Study of bioaccumulation and sublethal effects of Zinc Chloride on the liver structure of gray mullet (Mugil cephalus)

Heavy metals such as Zinc (Zn) are pollutants in aquatic ecosystems that create many difficulties for the aquatic organisms and eventually humans. In the present research, sublethal effects of Zinc Chloride (Zncl2) were studied on bioaccumulation and liver structure of gray mullet (Mugil cephalus) during experimental condition. Fish were captured for experiment from Chabahar Bay with an average weight of 7.24±0.5 g and total length of 6.15±0.2 cm. According to the lethal concentration and LC50 for this species, a control group and two treatments with different concentrations of 1.73 and 3.46 mg/L, each group with 3 replicates, were used for induction sublethal concentration. Fish were exposed to sublethal concentrations for 1, 7, 14 and 21 days. At the end of each stage, liver tissue of fish were removed for histopathology examination and also on metal bioaccumulation. Result of liver tissue histopathology showed lesions such as bleeding complication, hepatocytes vacuolization and sinusoid dilation, nuclear hypertrophy, leukocyte infiltration, melanomacrophages aggregates and necrosis. Extent and severity of the lesion were increased with increasing Zinc Chloride concentration and exposure time. So that the highest lesions were for second treatment and 21 days. Also, the accumulation in the liver increased significantly with increase of the sublethal concentration (p