Abstract:We evaluated the chronic toxicity of zinc sulphate in the crayfish 2+ for 21 days. Each day, we randomly selected five crayfish in each group and collected samples of the hepatopancreas, gill, and muscle tissue from males and females and ovarian tissue from each female. The tissues were placed in Bouin’s fixative for 24 h,rick red particles in the hepatopancreasantennal gland in animals exposed to . The number of these particles was positivelyand exposure time. There was no obvious . We observed bleeding and necrosis in hepatopancreas, antennal gland, and gills in the group exposed to 4.04 mg/L after 7 d. The proportion of necrotic cells increased as the concentration of Zn2+ and time of exposure increased. We observed spermatocyte necrosis after 14 d in exposure to 40.37 mg/L Zn2+. After 21 d, we observed bleeding of the spermary and ovary and necrosis of the ootid and spermatocyte cells. A large number of hepatocytes exhibited necrosis and had dropped from the hepatic ducts. The connective tissue exhibited hyperplasia, with large numbers of cells blocking the hepatic ducts, resulting in in the hapatopancreas of the group exposed to pathological changes in the hepatopancreas, antennal gland, gills, and gonad tissue of . Given that zinc sulphate interferes with the metabolic, respiratory, and reproductive systems, chronic exposure is likely to threaten the survival of