Abstract: An experiment of Zn exposure of Procambarus clarkii was conducted to investigate bioaccumulation of the element in various organs (hemolymph, gill, hepatopancreas, digestive tract, gonad, antennal gland and muscle) of the crayfish as affected by Zn²⁺ concentration (0.40, 4.04 and 40.37 mg•L^-1) in the solution and duration of the exposure (2h, 8h, 1d, 3d, 7d, 14d and 21d). Six crayfishes were taken out randomly from each concentration group each time for analysis of w (Zn²⁺) . Results show that w in gills, hepatopancreas and muscle displayed a rising trend along with the on-going exposure. Their gills and hepatopancreas accumulated more zinc than other tissues, with bioaccumulated concentration factor (BCF) being 407.78, 79.46 and 40.80 and 656.90, 143.58 and 41.39 respectively, in the three concentration groups. However, no significant accumulation was found in such tissues as antennal gland, digestive tract, gonad and hemolymph. In gonad and antennal gland w was increasing steadily at the initial stage of the exposure and then decreasing rapidly and in the end leveled off below that that of the control group. In the digestive tract, w peaked twice in all the concentration groups, in hemolymph it did once only in the two groups low in Zn²⁺ concentration (0.40 and 4.04 mg•L^-1) and three times in the group of 40.37 mg•L^-1. The higher the concentration the crayfish was exposed to, the quicker the first peak of w appeared and the higher it peaked. All the above described findings indicate that crayfish is a species liable to Zinc accumulation from environment, but mainly in gills and hepatopancreas. It is, therefore, advised that for the sake of food safety, do not eat gills and hepatopancreas of Procambarus clarkii caught from the environmental under zinc stress.

Key words: zinc sulphate, Procambarus clarkii, accumulate, heavy metal