*Corresponding author The amount determination of Lc50 heavy metals, Lead and Zinc, at Acipenser stellatus frys, and their histopatological effects on liver and gills tissues

Heavy metals like Zinc and Lead are Known as the main important pollutants of water in rivers wich run and last in Caspian sea.The gool of this study was to determine the Lc50 of Zinc and Leads for Acipencer stellatus frys
and also Analyzing their histopathological effects an liver and gill tissues.This economical fish in Caspian sea is facing toward the densities lower than fatal amount (25%-50%-75%) of lead and zinc . According to the above mentioned, first of all, the Lc50 of these metals were estimated during 96 hours of standard method(O.E.C.D,1989) and static style.All the chemical and physical characters of water Such as,PH,hardness,Dissolved oxygen,… were measured during each experiment.In the next level,the concentrations of Lc50(25%-50% and75%) was determined and in addition in each measuring, fish were in expose of the noted concentration three times.In the following,a witness group was chosen to be taken(the fish)randomly after a week . the work of this group was tube separated all the kidney and gills tissue toward Paraffin style.By applying a microscope with was equipped with a camera,they captured some evidences by the tissues,After this stage the results were expressing ahealthy tissue in both parts (liver-gills).However in the other group with was kept in a special environment fatal concentrations of histopathological side effects was obvious. Symptoms such as cellular necrosis, bleeding Hyperplasia, ect .These side effects were in an increasing line when recorded by 25%. Sample toward the 75% sample .Totally expressing, while comparing these two groups, the liver of special group in our study that has been analyzed, was shown a more healthy stage than the gills of taken fish.