Toxicity of three heavy metals to Macrobrachium rosenbergii. In：R. Hirano and I. Hanyu (eds.)

Abstract

The acute toxicities of Cu, Cd and Zn to various larval stages of the giant freshwater prawn, Macrobrachium Tosenberaii, and the effects of three heavy metals on the survival and growth of juvenile prawn (0.78 + 0.05 g), and their accumulation and elimination in the young prawn (4.76 + 0.43 g) were studied. The results showed that the tolerance of various larval stages of prawns to Cu, Cd and Zn reduced as development advanced and that the toxicities of three heavy metals to the prawn differed at each stage. The growth and survival of the tested group prawn (8 ppb for Cu ; 1, 2, 4, 8 ppb for Cd and 200, 400 ppb for Zn) were significantly less than those in the control group (p<0.05). Among the tissues tested (shelled cephalothorax, muscle and shell), the shelled cephalothorax obtained the highest accumulation. The accumulation rates varied with the kind and the concentration of heavy metals. These generally peaked after 8-16 days of exposure, and either remained stable or declined thereafter. Higher concentrations also resulted in higher levels of accumulation. When the prawn were transferred to clean freshwater after 32 days of exposure, the accumulated heavy metal markedly decreased over a 20-day period.