated tap water and constantly aerated. The water qualities were controlled as follows: pH، 7. 45; oxygen concentration، 7 mg/L; the water temperature، 21–22 ◦C. All fish were fed twice a day with a commercial ration of biomar. Reagents Appropriate amount of mercury chloride (MC، AR 98%، Merck-Schuchardt) was dissolved in a stock solution of 0. 676g HgCl2/L. Based on the 24 h LC50 value (70 ppb) obtained from the acute exposure test، a graded series (10، 30، 50 μg Hg/L) of mercury chloride (MC) were administered to Roach fish (Rutilus rutilus) with 48 fish per group. The chemical exposure experiments lasted for 48، 96 and 144 hours. These designed exposure levels were sublethal، and could induce obvious alteration of tissues abnormalities and disease at the same time.