| The main objective of this study is to investigate the biotoxic effect of heavy metals (cadmium (Cd), copper (Cu), zinc (Zn) and chromium (Cr)) in crucian (Carassius auratus of Penze + Cyprinus acutidorsalis . Using Cd, Cu, Zn and Cr as experimental toxicants and crucian as experimental creature, we employed the environmental biotechniques (flame atomic absorption spectrophotometry, the method of improved pyrogallol autoxidation and electron microscopy) to study the acute toxicity and secure concentrations of heavy metals to crucian; the accumulation and distribution of mixed heavy metals to fingling crucian; the activities of superoxide dismutase (SOD) of gill and liver tissues and the hispathological and ultrastructural change of superfine structure of liver and kidney of crucian after cadmium exposure. Through which, we intended to fully and systemically study the toxic influence of heavy metals to fish, and preliminarily discuss the influence of heavy metals pollution to the diversified level of fish such as individual, organ, tissue, cell and molecule. Thus we tried to provide scientific evidence to establish preventative management measures, avoid and relieve the harm of heavy metals pollution to aquicolous ecosystem in time.Six species of edible fishes and six species of edible bivalves were purchased from Shipai market in Guangzhou. The flesh of this biota was tested for their cadmium, lead, chromium, nickel, copper, and zinc concentrations (based on wet weight) using the method of HNQ3-HC104 Digestion and Flame Atomic Absorption Spectrophotometry. The results showed that the abilities of bioaccumulation of bivalves were stronger than those of fish. The concentrations of heavy metals in different tissues in fish were significant different (p<0. 01). Poisonous metals such as Cd, Pb, Cr and Ni were mainly distributed in scale and gill. Forfishes, the content of heavy metals in the edible part were far below Pollution Evaluation Standards for Marine Organism and Healthy Standards for Human Consumption, which was safe to be eaten. Cd content of bivalves had exceeded Healthy Standards for Human Consumption, and the contents of Cu and Zn in oyster had also slightly exceeded Healthy Standards for Human Consumption. Their edible value had been affected, which should be recognized.The acute toxicity of Cu, Zn, Cd and Cr to crucian ( Carassius auratus of Penze Cyprinus acutidorsalis was studied with the static test method. The results showed that Cu to crucian was a drastic toxicant; cadmium was median toxic; zinc and Cr were low toxic. The toxicity sequence of four heavy metals to crucian was Cu>Cd>Zn>Cr. The LC50 of 24h, 48h, 72h and 96h for Cu to crucian were 0.23, 0. 14,0. 11 and 0. 09mg/L. Those for Zn were 11. 17, 8. 68, 6. 86 and 5. 85mg/L. For Cd and Cr there were 390.30, 311.80, 277.70 and 244. 10mg/L, 39.40, 32. 25, 27.20 and 22. 25mg/L. The safe concentrations of these metals were 0. 009mg/L> 0. 59 mg/L, 24. 41 mg/L and 2.23 mg/L respectively. The safe concentration of Cu to crucian was slightly lower than Standard of Fishery Water Quality. The safe concentrations of Zn, Cd and Cr to crucian were far exceeded the standard.The short-term accumulation and distribution in young crucian tissue of mixed secure concentrations of heavy metals Cu, Zn, Cr and Cd pollution was studied. The results showed that associated interaction of the four heavy metals was synergistic effect of accumulated toxic. The accumulation of Cd and Cr was evident in gills and livers (p <0. 01) and wasn' t evident in muscles. Zinc accumulation was evident in livers at 12h and 24h after exposure (P |
PDF Full Text Request